ssc-313 (sl-7-28) sl-7 research program summary, conclusions and
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SSC-313(SL-7-28)
SL-7 RESEARCH PROGRAMSUMMARY, CONCLUSIONSAND RECOMMENDATIONS
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SHIP STRUCTURE COMMITTEE
1981
SHIP STRUCTUSECOMMITTEE
l%e SHIPSTRUCTUSECOMMITTEE is constitutedto prosecutea researchpro&r= tO iwrove the hull structures of ships d .Ch= =r~ne structuresby an =te.~i.n .f ~owledse P=catnin’st. design,=ceri*ls and methodsofconstruction.
P.AdmClydeT. Lusk,Jr. (Chairman) Mr. J. GrossChief,Officeof MerchantMarine DeptmyAssistantAdministratorfor
Safety CommercialDevelopmentU. S. CoastGuardHeadquarters MaritimeAd!niniscracion
Mr. P. M. Palermo Mr. J. B. GregoryExecutiveDirector Chief,Research& DevelopmentStaffShipDesign& Integration of Planning6 Assessment
Directorate U.s. GeologicalS“l-?eyNavalSea SyscensCommand
Nr. W. N. klannan Mr. Tbom.4sW. AllenVice President ChiefEngineeringOfficerAmericanB.rea”of Shipping MilitarySealiftcommand’
LCdr D. B. Anderson,u.S. CoastGuard (Secretary)
sHIPsRucTuss SOECOKMITTEE
The SHIPSTRUCTUBISUECOFNfITTEEacts for the ShipStrucc”reCommitteeon technicalmattersby providingtechnicalco.ardir.ati.mfor thedeterminationof goalsand objectivenof the program,and by evaluatinga“dinterurecins rhe resultsin term of str”ct”raldesizn.constructionand. .operation.
U. S COASTGUARD
Capt.R. L. srowoCdr.J. C. CardH.. K. E. William’..Cdr.J. A. Sa”ialLCdrD B ,lr,derso”, Secy.
NAVALSEA SYSTEMSCO-
Mr. R. ChiuMr. J. B. O’Brien?+. ‘J.C. SandbersLcdr D. W. WhiddonMr. T. Nomura(C.antraccsAdmi”.)
144R1T1M3ADM1N1SIRATION
Mr. N. 0. HammerDr. W. M. wacleanMr. F. SeiboldHr. M. Towsa
NATIONALA~W OF SCIENCESSHIPRSS~RCH COMMITTEE
M.. A. DudleyHsff - LiaisonMr. R. W. Rtmke - Liaison
SOCIETYOF NAVALARCHITECTSbMARINEENGINESRS
Mr. A. B. Stavwy - Liaison
WSLDINCRESEARCH COUNCIL
m. K. H. Koopman - Liaison
MILTARYSl?.dLIFCC0FCi4ND
Mr. ALbertAttermeyer14r.T. W. ChapmanMr. A. B. Stavo.rjMr. D. Stein
AfCZRICANBUREAUOF SHIPPING
Dr. D. LiuMr. 1. L. $terz
U. S. GEOLOGICALSURVSY
Mr. R. Giar.geralliFir.CharlesSmith
1NTEsNATIoNALSHIP STRUCTURESCONGRESS
Mr. S. G. SCianse”- Liaso”
MCSRICANIRON & STEELINSTITUTE
Mr. R. H. Scerue- Liaso”
STATEUWIV. 0P NSW YOSK M.4R1T1~COLLEGE
Dr. W. R. Porter- Liaison
U S. COASTGLAF.DACADE?Cf
LCdr R. G. Vorthman- Liaison
U. S NAVALAWE-N
Dr. R. Battacimryya- Liaison
U, S. MERCHANTMARINEACADEMT
Dr. chim-BeaKin - Liaison
MemberAgencies:
lhiwd StatesCoastGuard
Military Bdlft CommendSlsrltinwAdministration
@fsodSatasGeological.%rv.?yAmsriean BureauofSipping
*
S&ctufcCemmittce
AddressCorrespondenceto:
Secretary,ShipStructureCommitteeU.S.CoastGuardHeadquarters,(G-M/TP13)Washington,D.C.20593
An InteragencyAdvisor CommitteexDedicatedto Improvingthe tructureofShips SR-1279
1981
This report is one of a group of Ship Structure ConnnitteeReports which describe the SL-7 Instrumentation Program. Thisprogram, a jointly funded undertaking of Sea-Land Service, Inc., thePmerican Bureau of Shipping and the Ship Structure Consnittee, representsan excellent example of cooperation between private industry, regulatoryauthority and government. The goal of the program is to advance under-standing of the performance of ships’ hul1 structures and the effective-ness of the analytical“andexperimental methods used in their design.Whi1e the experiments and analyses of the program are keyed to the SL-7Containership-and a considerable body of the data developed relatesspecificallY to that ship, the conclusions of the program wi11 be coM-pletely general, and thus applicable to any surface ship structure.
The program includes measurement of hul1 stresses, accelerationsand environmental and operating data on the S.S. Sea-Land McLean,development and installation of a microwave radar wavemeter for meas-uring the seaway encountered by the vessel, a wave tank model studyand a theoretical hydrodynamic analysis which relate to the wave in-duced loads, a structural model study and a finite element structuralanalysis which relate to the structural reponse, and installation oflong-term stress recorders on each of the eight vessels of the class.In addition, work is underway to develop the initial correlations ofthe results of the several program elements.
throughan SL-7to date
Results of each of the program elements are being made avai1ablethe National Technical Information Service, each identified bynumber and an AD- number. A list of all SL-7 reports availableis included in the back of this report.
This report documents a review of the .SL-7research programwith a suimtaryof each aspect and outside ancil1ary projects; presentsa set of conclusions. and makes reconsnendationsfor further analysisof some data.
RearChairman, Ship Structure Consnittee
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SSC-313 (SL-7-28)
4.11,1..nd Sub!,!l. 5. Rwo,,Det.
sL-7 Research Program Suumary, Conclusions and August 1981
Recommendations 6.P..t.rm. i.* Or*.., z.*,.. C4.
8. P.v+.mw.e Of*.n; *.Ii.6 R.prl Pd..f, A.lh.r, ,)
Karl A. Stambaugh and William A. WoodSR-1279
9.P.r{.rm.g O,OEI, ,.,,.. N-, o?d Addr., , 10. w.,b u.,, No. (TRA!S)
Giannotti 6 Associates, Inc.
703 Giddings Avenue, Suite u-3 11.b.,,,.,o.G,.nt N..
Annapolis, Nsryland 21401 DTCG-23-80-C-20025
13.T,,..1R.,.,, .IId P.,;., C...d.d
12. &ns.ri.$ A...cv Nm.,. md Add,... Technical Report
U.S. Coast GuardOffice of Merchant Marine Safety
8/14/80 - 8/10/81
Washington, D.C. 20593 }4.SCW,,e,,,m4..... bd.
G-M15.SwPel,m..,s,,No*.$
Contract monitored by: Ship Research CommitteeNational Academy of SciencesWashington, D.C.
16.Ab,,mcl Horn Its tlrst inception, the SL- I containership program represented a mile-
stone in maritime tiistory. The SL-7S advanced the state of the art in such areas as
iesign, classification, construction and ship operations. It was indeed fortunate
hen the opportunity presented itself for the Ship Structure Committee to participate
in a research program for the full-scale measurement of hull girder stresses on thesevessels. Like the sL-7 vessels themselves, the full-scale measurement program has be-come a milestone itself.
The report that follows, “SL-7 Research Program: Summary, Conclusions and Recommenda-tions,” reflects mainly upon the technical content of the program. This report cOn-tains an evaluation of the SL-7 research program according to four main elements,namely, Full-scale Instrumentation, Model Testing Techniques, Analytical Techniquesand HU1l Girder Load Criteria Analysis. Conclusions are derived from the evaluationwith emphasis on how the program results may benefit future programs of similar nature
The report contains appendices summarizing the relevant sL-7 research program documentation and describing the data recorded on the S.S. SEA-LAND McL~ that ShOuld aid
future data users.
At this time,it appears obvious that the SL-7 program has been a tremendous success.The massive amounts of full-scale hull response data that have been recorded will un-doubtedly be a most valuable source of data for researchers, designers and studentsfor ,many years to come. The program has greatly increased our knowledge and understandifigof the sea and the ships that sail on it. As a program involving many disciplinewithin the marine industry, it has fostered a spirit.of cooperation and cO~unicationwithin the industry. These long-term benefits represent the real success of the sL-7-—17.K.” W..d, I 11, Oiswi huttom St.1.me”f research program.
Ship ResearchShip StructuresStructural AnalysisShip Response and Instrumentation
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CONTENTS
Eszas
1.0 INTRODUCTION ................................................. 1
2.0 BACKGROUND ................................................... 1
2.1 INFLUENCE OF PRIOR WORK LEADING TO THE SL-7 RESEARCHPROGRAM ................................................. 2
2.2 DESIGN OF THE SL-7 CONTAINERSHIP ........................ 2
3.0 REVIEW AND SUMMARY OF THE SL-7 RESEARCH PROGRAM .............. 3
4.0 EVALUATION OF THE SL-7 RESEARCH PROGRAM ...................... 11
4.1 EVALUATION OF INDIVIDUAL SL-7 PROJECTS .................. 11
4.2 SUMMARY OF THE SL-7 RESEARCH PROGFUM EVALUATION ......... 11
4.2.1 Full-Scale Instrumentation ....................... 114.2.2 Model Testing Techniques ......................... 554.2.3 Analytical Prediction Techniques ................. 554.2.4 Load Criteria, Analysis and Development .......... 56
4.3 OVERALL EVALUATION OF THE SL-7 RESKARCH PROGRAM ......... 57
5.0 RECOMMENDATIONS .............................................. 59
6.0 ,EPILIXUE, WE sL-7 CONTAINERSHIP ............................. 61
7.0 ACKNOWLEDGEMENTS 61
8.0 REFERENCES 62
APPENDIX A - SUMMARIES OF REFERENCES 1 - 34 ................. A- 1
APPENDIX B - SL-7 RESEARCH PROGRAM DATA BASE DESCRIPTION .... B- 1
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LIST OF FIGURES
Figure 2-1
Figure 2-2
Figure 3 1
Figure 4-1
Figure 4-2
Figure 4-3
Figure 4-4
Figure 4-5
Figure 4-6
Figure 4-7
Figure 4-8
Figure 4-9
Figure 4-10
Figure 4-11
Figure 4-12
Figure 4-13
Figure 4-14
Figure 4-15
Figure 4-16
Figure 4-17
Figure 4-18
Midship Section of the sL-7 Clsss Containership ..............
SL-7 Body Plan, Stareand Stern Outlines and Curve ofSectional Aress ..............................................
Representation of an Open-Decked Ship ........................
SL-7 Data Comparison .........................................
Hatch Deflection Measurements from the Calibration Experi-ment Performed on the SL-7 SEA-LAND McLEAN ...................
Comparison of 4 HMS Estimates from the OWHS Radar with Cor-rected 4 RMS Estimates frnm the Tucker Meter: All Intervals ..
Comparisons of 4,RMS Estimates from the OWHS Radar with Cor-rected 4 SMS Estimates from the Tucker Meter: IntervalsPlotted are Restricted to Those for Which tbe Radar Spec-trum Area above the Low-Frequency Integration Cutoff isGreater than 80,%of Total ....................................
Histograms of Scratch-Gauge Data Measured on the SL-7
Resource .....................................................
Miscellaneous Details of Scratch Records .....................
Illustration of Scratch+iark Equivalent to Complex ‘TimeHistory of Stress ............................................
Comparison of sL-7 Stresses at Frame 178 During PositiveTorsion ......................................................
Representative Loading Applied to the Steel Structural Model .
Hatch Distortion vs. Stresses in Transverse Box at Fr. 178,Port Side-Section B due to Torsional and Lateral Moments forthe SL-7 Containership .......................................
Stress Distribution due to Wave-Induced Vertical BendingFr. 142-146 Second Loading Case ..............................
Stress Distribution due to Lateral Bending and Torsional
Moments Fr. 142-146 Second Loading Case ......................
Midship Vertical Wave Bending Moments and Wave Phase Lag,180° Heading .................................................
Midship Vertical Wave Bending Moments and Wave Phase Lag,0“ Heading ...................................................
Midship Torsional Wave Bending Moments and Wave Phase Lag,30” Heading ..................................................
Midship Torsional Wave Bending Moments and Wave Phase Lag,2400 Heading .................................................
Midship Vertical Wave Bending Moments and Phase Lag, 180”Heading ......................................................
Midship Vertical Wave Bending Moments and Phase Lag, 0°Heading ......................................................
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14
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20
20
23
24
25
29
30
32
33
33
35
36
37
38
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LIST OF FIGURES (cent’d)
Figure 4-19
Figure 4-20
Figure 4-21
Figure 4-22
Figure 4-23
Figure 4-24
Figure 4-25
Figure 4-26
Midship Vertical Wave Bending Moments and Phase Lag,
300 Heading ...............................................
Midship Torsional Wave Bending Moments and Phase Lag,240° Heading ..............................................
Comparisons of Structural Model Tests and Finite-ElementCalculations for the SL-7 Containership, Loading Case 1 ...
Comparisons of Structural Model Tests and Finite-ElementCalculations for the SL-7 Containership, Loading Case 2 ...
Comparisons of the Wave Time History Measured on theSRA-LAWD MCLEAW and the Regular Wave Representations(Condition 15 - Voyage 32w - Tape 145 - Index 18 -Interva15-Run 405) .....................................
Comparisons of the Wave Time History Measured on theSEA-LAWD McLEAN and the Regular Wave Representations(Condition 16 - Voyage 32w - Tape 145 - Index 29 -Interva150 -Run 45(l) ....................................
Comparison of the Calculated and Measured MidshipVertical Bending Stresses (Sensor LVB) , WaveCondition15 ..............................................
Comparison of the Calculated and Measured MidshipVertical Bending Stresses (Sensor LVB), WaveConditlon16 ..............................................
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LIST OF TABLEs
TABLE 2-1 CHARACTERISTICS OF s.S. SEA-LAND McLSAN ............... 6
TABLE 3-1 SUlfMARYOF SL-7 RESEARCH PROJECT USING THE SL-7DATA OR AS REPRESENTATIVE HULL TYPE ................... 10
TABLE 4-1 EVALUATION OF THE sL-7 RESEARCH PROGRAM ............... ~j
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1.0 INTRODUCTION
The SL-7 is an eight-ship class of high-speed containerships conceivedowned and operated by Sea-Land Services, Inc. (Sea-Land) in both NorthAtlantic and Pacific trade routes. A research program involving theseshipa was initiated by Sea-Land, the American Bureau of Shipping (ASS)and the Ship Strncture Committee (SSC), with additional projects fundedby the United States Coast Guard and the United States Navy. The prO-gram represents an excellent example of cooperation among private in-dustry, classification societies and government. The goal of the pro-gram was to advance the understanding of ship structural performance andthe effectiveness of analytical and experimental methods used in design.A long-range goal of the program was to obtain information for reachingthe SSC’a goal for the development of rationally-baaed system load cri-terion for the design and analysis of ship hull structures. While thefull-scale meaauraments, model experiments, and analyses performed aspart of this program were keyed to the SL-7 class containerships, manyof the conclusions of the program can be generalized and applied to othersurface ships. This report includes a summary of the overall program,outlines some of the details of the program planning, describes the cor-relation, comparison and validation efforta, and finally, addresses re-commendations for further analysis of the SL-7 program data base.
This report is organized into four basic sections. The first sectionpresents the background leading up to the initiation of the SL-7 researchprogram. The second part presents a review and summary of the SL-7 re-search program and describes the program elements and general goals ofSSC that form the common thread for the program. The second section isintended to provide the reader with some insight as to the relationshipsbetween the various program elements. The third part of the report con-tains an evaluation of the research program documented in References 1-34,relative to the program goals and objectives, and an overall summary ofthe conclusions is presented baaed on the evaluation of the research pro-gram, The fourth and final part of the report presents the recommenda-tions which may be derived from the SL-7 research program.
Two Appendices are included which provide background information pertinentto the evaluation, conclusions and recommendations. Appendix A containsindividual summaries of References 1 through 34, and Appendix B containsa description of the full-scale data base of ship response informationrecorded on the S.S. SEA-LAND McLRAN.
2.0 BACKGROUND
The SL-7 research program has deep roots in the research history of theSsc. This program was preceded by other programs which included exten-sive model teats, computer analyses and full-scale data collection andanalysis. In fact, moat of the full-scale vessel instrumentation tech-nology in use today was developed under the sponsorship of the SSC. Inplanning for the SL-7 Research Program Summary, Conclusions and Recommen-dations, it was necessary to review the reports of the preceding relatedprograma in order to provide a basis from which the SL-7 research program
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2.1
2.2
has evolved. Nany of these prior programs have had a profound impact andinfluence in the formulation of methods for full-scale ship data acquisi-tion, in stimulating related research in the private sector, and in ad-vancing the state of the art for ship design.
INFLUENCE OF PRIOR WORR LEADING TO THE sL-7 RESEARCH PRoGFQIM
The background research that preceded the SL-7 research program is dis-cussed in detail by Siekierka, et al in SSC-257 (5) . It is from thisbackground that the sL-7 research program haa evolved. The follnwingis aSL-7
1.
2.
3.
.4.
5.
synopsis of the influence of these studies on the elements of theprogram:
Previous full-scale instrumentat ion programs have provided valu-able ship hull load and response data that facilitated the develop-ment and validation of design methods and techniques. Hnwever, aquantitative description of the wave environment was lacking.
The analytical techniques for predicting ship bending moments dueto wavea have not been validated directly using full-scale databecause of the absence of accurate wave information in previousfull-scale programs. The wave data are essential to further developload-prediction techniques and to achieve a greater confidence inthe results of the predictions.
The full-scale stress data that have been collected are helpful inexamining load design criteria for ships similar to those for whichstress data are available but cannot provide direct guidance indesigning different types of ships.
A technique has been developed for extrapolating full-scale shipwave-induced bending moment data and is based on environmental dataencountered by the ship in question. This technique may alao beused to synthesize bending moment data by using model test resultsor computational analysis and provides the designer with a valuabletool in predicting wave-induced bending momenta.
The ship structural load criteria presented in SSC-240 (35) neededfurther validation and development for use with different ship typesand varying types of load conditions.
DESIGN OF THE SL-7 CONTAINERSHIP
The concept of a high-speed container ship waa conceived by Sea-Land in thelate 1960s. At the time, fossil fuel was still relatively inexpensive,and it appeared that the high-speed containerships were the way of thefuture for cargo tranaport. The design of the SL-7 waa begun in early 1969by Sea-Land, J.J. Henry, and The Netherlands Ship Model Baain (NSMB).
The structural design considerations for the SL-7 class of containershipawere presented by Boylaton (36) and represented the state of the art atthe time in applying design tools and methods. During the initial
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investigations, the application of modern design methods was still in itsinfapcy and consequently the analyses commenced at a simple level, buildingup to more sophistication as the work progressed.
The design bending moments were determined statically on a wsve equal tothe ship length and of a height equal to 2.2 LO.4 = 30 ft. It waa deter-
mined that the hogging momenta were larger than the sagging moments by afactor of about 4 (36). A dynamic analyais was conducted based on themethods presented by Grim and Schenzle (37). The torsional rigidity Ofthe containership waa also considered in the design stages, where the tor-sional moment was determined using the procedure outlined by deWild (38).
Concurrently with the determination of the wave loading, a course meshfinite-element model of the ship was developed. This was one of the earlyattempts to model a whole ship. The structural analysis showed that deckstructure in way of the engine apace and transverse bulkheads between eachhold limited the torsional-induced warping and deflection of the hull gir-der, thus minimizing the torsional deflections at the hatch corners nearthe ship’s quarter points. The resulting midship section as constructedis shown in Figure 2-1. The body plan is presented in Figure 2-2. Anadditional finite-element analysia was conducted with a much finer mesh aspart of an extensive vibration analysis.
A series of model studies was conducted at the NSMB (36) with emphaais onhull form development and resistance. Seakeeping testa were also conduc-ted and measurements were obtained for ship motions, accelerations andrelative motions at the bow and stern in irregular seas corresponding toa wind force Beaufort 8 in the North Atlantic (significant wave height16 ft. and average period 8.5 sec.) approaching from ahead, the bowquarter, abeam, and the stern quarter. The relative motion data indi-cate that for this sea state no water would be shipped over the foredeck.However, emergence waa not experienced and it was concluded that slammingwould be minimal in Beaufort 8 seaa.
There were 8 vessels of the SL-7 claas constructed at three differentEuropean shipyards, which included Rotterdam Dockyard, A.G. Weser, andRheinstahl Nordseewerke. The vessels were:
S.S. SEA-LAND McLEAN S.S. SEA-LAND FINANCEs.S. SEA-LAND GALLOWAY S.S. SEA-LAND MARRET
S.S. SEA-LAND TRADE S.S. SEA-LAND RESOURCEs.S. SEA-LAND ERCHANGE S:S. SEA-LAND COMMERCE
The principal characteristics of the lead ship of the SL-7 class, the
s.s. SEA-LAND McLEAN (McUAN), am Shown in Table 7=1.
3.0 REVIEW AND SUMMARY OF THE SL-7 RESEARCH PROGRAM
3
A three-phase SL-7 research program was proposed by Sea-Land and ABSbefore the SSC became involved. Sea-Land was interested in instrumentingthe firat ship of the class, the McLEAN, in order tO validate design de-cisions and procedures, while ABS was interested in conducting finite-
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TABLE2-1
CFIAFU.CTERISTICSOF S.S. SS.4-LANDMCLEAN
Name :
Builder:
class:
Length,overall
Lengrh,betweenperpendiculars
Beam,molded
Depthco maindeck,aft ~
Depthto main deck,for.mrd%
Camberfrom~
Draft,design
Draft,scantling
Deadweight- low ton,
Displacement(34,0,,draft) - longtons
Machinery
ShaftHorsepower-maximumcontinuous,both shafts
Propellerm
SPeed,maximum,knots
Centerof gravity- fullload
Sectionmodulus,FR 186,top:
Sectionmodulus,FR 1S6,bottom:
Neutralaxis,~ 186
Fueloil CaPaciEy(98%full)
SaltwaterBallastCapacity
S!2A-LAND MCLEAN
RotterdamDry Dock (Hull330)
SL-7Contair,er,hip
946q lW
880!6,’
105,6,8
69r 9,,
65, 3,,
~, ~,!
30, 0,,
33!0,,
27,315
50,315
Two separatecross-cou,pcmndstem turbinesdrivingtwoProPellershafts(BunkerC oil)
120,000
135
33
399.32!forwardof aftper-pendicular42.65’abovebase line
1,745x 106 in3
2,166x 106 in3
342.5in abovebase line
5384LT
9656LT
ContainerCapacity
81 x8.5, x 35, 8’ x 8.31x 40, ~
Belowdeck 554 160 694Abovedeck 342 60 402
TOTAL 896 200 1,096
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element analyses and structural model tests in order to exercise andvalidate their relatively new finite-element computer program, DAISY.SSC ev~ntually became involved in the project and supplied additionalfunds and technical guidance through a Project Advisory Committee of theNational Academy of Sciences/National Research Council.
Several design-related problems prompted the initiation of the sL-7 re-search program. Each participant, Sea-Land (designing, building andoperating) , ABS (classification) , and SSC (research) , had specific in-terest goals to achieve through participation in the program.
The specific design features of intereat to Sea-Land were primarily inareas of stress concentration at the hatch corners where the ship tran~-forms from a flexible open box to a rigid closed box structure and wherethe transverse box girders interact with the longitudinal box girders.These locations are represented in Figure 3-1. They were also ofspecial interest since the diagonal displacements of hatch openings sub-sequently caused large atresses at the girder intersections and problemswith the hatch cover seals.
One of the primary goals relative to SSC’s objectives for the full-scaleportion of the SL-7 research program was stated in Siekierka in SSC-257,
Reference 5, “The results of the wave-induced stress measurements (onthe McLEAN) will be compared with model and computer analytical data.The ultimate aim is to secure sufficient confidence in the calculationprocedure, so that model testing and full-scale data collection may beeliminated, ” Further application of full-scale data discussed in thefollowing aectiona will consider Siekierka’s statement as one of theprimary objectives of the full-scale instrumentation installed on theSL-7 class of ships.
As stated by Chazal in SSC-252 (39), the overall goal of tbe SSC for theSL-7 research program was to “either develop or provide supporting evi-dence for rational design methods for ships.” Fundamental to anyrational design method ia the ability to characterize the actual struc-ture using predictive techniques such as mathematical analysis or modeltesting. With either method, correlation factors must be applied whichrelate the predicted results to the actual full-scale structure. Deter-mining these correlation factors and refining the predictive techniquesare implicit objectives of research into ship structural design methods.Within this framework and the historical background presented, the SL-7research program was developed with the followirig four distinct elements:
1. A full-scale instrumentation project consisting of measurement ofhull stresses, rigid-body accelerations and environmental data,and long-term extreme strain recorders.
2. Uae of model-testing techniques for the prediction and validationof ship dynamic and static loads and responses.
3. Development and validation of analytical tools and techniques forship mot ion, load and response characteristics, including finite-element computer programa.
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Figure 3-I Representation
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of an Open-Decked Ship
Strain gaugelocat ion
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4. Development and analysis of lifetime hull girder load criteria forship structural design based on statistical evaluation of full-scale data.
In subsequent sections of this report, each of these elements, theirinterrelationships and impact on design methods, will be summarized andevaluated with respect to the program’s objectives and goals.
The SL-7 research program as initially conceived contained specific in-dividual projects to implement the broad program elements.
1. A full-scale instrumentation program was proposed to obtain full-
scale measurement of seaway loads and response. This included the
design and installation of an instrumentation system, the calibra-tion and operation of this system, and reduction and analysis ofselected amounts of data.
2. A series of hydrodynamic model tests were proposed to investigate
wave-induced vertical, horizontal and torsional bending in the hullgirder.
3. A model ‘test was proposed to measure stresses and deflections of asmall-scale structural model under separate and combined torsionand bending.
4. An analytical analysis was to be conducted which included the useof a finite-element program, DAISY, to analyze the structural res-ponse of the SL-7 containership.
5. A theoretical hydrodynamic analysis was to be performed applyingthe SCORES computer program for predicting the loads and responseof the SL-7 containership in regular waves.
It should be emphasized that prior to completion of the full-scale instru-mentation data reduction and analysis, the other program elements wereinitiated. The relationships between projects listed above are describedin SSC-257 (5), which includes a description of the planning effort in-volved in the validation and verification of load, motion and reaponaepredictions. Not all of the recommendations for research presented inSSC-257 (5) were funded, and several were integrated into one project.Aa the program evolved, it developed into a more extensive program whichincluded further analysis of data obtained from the initial program anddevelopment of additional related projects. These follow-on projectscontinued the validation and development efforts and full-scale datareduction that had begun in the initial part of the sL-7 research program.
Moat of the results of the SL-7 related research projects have appeared
aa SSC reports. Summariea of all SL-7 related project reports and tech-nical papera are presented in Appendix A. Some SL-7 related projectahave received separate Coast Guard, Navy, or ABS sponsorship. The pro-jects which will be evaluated in this report are listed in Table 3-1.A description of the McLEAN data base is presented in Appendix B. This
9I
L——.
TABLE 3-1
L-7 PROCR4MELEM2NTS
Full scaleInstr”mentat 10”
,odel TestirIg -‘echniques
,n.ly tical ‘Ce.hniques
“11 Girder Load!Yiter ia Analysis
SLPMASYOF sL-7RESSARCEPF.43JECTUSIWSTM!&SL-7MIA OR ASSEFSSSENTATIVENULL TTFfi
PROJECT ORIGIN ASSOCIATED(locationof data) REFERENCES
Nullresponseneas.rement.. the Teledyne Engineering 1 7 8SL-7 S2.4-LAND MCLEAN Services ‘9,’1O’
Shipboard wave neasurernent Teledyne Engineering 10
Wscems 0. the SL-7 SEA-LAND servicesMcLEAN
Naval Research Lab 13
Stevens Institute 14-23*of Technology
Scratch gauge dam on the sL-7 Teledyne Engineeringcla.sa mntaine.s hips services 25
(incl.dins the McLEAN)Gfannotti & Assoc. , 3 L*1*C
1/lhOth Scale model tests
I
Stevens Instituteof che sL-7 of Technology 12 I
Steel structural model t,s CS of U“ivers icy ofthe SL-7 California, Berkeley 11
PVC rigid vinyl structural model David Taylor Naval[e, CS of the SL-7 Ship Research &
Development Center 6
Open water model C.SCS of che University ofSL-7 Celiforr,ia , Berkeley 26,27
Hull Pressure model cescs of the University of ●*
SL-7 Michigan
SCORES computer simulations of Ocea”ics , l°C 4, 12the SL-7
DAISY Finite Element Analysis
I
American Bureau of
II
3, 24, 30of the sL-7 Shipping
1 1Time domain computer sim.lat ion University of 26,28,29of capsizing for tbe sL-7 California, Berkeley
Examinationof SW”%,, stress Stevens Institute 33*data (includes the SL-7 as a of Technology andship type) Kosenhlatt & Son,
lnc.
Evaluation of full scale wave Hs-1 Panel, SNAME 34*loads (includes the SL-7 as aship type)
Fat i~ue load ,Peccra development Giannotti & Assoc. , 32*for ship hulls 1...
* Based . . full scale data obtained from Teledyne Engineering Services
** N. dc, cum.. t ha. b... published C. date.
10
4.0
4.1
4.2
4.2.1
description presents a summary of the data acquisition, data reductionmethods, and data formats.
EVALUATION OF THE SL-7 RESEARCH PROGRAM
his section provides an overall evaluation of the SL-7 research program.Section 4.1 discusses the validity snd usefulness of the results derivedfrom each project in the four main program elements described in Table
3-1. Section 4.2 summarize the evaluation, conclusions and contributionsmade by esch project in the four main program elements. Section 4.3 pre-sents an overall evaluation of the SL-7 research program.
EVALUATION OF INDIVIDUAL SL-7 PROJECTS
Evaluations of each of the projects listed in Table 3-1 have been cate-gorized according to the four main elements of the SL-7 research programand are summarized in Table 4-1. The contributions of esch project inachieving the SL-7 program goals are summarized with respect to develop-ment of specific structural design methods, motion and load measurementand prediction techniques, and rationai hull girder load criteria. Inmany caaes, the evaluations of individual researchers are presented withadditional cnmments on overall observations, assumptions, limitationsand applications of the projects considered. Special attention is givento the lessons learned from the SL-7 research projects that may be of
benefit to future data users and those considering other programs of asimilar nature.
SUMMARY OF THE SL-7 RESEARCH PROGRAN EVALUATION
This section presents a summary of the sL-7 research program evaluationwhich includes the primary observations obtained frnm the evaluations ofeach individual report (References 1-34) presented in Section 4.1. Asper the individual evaluations, the summary is organized according to thefour elements of the SL-7 research program.
Full-Scale Instrumental ion
Although the McLEAN data base has several limitations, it still representsa major source of full-scale data for use by the marine community in gen-eral. The major limitations of the McLEAN data base have been indicatedin the evaluation section and include the lack of an initial mean stressdatum prior to departure for each voyage (-thegauges were zeroed prior todeparture and no record of the initial mean stress was kept), the inade-quacy of motion measurement devices (roll and pitch pendulums) , and theunreliability of measured wave data. The latter limitation of the data
base severely limits further applications relative to verification ofanalytical prediction techniques. The research plan outlined by
Siekierka in Reference 5 was heavily oriented to using the McLEAN database for validation purposes. The wave-measurement limitation has pre-cluded the achievement of this goal. It is also interesting to notethat the research ulan did not include hull girder load criteria analy-sis andheavily
developmen~ even thoughoriented toward gaining
the data collection techniques werea substantial statistical sample.
11I
L.
=,.!
EVALUATIONOFTHESL-7 RESEARCM PROGRAM
.,----- “,, , . . . . . ,Uc.., ,.”-. ..”u.,-,,.,,. c.”. ---- ,,.. .”..-... .“”
ROport1111. Cant ,Ibu,,.n of ,h. Study 1“ AchW,ns tln SL -7 tinmch P,o#.eI GLUI.Ssc No.
R.,. no.StrUCtUr.1 Llms1m”WI h.d, SP.C, 1,. ,. th.
Pub. n.,. U...unmmmm ,md Pr*dl.1 Ion 01 Sillp R.tl.”.l Hull Qti,da, L.ti Crlt. r,,SL - 7 ,nd C.”,., ”.,, II,P. ,“ G.nw., L..d, “.,,.m .nd S,,... A..ty.ts ●nd cmv,l.pm..”l In.lud,rq
S,.t I.tk.l EvmluMlmI 01 D.t .
De.,,” . . . ,.s,., ,.,,.. ., . . “.., ., the ,nstr”.e”t ,O==,,.”s . NO load. per ., ..,, .e..u.ed . . the$!,’, ..s,””s, ,n.tm.E.,.,,m,
. ,),. .4.,. ,(>, ,,., ,.,” tech., qu, s WC,“em intended ,. ,...,.3. ,,s,,.
system ,b.ard tt,e s-, c,...SL-7, .“1, .,s,..s.s. $leasum.m, h,..,,, .,,..,4 ,...,, “b,., ”’.,
I. foma,,.. ,. Sea.k.d directly. of the ..,. ..,,,. -., . . ..0”,., ”,,s,,, ,.s. sm.LAND
a .Cai, s,, c., ,.,. sample . . . W,,.Cmmp,ed ..,”* a Tucker ..,, m,..
*LEA” . 5s.-!..”, obtained d,.. ,“ “b“., . . ..8s!.., ,, .-,., ,,,, .,,,
and . r.dar wave =,,.. II,.$X.2,8
“.,,.3 .,,.” 0, ,.. 1,,,.., ,ech,, q....Ssess.en, .,,
,.,,,,... (,).ea.. r-., of “.”, ,.”,,. -., . . . or ob, a,. in, ,. f.c.., ,.” ,.,
1976,mtmd,d ,. 6.,,1,,.,, cmaris.m ,.,,,.,. I., o, desig. .etl,c-i..
(a) Hatch . . . ..s ..d . . . . . ..s kt”ee” ,.,, s..,. . . . .Mly,, c.,(b) mck cutmc. ,redic, icm.. W. the Fol, w,.K d’.-(c) CZ! I 8“idee and tra..ver., ,.s.,0” of ,,[,,...,. (,,) (23]
,“,, head s,...,... and .-,,.s ,. .,,,..,” (A) for .“(d) C.”r.l”@r des,m .“.,.. !,.. of ,h, W,., .,.,,.. .(e) Inrer..l ..”,.,”,. . ...0
,,.,,.,., .,s,,.. . n. .“,.,., ..,,,..s .Ea8”red ,,” ,?,.(f) H.bft.b,ltty in ,m...d . . . sL-7 “e.. .bta,md frm ~.d., u...
.,. hm.e. . . ..1...,,... of ,,. @end.,.. ,,6-(8) %ck .nd .h=ll lmdii,, ,. bow ‘i”cd .=... re”t”t err.,., (*,
.,,. dis. u.e.t.. ,. Referer.ce (23) for(h) Ri,ld on-deck .o.t. i.ec further . . ..”....., )
Oe.”. i.c .,.,,.. ,trar..gu,*e ,...,,.”. repre.e.t,d
N. ,..-”,.,,0” .“ me ,.,. “r the .,.,. of ,),. .,, ,“ .,r.,..,.s., ,. G+, a,.cd ,, Se..,,a”d ,. s.”= Plam.e”t with i“,”t. by .0s..,..,,.,,. m me ~encra, ,.,,, = SSC .dv,mm. .“, ~.-,.nd. “owe,,,.., ,),,. Z,W. there 1. .i.,.a, dom.e”,.t i.” .“
th. ,.,,.”.1. ,.””,.ed ,,,,i.. tm.m,!.t’o” ..,..,,0”, ,,.,..=“, , ,U.po.e, a.d 4.,. ,,.4”., ,0”re,. ired. ,t Is, therefore, d, f,,c.,,t. f.!,, ,“.1..,. the ,“.,, -”,..t i.. s,,,.. ,..,., ,., “n ,,= ,,A.,,AMI )kf,EAN w,,,, ,,.,,., (c.. I , )
,,B,,, 4-1 (.”,,, ,d)EVALUATION OF THE SL -7 RESEAnC!4 PROGRAM
E1.m.”t : FULL SCALE,NSTkUIKNTAT,ON ‘
ml 11119 CoiUrlWtLs” 01 th St!MY 1“ AchWlnB It9 SL- 7 WrCh P,w.01 Gea,.sac NO.
R.1. m.Stru.t”<.l D9SI*” U*IM* SFUII (. to th.
P“ W D.t.Mo.s”r.nm”t .nd Pr.d ICI10!! .1 SIIIP R.tlmul WI! Gird.r L.M CClt.rl.
SL- 7 d C.”ttin@,,lIIDS 1“ 00-.1 Lti, UOIIOII .nd St..,, A“.IY.Is and D9”l.Pm.”1 Inch”ltnilStalh.tic.l E“.lu9tt011 ot oat.
C.,nt,r.,.cic.. of bf.?r.nce (1) docme”,.<ion of SWcif,. .bJ.ctive...d r..l.ire.=”t. for .4.,.. . . . . . . . . . . .“d ced.ctio”, TM.lnfocwtl.m,lc .vailab l., -.1.4 b.of ,..., benefit ‘.. fur... f.ll-SC.le L“.tnme”t.tie” ,r.gra.. of ..,.,,., ..,.,.. . . . ex.~le. theInformation could .<d 1. th.d.,e”in. ri.. of .,..1 .-s.”s.i..tru.mt.rio. Place.=”, .Irho.ts.,”8 tbrw%h tk d,llb=..ti..s charw., h.ve taken ,1... ,. decidl”s.IW pl..ement of .tr. i. 8S.S=S . .the WA-MD McLEAN.
S.-7 Instr”.=”t.,io” Pr.8r- . A .ig.tclc.n, f..,..e of ,he te.t . I%. rqort ,l,s= .,. a reeea..h PI.”, . A s’,mif leant fe.,. rc”f the test ,!. ”
B.ck,rm,d .nd U-arch Ph. P,.. ..t Lined in M. ..,.,, ,. chacSSC-257
de”, L.Ped by . few i“div id.. 1. .“d 1. chat ,, .i&d no, tncl.de ,1.”s to
,, d,d “o. I“cl”dt PI.”. !. develo, .evid by the ProJ=c L MvIs!,.Y Cm- d.v,,o, . . . ..1.,. the s1.-7
-1., . . . . (5) ~thod. 1=.. c.mc. imershi, ales,g”. .,t,ee of ,,,. the, ,. or,,nted co.,.,.. rshi, load ..,,..1. or
1976 d,,,c cl, a, rhe valid. tl”” “f .“s IY- =V.1”.t. ch. $L-1 d.,.,1.s1 ,redict l.. t=ch”lques. A“ “v=. sr. tisti..l l,..11 .1!.., of ,1!, ,1.. 1. presented 1“,,..., L-] n,. . . . . . . . ,,.,, for,.,,,.,,<>. v.. very good, b“t wasde,ende”t a“ obtain,”, .“ . . . . . . . .,,cture !mf the wave e.viro.-”t..,.., 1, encti”!e red ,. order to,>bta,n a ..1 idat ,,,. of . ..1.,,..1,.<,,,,,O. . . . . . . . . . . .
I
j-=-+:=<
Figure 4-1
Transfer of Results
Comparisons of Project Results
Optional Comparisons of Project Reeulte
SL-7 Data Comparison
14I———.
!w&f: :1.
n.!. lb.
Pub. ml.
static s,mct.r.l C.libr. tic.”of ship“esp.,”* ,“.tr-. t.-,,0.Sy.,” Ah.rd *h.WA-W. !kLENlSS.-263meter.”.. (7)1976
,,.., sm.m %.”,,. C,- %1,*.,O”K ,m., ,-...,,.2” *WC<,.. SL-7 cl.,. @m,. imc..hiPs.S. SU-IA”. lkLE4. i“ ~ch.,,.”,,. s,”,..S%-264Refer . . . . (8)19?6
TABLE 4-L (c.”, ‘d)
EVALUATIOM OF THE SL -7 RESE&RCH PNOQRAU
E,.nmmt , FuLL- SCALE , “STRIJ71EIITAT,ON
COII1,lbUtb U tin Stud, III MIIWIW Mm SL -7 -,* Pfosmm Qo.1,
tt.”d”,.t 00.1s” U*I hod. SWCllk t. th.
$L - 7 ●nd C.”t.lnu.hlF+ 1“ G.mM.1
m,,,., the c.libracio. ew=ri.mt,1,.,.. de flectim. -,, “.$”r.d . . .,,..1! d . i“m ,o.d,m to i.f.m .r,l. tlmshi, bet.me. h.tch d. fl=ctla. ..+ .e...r,d . . . . . . . . . n,,.hf.-,10. . . . U.. C”1 1. i. f,r.’”* . hatchd,.,,. c..e”, Crm .e...imdudeded.,... -.. ,im” ,-2 f,=, that
Kl”imalda,. . . . p,es,n, e.d ,. ,,, s
-w-; 1. f..,. .“1, . .’.,mal-“m of da,. have b=.” ,e,ju=ed ,0
date. ,h,. ‘, s.b.t.., ia,ed by,.,1. 8-1 pr,...,d ,“ Appendix (.)
Mali, ior..1 da,. r=d.c, io” i. .equ, reberm, the d.,. “.u,,j be i“ . fom“sef.1 ,. . dc. i~n=r ., ,,. e.rcher,
ti..ur.m.”t .nd Pr.dlctlul al SMPLwd. Mci,oII .nd S1...,
, me dam .bmimd fro. the c.1 ibra-,1.” ex,erfae”r “.. u.ed to aid 1“the ..1,...1.” .[ the ,0s fi”[email protected] ,r.we. MISY. m. ds”-,...,0” of ,h.t ..,.,, (Ref.,...=16) P,.*.,. . . .“.1..,,.. or th.c.lib.. tie. Uperim..t . ...1...
, m,. i. .,,,.,1, . d.,. for..,
w..=.,., 1.. r.P..t. n. ....,resented i“ the w,.,, ,. n.,co., r,but. ,. “.1 Ida, ire,, etf..,..
R,tlan.1 Mull GM., L.M Ctl,.,,.k.1,.l. .“* Cm,., op.n.., ,.d.J*,n#
St.tk,,c., Ev.kmllo. 01 O*1*
s- of the *.,. Pre,.ntdi. lb ,.,0,, . . . orientedm“.,d .t.ti.tk.l . ..1...,0” of,.,. (s.. F,*.,, ,-9 .1 ,h, s ,.,0,.,.H..,,.,, the da.. th., ,,, Presemtedatai”st Beufor, Number ,.. i.cc.m-“,”1.”, for valid., ion us,
I
Condi tion
4
4
4
4
5
5
5-
5
6
6
6
6
Direction
1-1
2-2
3-3
4-4
1-1
2-2
3-3
4-4
1-1
2-2
3-3
4-4
Measurement
96’ 4 314”
96’ 4 9/16”
Sfj, Stt
50’ 4 114”
96’ 4 518”
96 ‘ 4 5/8”
50’ 4 314”
-*.
96’ 4 318”
96’ 4 15/16”
50’ 4 11/16”
-*
‘i
.CumulativeChange
o
0
0
0
- 1/8
+ 1/16
- 1/4
-*
- 318
+ 3/8
- 5/16
-*
HATCH 7
‘Ort’E3Els1 3 4 2
*Reading not taken due to safety considerations.
Fizure 4-2 Hatch Deflection Measurements from the Calibration Experiment–-Perfonned on the SL-7 SEA-LAND McLEAN
15
~.
f
TABLE b-l (.o. t ,41
EvALUATION OF THE SL -7 RESEARCH PROL? RAM
Ei.m.”1: w .. ......... ......,.. ,-.. ..?.,.. ”..”... . . .
RsP&::)1. Cw,l.ihtl.” 01 III. Stud, 1“ AcM.”109 thOSL - 7 M.”.rch Pro#r.n! OMI.
n.!. no.Pub. mm
Str”ctuml-910” U.thodS SOdllc t. III. Mo..u,.”.”t .nd Pr.dl. tlm .1 SMP R.lton.1 M“ll Wd.r L..d C,tlwl.SL - 7 snd Co”tdmu,hllIS 1“ Oatmrmt Lc@, u.,,.” .NI S0,... A“.1”*,. ●nd m..l.pm.., Ineltim
S,.,,.1,..0 E..hJ.ll0F7 01 D.t.
SC..., se...” . ..”1.. fro. . .-., s pr..e. t.d for Refere.c. (8) . c-.,. ,re.e”td for R. f.re.c. (81 . C-.,. . . . . . . . . . for Rerer..ce
ship n..,””.. 1“.rn”e.r.tie” .PP,Y. .,,1, . (8) .,,1,.A,.,.,. the SL-7 .,.s. Co”-C.lWC*l, S.s. SM-IJND WLm. . m,. were record,, “ilile the,“ Worth .,l.”c L< %,”1.. “CLCM “., s.,,,’ “. .“ ,6.SL-7-9 block. d.ri”, drydu.kim,. Ho”.”..,WI.,,... [9) this ‘“formation h.. ..,, bee”,976 a.aly.ed.
.
.
C-t..,,1,.
for me fer.”c. (81 . c-.,. ,ree.”md for me,,,,”<.(8) .,,,,.
.
r’-’”””I
.
TAB!., 4-1 (c..,,,]’EVALUATION Of THE SL -7 RESEARCH PROGRAM
.,.-. -.. . . . . . “ . ..- . ..-..—. —.. .. .... ... ,“,,. >.-. ,., ,...m,a,, o”
m-t ml. Cc+, ,Ibt Ion ., th. .%.d” 1“ ACII,.W,W UN SL -7 R.,..rcl! Prcq,.m GM,.9SC “o.
R.,. No.
P“h. 0.,. StIUCtU,.1 CI..t,” M,thod, Sp.c,,,. ,.,11. U..,”,.OI.”1 .nd Pr.d#C1lO” .1 ShlP R.1lc.n.1 11.11G,,d.r Load C,,,.,,,SL - 7.Ed CO”,,,..,.II,O, In O.W,., Load, “.,,on ●nd S,,... A..ly .,. ,.d CWV.,OC..W.”, In<,ud,w
St.tl.tk.l E“.lu.t,on o, D.,,
0,,,, ”,, ,.,., . . . sta”,iardIU. k.r . . ..me. ec ,,., ,On,.,nec.
. References (M) th.o.8h (22) ,,.s..,data red..,,.. ,,...,.,,. . . . ,h=
S,,’, w,. Reduction .ti,.,,.,.,,.” ,.,,,,, $.b.e,.e. t da.. reducrio.s. The
,,s..ss,.. ., the ,e.”, t. .Ppeare ,“SC-277 b’..cece <,,, ,978 ,. f,,e”ce (23) w+,,ch ,s di.cussed“..e.a, er “.,. ,e.i. ct,on &,l,.d “.X ts.d ,.it, a, m,. . . . ,,. s,.,COn,a,wr.hips,,-,,, ,Cf.rcn., (,5) ,9,,
,.,.. and ,..,,, “aveEter O.,=f,m s.,. ,EA.m, k,~:
“.,... 32,L-7-,6 Refer.,,.. $,6, ,9,8“.ya*e 33 -sL-7-,7 “,c.,,.c, (,7, ,9,8“.,.,, 34S!-7-18 Refer. ”.. (18) ,978“.,.,,. 35 ..d 3,,
SL-7-L9 tif.re.ce [19) ,978
Msdif,.d ~d. r amd ,,...4..,,.,kcr “av,.eter s,-, c..,.,.,,.sh, p D.,.S.-7-2. mef,.,..e (20) ,9,8
lad., and ,“cker “..=,=, h,.f,- s.,. SW-w Ibl.KAll:
voyage 60,,-7-2, mefere,,ce (,,, ,978v.,.,. 6,
S.-7-22 Refer,n.e (22, ,978
>. —.rI
Rwmt 1111.$8C,10.
n.,.No.
Pub. O*,*
U.. I,S and ,,.,..,,.. ., che,L-7 CO.,.,.,,.,,, nad., . ..4,“cker “.”-,., Ml.s,.. ,80,.<,,, ”.. (2,,1978
TAD,, 4-1 (ca”c,d~
EVALUATION OF THE SL -7 RESEARCH PROW(AU
,,.m.., , ie!JzL-scALE ,N,7WJ?IEN*.TIO”
Cont,lbullca 0, ,h. SUM, In Achl.v,nq tln SL-7 R.”,,ch P,ow.m r30d,
Str”.t”rml 09.1s” U.th.d, Spaclfk t. th,
SL - 7 ●nd C.”,,, n.,shlp, ,“ 9.”.,.1
M.m..r.ln.”l .nd P,.dktl.” 01 SIIIP
L..., Uotlen .nd Slr.s,
. Ihla .e,”rr c.ntsin. . detailed de.-..,,,,.” .“.3 ,“.1.,,,.. .91 th. wave-me,er .,.,..8 “S., .“ the sM-LANC“cI.FAN. me ..111 . . (..1.!11) ,.,,,.,,,.,.,, co.clud,d :
,Yfw e.,de..e SC,..,,, ..,,,.,.,h. t ..,,,.. ., ,,!. ..”. .EWJrin,.,,,..s (Tuck., and R-4., ) c.” bere,.cded as . .t..d. rd by whichthe ,er, omme,of ,!,1 .tl,er ma,be judged .,,
T,,. i. l,l.atrar. d b, ,,,,..1 com-,..,...s of . . . . . . . . . . . . . . . . sham i. . . . . . . ,-, . . . 4-4. m. .“”’$),!s10”6. . . re.mend. tie.. of Refer? ”.. (2, )
P...t. t . disc... i.. of hm. t..
.rwrm ,rtsmced i. section 1.1 ..s,
.,,.,, ,.., ,,, ,0 ,e.,”m *“C, v., ,,.-,,0.s.
R,tlon.1 l+vll Glrdw L.,d C<lt. r,.6..,”.,. ..d CM,.1.P.n.nt InCIUd,,lsSt.tt,tl..l EV.lu.tl.. .1 Dal.
50-
++/
* 4@ -++++~14.
TWKER ~TER ; 4 FUW ( CCRRECTED) , FEET
Figure 4-3 Comparison of RMS Estimates
from the OWHS Radar with
Corrected 4 RllS Estimates
from the Tucker Meter: All
Intervals
TUCKERPETER : 4 131S ( comfCTED . FEET
Tigure 4-i4 Comparison of 4 RMS Estimates from
tli.5OWWS Radar with Corrected 4 RMS
Estimates from the Tucker Meter;
Intervals Plotted are Restricted to
T hse for which the Radar Spectrum
Area above the Low-Frequency Inte-
gration Cutoff is Greater than
80% of Total
I
R.m,l Ttto.Ssc NO.n.1. No.Pub. D*I.
mm. ,-1 [co”, Id)
EVALUATION OF THE SL -7 RESEARCH PROGRAM
E,.,n.., : ,“,,- ,..,, zNSTRUNENTATION
CO!! M8M1O” 01 II!. Stud” 1“ tihl.”!w tMSL - 7 R.,..rch Proor.m G..ls
,,..,.,., C4.,g” M.lh.ds Sp.dll. 10 m.L-7 .ti c..t.tn.r.hlo. 1. G.--l
,..,u,ur,..t and m.dktlon d Shb
.0.4wit,.” .rdSt!...
The .“”., ”=,,,.s by 01’”.. (net. 31),.,,< .,, t,., ,!,, s.r. cch 8.””.
,=,. .ay be “se, i“ . ..1”..11”..’,, ,.ad. c<,.b,”a,i“. tech.lw-,. ,,,,.,. ,r.b.hi, i., ic distrl
,., ,... ., crd,n.d loads o“.,
,),. 4.,<,.. recording,a~i~.,.,..,,,,., i.. ., ,h-e xr.tch-,“, , ,,,,,,.I ,X,ert. ”.. (..”,~)
I
b’
11.P.rt Till.SscN..
n.!.MO.
Pub. O.t.
. . . ..”...,0”of.eferen.e(111
T,BLE 4-1 (m”, ,dl
EvALuA710N OF THE SL -7 RESEARCH pROQR&ii
E,.m.., , FULL SCALE I“sTwRIEaTAT ,ON
tilrlbutlon 01 MI. Stud, In Achi.”ltta lb SL -7 FI.”.rch Prcqr.cn Goal.
;,,..,.,., D.,1.w M.thod. SII.dflc 1. lh.
IL- 7 .nd Cent.in.r,hlrm 1“ G,Mr.1
a......nl.nl .Od Pr.atotlo” ofshin.wd, Me,,.a” ●d S1,..s
1.
,.
3.
,.
5.
s,,ll -”.,.. bend,., due toweishcand . . . . . . . . .
Bend,”, due m the shl,, 8 .“7!
wave ,,.,. .
“a.e-i”.d.md be”diw.
m..mi.1.=,.. 1..,.,,”8 .1-=,.8“h,,,,., and .,,,.,, ”,.
,hemcl effec t..
il.tlon. t Hull Gird.r LoM Crll. rl.h,l”.i..“d D.”.1oo.T..”II“cludinsSt,,,,,,.., E..lu.tl.. .1D.t.
FWOURCE-STBD
DATA YEAR 3ATLANTIC
SCRATCH GAUGE BS7_
%080z 50
0
12Zm
,14,8
WMMARY
DATA YEAI? 3
PACIFIC
SUMWRY
CMTA YEAR 3
ATLANTIC
Y -037
-
6z
to , , 1
0MAXIMUM’”PEAK ‘:0 T&OffiH %REsm- KP%
40
II25W
20XJ
SUMMARY-TOTAL
DATA YEAR 3
.,..,62r
Ezl#
r
MA?aMUM’OPEAK’ ?0 T&GH 2~TRE%w—Kp34
tw
Figure 4-5 Histograms of Scratcl,-Gauge Data Measured on the SL-7 RESOURCE
Paper Tape Record of Scratch Marks
k:”:” - -, n-,-
I---xl--xl.1IIII
I-T” m.~+++
t“-- I \
\
\\
\\
-.
\\
\
\
II
//
//
.-
The trace of the scratch
gauge recording pen isoften visible as the
paper advances every four
hours. The trace does
not necessarily arriveand leave at the same
point on the scratch.
ILApparent
single ex-
treme sag
J excursion –
1flare or
bottom impac!
Range of moat
wave-induced
strains and
mean loadingvariations
Evidence ofextreme hog
excursions
Character of the
scratch marks in
severe conditions
Figure 4-6 Miscellaneous Details of Scratch Records
24
TIMS HISTORY OF STRESS
Maximum Posit ive Peak:
Transient Stress From
Flare Shock h Wave-
Induced Load
i! f
Mean Stress Change:
Thermal Loading
Maximum Negative Peak?Green Water Impact
Figure 4-7 Illustration of ScratchComplex Time History of
SCRATCH GAUGE
~Rii———
Equivalent
1
Scratch Mark
LMean Stress Change:
Ship Changing Speedand Generated-Wave -
System Loading
Mark Equivalent to
Stress.
TABLE L-1 (,.”, ,dl
EVALUATION OF THE SL -7 RESEARCH PROGRAM
.=1.m.”! : mom TE,,,nu ,. . ...”...
R.r,., t 1111. Co”trlb+llon of th. Stud, 1“ Achl.”lnq lb SL - 7 R.u.r.h Proo,.!n Goal.Ssc N..
n.1. m..
Pub, O*1*St.u.tur.l O.*ICJ” U.thodn Sp.cltlc t. III. M. . . . ..m.nl .nd P,.dl.tlon .1 SW R.tlo”. t )4.11Gird.r Lo.d Crlt. rl.
SL - 7 .nd Con,,ln.r.hl P, ,“ G.n.r.l L..d, hf.tlon .md Str.S. An,l”.i. ..4 D.”.l.mn.nl $.cl”dlwSt.tl.ti..t E“.lu.llon .1 D.t.
,... Lads i“ a l!odel of the . ,he .es.lt. .[ the (...,1) l/140th,,-7 Con, ai.er. h’, Run” i”, a. . ..1. model ,.s, s of the SL-7 c.”–M,,,,., “e.d,n,s i“ Re@l. r !a’ner,h,, were . . . . ,r,msr,,y t. aidl.ve. ,“ ,he v.l,dati.n of the sCORES;s, -219 COmp.,er ,ro,r a,. ,..,,., ,,.,..,,..
k,ere.cc (21 of the mad,, ,,., ,,,.l, s is Pre-.,74 .e”ted ,“ ,,, ,..,..,,.”. .,1
RCfere”c.a (4) ad (12).
. ,,. mode, w.. mall and se,’-C..tmi led s... ,..,,.., ..,, e.-cou. tered with. ,,. direct imml . ...,.0, the .C. &,; however. ,, . . . feltby c,. ,.”,.,,,.,... that the dlf-,,..,,,.. .,,. of .ecmd.ry concern.
. . . .
27
.
rr
28
M Gages %+-sible in this ‘iewo Gages hidden in this view
+ Rigid Vfiyl Model Stress0 Steel Model Stress
Figure 4-8 -Comparison of SL-7 Stresses
cluri.ng Positim Torsion
29
I400
J-LOADS(Lss) SUPPOR1
SHEARF017cE(LB$)XI03 -,
5ENO~NGMoMEm-
(:s-4
3
E
Ah A
o 1100(2) 22(2)
goo
300
_LILl(4) (2) @22008090 I
I&iAxmi AmAnrMl
f
G7—
0(4)
3000
800
-50
4Y,54L3_34,!<0 ~
i5,0GO
Date of Experiment 6 July 1972
Figure 4-9 Representative Loading AppliedSteel Structural Model
—
(2))
SUPPORT
7{0“00
J-1000
to the
30
L._
. .
31
!’k400 500
Figure 4-10 Hatch Distortion vs. Stresses inTransverse Box at Fr. 178, port Side-Section B Due to Torsional and Lateral
Moments For the SL-7 Containership
32
k--
MAIN DECK MAIN DECK
wu
,.. /4, 1’
Mli-l●a.#4’
1t-e! --------- ,
---------
--------
‘.
STRESS SCAL.f;
: — LONGITUDINAL STRESS
--- SHEAR STRESSt I ~,,=4mt,4,,veR1waLMem,#Jr.,t~,z,t.-
t swaa~peats..*I *...
1
F“. /4. I JR ,4’
l ----------
,,
:,
.,
,.
,’;, I
III
1
I
S7RESS SCALE
q-& “
— LONGITUDINAL.STRESS
--- SHEAR STRESS47PmAm. ,4,:LATERAL MomcMr . Z6, SO0 1--
mastemAL momENr. 17.000 *. ~
LA TE*AL SNSAA . -700 tO*S
Figure 4-11 Stress Distribution Due to Figure 4-12
Wave -Induced Vertical BendingFr. 142-146 Second Loading
Case
Stress Distribution DueL“ateral Bending and TorsionalMoments Fr. 142-146 SecondLoading Case
uc-
*,1 1111.SSC No.
n,l. N..
Pub. m,.
TABLE 4-1 (cmt)d~
EVALUATION OF THE SL -7 RESEARCH PROaRAM
.,. -... . . . . . . ...! . ..”.-..-.!.”... ! ““”b. ,.— . . . . . . . . ..-
CuItrlbIIth of Ih. Study 1. Achl.vi!m lb SL-7 R“..IcII Prow.m God,
struc,u,. t D..ls” hl.th.d, Srmclrlc t. lb U..,u,.m.”t .nd Pr.dl.tlom of ShlP FI,OIUUl Hull Qlrd., LoSd Cvlt.,1.
SL - 7 ●nd Cent.in.rsh,P, In 0.09,.1 L086, Mot,.” ..d St ,..s A“.lY,I. .M LM”.1.r,.n.”t I“cl”dlwSt.1lntlc.1 E“.1”.tlca of 0.1.
,.,. bad. .“ me SL-7:..,. i.emh,, i,,k,.,., ad,rFe,u,.r *SB,s,-246,e:er.”ce (G)197&
1. ,“fluenc. of hi8her forward weed., ,!,, CO”tai.e.,h,p (,.0.,,
““.&r effect).
2. *. ,“,,0”,.. . ..8. 0,. ,!,..,, ,..omidered to be very ,..,.,,.,,.. ,. rhe ,.” ..,..,,,,,freq.e”cie.
3. Lateral ,1.., ..”. . . . . . arehi,h, y de,emdent .,.” .dequa.,,,,..s..,.,,..of.,,,,,01,. . . ..”s. .,,. .O.-,, r,lsr ,.,,dam,,,,,, “hi., ,. . . . ,,, . ...”.,,11>. linear/.bi, .0,’0”. ,m,ra..
r
Vertical Moment AmplitudeWave Amp litude
Heavy Displacement
1Ft.-TOI?s
50000 ‘t “a
0°
e Experiment (V-30 KTS)n Experiment (V-25 KTS)— Theory (V=25 KTS)‘-- Theory (V-30 KTS)
40000t
30000
120000-
10000
}
(-.,
D\
r \ 0
I \\ .
I \.f <0
\A/’ ‘. 8
/ ‘==.
/
[ I I I I I Io
I I I I.2 .& .6 .8 1.0 1.2 1.4 1.6 1.8 2.0
Wave Length lShip Length
360G
~ 270 t
j 90 -A
I IQ ! ,-s1 ? I I I 1 do .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8 2.0
Wave Length /Ship Length
Figure 4-13 Midship Vertical Wave Bending Moments and Wave
Phase Lag, 180° Heading
35
Vertical Moment AmplitudeMave Amplitude
40000
30000 t
Light Displacement
o !lxperiment (V-25K’I
caExperfment (V-30KT
Theory (V-25K’I
--- Theory (V-30K’I
‘L_!?Qss.4 .6 .8 1.0 1.2 1.4 1.6 1.8 2.0
Wave Length/Ship Length
3601-$
n 270
G
1 180 –Q11%s 90 -P. 0 00
I I I I I 1 I I I0
0 .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8 2.0
Wave Length/Ship Length
Figure 4-14 Midship Vertical Wave Bending Moments and WavePhase Lag, 0° Heading
36 k.—.
Heavy Displacement
OExperiment (V=30KTS)
oExperiment (v=25KTS)
Theory (V=25KTS)
–-– Theory (V=30KTS)
Torsional Moment AmplitudeWave Amplitude
Ft.-Tons
IFt.
5000
t4000
tn
3000
I I I I I I I I I I 10 .2 .4 .6 .8 1.0 1.2 1.4 1,6 1.8 2.0
Wave Length IShip Length
360 -G
: 270 -
G
~ 180 —$ ~
z 90 –B.
I I I I I I I I I Io .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8 2.0
Wave Length/ Ship Length
Figure 4-15 Midship Torsional Wave Bending Moments and WavePhase Lag, 30” Heading
37
5000
4000
3000
2000
I1000
Torsional Moment AmplitudeWave Amplitude
Heavy Displacement
Ft.-Tons o Experiment (V=25KTS)
Ft. _ Theory (V-25KTS)
o
0
“L 000
[ I I I I I I I I I Io .2 .4 .6 ,8 1.0 1.2 1.4 1.6 1.8 2.0
Wave Length /Ship Length
360 - Cl QG ~
8 270 - 0000
G
2 180 –~
2 90&
I I I I I I I I I Io .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8 2.0
Wave Length/Ship Length
Figure 4-16 Midship Torsional Wave Bending Moments and Wave
Phase Lag, 240” Heading
38
,481,, 4.1 (W, c,d)
EVALUATION OF THE SL -7 RESEARCH PROGRAM
E,.m.n, , AMAL”T,CN T,aiN,Q”Es <
R.o.,, 11(1. Cc+trlbW.m .1 NM Study 1“ Ach,,”lw lb SL -7 Rn.arch Prwr.,n Gem,.Ssc“..R.,.N.. St,”.tw.tD9.lgn M.th.d, SD.., !,< to #h.Pub. D.t.
M..sur.m.”t .“d P,.dlC:lO” .1 SiIlo Ratio”.1 !4”11Gird., Load Crl!. r,,
SL - 7 ●nd Cent.,n.,,h,p. ,. G.ne,., L..d, Motion and S1,..s A..l,,,. ●nd D.”.l.aPm.n, lncl”d,rqSt,tl.1lc.1 Ev.lumtlo” .1 0.1.
k . . ...)..,.. ,tud, of sL-1. . . ..i.. rsh., ,.., s a“d
. This ,r.]e. c extended the b..,. c,.. r,
mot’.”. w,, T,.,. .“.4,r..e”ced ,. ,e,ecenc, (4) in several. . . . . .i, icb include:
-“C.. SI..l.c i..SSC-271
1. ,n..r,or.t’.n .1 .,... -’,,
Ref.,,.., (,2).e.h,,’q.e. f., deve,.,pme”, .,
1977,Y,r.dy..m,< .mff,c,e.t. ,.sc.adof the ,..,. <... .e,, ed.,,, ,“., 1, e.ployed
2. ,“...,.,.,,.. of .Peed-de,ende”r,Em ,. ,,, eq.a, i.,”. of m,,.”.
3, ,“,l., ”., .’ rudder ,.,,..,,.” inchip .,,..,.,., .,,,. ”...
4. ,“c. rp.rat,o. of ,,, .* ‘,.,. ofWI,, i. the . . . . . . . . . .{ m,,...
5. r . . ..tt*.n*.n ,.,. d,. eccecc. of. ..-.,”,.. c.,, in .!,,, .<.,.. s..
EK..P1e, of the i. C1.e”,e of ,.., .1these ..,,. s,... t. the ,.0,,$ the.r,are ,r. sented 1. the r.,..,. s=veralof the figure. .(. . . . . . . . . . . . ,.,.and ind,.., e .“ ,., ro.e.,.t L. ,red,c-,,.”s for ❑’dsh,, vertic.1 bec.i,., .“d.Id.lsi, c..%1o.=1 bemdin,, (-e,,,.,,. &-,7 throush 6-20. )
. me effects of mdel ,..,,., !,r.c.-du,es cm”.md.l ,.s,.”s. were ,.d, c.cedand “(m,, b...,,, f.,.,. .“.,.,, s..sb<s”eem .*.1 tests .“.i the.. !,, ..1Predicc*o”s. A. a ..suIc. (.”n<L)
[,”’
40
I I I I I r.1 . . .5 ., ,,, ),, ,,, ,!6,:**!O
HAVELINGT”/S”,P LZ.G, ”
160 —~
DE.
210 .
180 —
{;: N: NM
90—A
A,
I o fA
I f 0 I 1., ., .6 ,, ,,, ~,, ,., ,,6 ,,, ~..
“AvC L,”C, W&”, P LCWT”
Figure 4-17 Midship Vertical Wave Bending Moments andPhase Lag, 180° Heading
%5H?”m”” PlstLKclwn
1u 10 XT. “C*W Dls>,x,.cm
vt. TICAt .0.!6.1 A“. L!l.DE A 25 XT. LIGHT OISPLACE R-I“A”t NV, I TUoc If ,0 F.,. ,,.”, (I IS, LK,W18T
[,m o ~:
CJ#w.$0& /;;;:.”.
‘247, o
.0000
t
99L /
Figure 4-18 Midship Vertical Wave Bending Moments andPhase Lag, 0° Heading
42
l“R,!CAL“0?!04, ,“., , WOE“A,f ,., L ! ,“.,
W“,Av, OISPLAC,,W,U]o .r. MEW. OIS.L.CS.C.,
A ?S .,, ,,.., .,%, LAcE.,.,
S*MO
t.
U#?s
Zf>or.r. ,,.”, Drs,LAcc.c.,
[
2$ CT, ,,.”, m:~ls r.T “e.”,
,*,8,
tJ**M l--
I I I I I I I I I.2 .* .6 ,, ,., t,, ,,, ,,’ ,,8 ~:e
MAvc LV16,”,s., P LCw,”
160
t
~DC..
Figure 4-19 Midship Vertical Wave Bending Moments
and Phase Lag, 30” Heading
43
3000 -d
A0
,00, — 0-,0 .,, ,,, ”,
2, K,. .,.”,
,0,0 . 10KT. HE,””
0
I I I., ., .6 ,8 ,,0 I, I I,..,. I.,,, LCw,.,$.; p ,,.,,”
1.8 .0
~
F-n““ “’”>-’’’’’”’8”>,,4 00
4—-25 K,. LIlj”,
,80
I \90
t[ I I., .. ., ., ,1,, ,), I I I I
.. .. L,WT”,;, ,, , ,“.. ”, .8 >.0
Figure 4-20 Midship Torsional Wave Bending Moments and
phase Lag, 240” Heading
44
s-Ln
R.r.o, t Tltt.Ssc ?40.R.,. No.P“ b. D.t.
,cru. tur.lAnal,.,. ofa. . . ..imemhi. ,,,.1)!.,d.l and,.m,.r,,m with theTest8...,,0,.l . . . . . . (30)tive.ber 1976
TABLE 6-1(c..,, d)
EVALUATION OF THE SL -7 RESEARCH PROGRAM
E1.rn.”t : ANALYT,W PREDIC11ONS
C.mlrtbut lo” of Ih. SludY 1“ Achl.vlW tMSL - 7 R....rch Proor.cA G..).
S1,”.1”,.1 D.diln U.thod. S...411.10 th.
SL - 1 ●nd C.nt,h.,,hl P.,.G.n.r.l
.
.
.
.
standard b,am-cheery ..1..,.,,... ..,!
,“cluded,“ the . ..1..,. for,.rebend,., “,.,,..1 and awe.“.11..“.,u M be .x,.<ted The vercimlbe.di.g ,.s.,..,..”. are d,m i.F,*”,. 4-,,.
NO be--theory c.lc.bti...“ereincluded for<he ,., s’...1 L.adln,..”.s. Tk ,..”,,. “o”Id h.”.
m ,;d,=tme ,.,..,, t.r.,or.a]re.-
,..s. .f m--d~=k.d .,1P= .I. -wi~.
l%. r,c-”dacim, ,m.e.ted 1“,,,,, . . . . (30, ..”,.,. valuable .esl,ns.,,,.,,... that were .bta,..d from,,. f ,“,,. -.1.-”, .“.l, s,. n).re..m.dati.n. . . . re, r.duced ,. thesum,, of Referem.e (301 ,. .,,,ndix(A)
M.a.ur.m.nt md Pr.dlCtlO” ofShipLo.d, Motion ..d Str.,,
R.tlon.l H“IIGird.r L..d Ctll. rlaAnal,,,, .“d D.vdom,.”1 1“.l”dlwSt.11.lb..oEV.I..lIO. .1 0.1.
(d)
(-1
\I---
~ HodelTestResultsFinite Element Results
— - BeamThe.wy’
(e)
!i-J,,( 1.,Iy!
R~,~..——
+) (+) /‘,, J“
[+1
(-l
‘\.---FRAME 10 I
0246019
IKlrsw+
Figure 4-21 Comparisons of Structural Model Tests and Finite-Calculat ionsElement
Loading
for the SL-7 Container ship,Case 1.
46
.3 Rigid “,.,1 ,0..1
(.) bngfludi.d S(,OSI
.
..,4., ,... ..,.,,,
(cl Lo.situdi.al st- b
{-)
P(-1 - (-,
(-)rm.”, 2,,
,2.4,10
I,!,, ,,~
(b) L.mgit.di.d xtrm
lb.., 7... *.,.),,
,’.,,. . . . . . . . 1.,.,,,
.
4
a,R#n, ,,6
,? 4,,,.
/r,,, ,,~
(d) L.mgitudiml st,eM
Structural Model Tests and Finite-Figure 4-22 Comparisons of
Element Calculations for the SL-7 Containership,
Loading Case 2.
47
i“””
TABLE&-, (co”r~.
EVALUATIOM OF THE SL - 7 RESEARCH PROGRAM
.,.,”.., ANA,.YTrw ,$X., CT,ONS
R.wrt 1111.Ssc “..R,,. No.Pub. D.1.
Cont<lbut1.”.1 th. Stud, 1“ Ach,.v,rq tin SL-7 FI.s..,ch Prcqr.m G081.
StrU.tUr. t D..lgn M.ttwd. SP..U,I. t. ,h. M...nmntnt .nd P,.d8.?tiO. 01 ShlP R.tl... t Hull .31,6., Lo.d Crlt.rl.SL - 7 .nd C.nt.l..rshlo, In G.nw. t L.a.d, hl.tl.n .nd S1...s An.ly,l , .“6 c!.,.,...r,l,1 Includ,rq
St.11.tlc.l EV.IU.10.. .1 B.1.
eis”’fiea”tC<,C;,for L,e.,,.,,.,., c., ibr. cio. wert incx”t,. s,v,.“.l, s, b., the ?,,.,, ,“,., ”,, ,. b.c.uw of .,*”,,,..., ,,.,.,s,..,,.,s ,,,, of .,,s,,s,s . ..., b. ,,.. .4’1,.,..,,,,1.d.,,., the ,,., andh,bic,ve c., rout,.. .,.,,,.,,.. at ,.. .s,.,,..3.. of .f.,,,ed loads. m,,,,,, ,“,., ,“ ,,.,. “’W.. =,, ,,. .,s” mc-.d.d ,h. c ‘or ‘.,.,. . . . . .,tch”,que co.,,i b. e.,, eyed ,. ,.,.,., .Cql., e . . . . . . . . . . . ,.,. b, Ie. o,dda S,.,,,,,., .3,.,,” ..,.4 ,,., ..u, d ..d,,.,a,prle,ab,e EC!,..,,. *be “me., ,0 d,,, ,. S,*”.,S. s,,. *“S be ,ener. td ,“ cl,, S,,.. ,.,.
I . A m.dif,ed vets,.. of ,,. scows I
. The Com,arimm ., .e.s.red S,.,... . . ,red,., ed ..,, s. . . ..vcr.hado-d by ,,. ..,,.,,,,,, .,r.ll- scale “... . . . . . ,,9.,. s ,.2,. ..4.24 silo” ,,., ,,. ..”. ,.,.
,,,.,...4 Imdi, ita,,..be,.,. ,, m“,,be wed s. ,... t forthe ,...4 DrI-
I
I I
49
,.,., 4-1 (Co” t,u)
EVALUATION OF THE SL -7 RESEARCH PROQRAU
,,.”..., , ANALYTICAL ,Rm,m, ms
IWQr, Tltl.Ssc“o,
R.,. M..
Pub. D.,.
,..,,,, ”.,,.. ., Refer..., (?61
A T’- C.,.ai. sol.,’.” ,. the
“Ovabe , ,912
Cmtrk.utlm et Wm Stud” 1“ Achlwtw lho SL - 7 Re”mch Pmwmm 00,1,
Slruclur.1 D.slm U.th.d. SPClfk t. m.
SL - 7 ●nd Coml.lm,.hlrm I. O.n.r.lM.a,ur.m.nt and Pr.dtCttO. 01 Ship
Lo.d, UOUO” .nd St,.,,
m.ditio, w.“owver no directcm,,aria.n, b,,..ae. .cA1 and.Umlric., .I-”1.t 10”. are ,re-.ented for . .. . . . ...”.
R.llO”. I !+41 Gird,, Load Crlt.,1.
A“.ly .,. ,“d D.”.l.mI.nt 1“.l”dlrmSt,tktkml Ewmiuatlm .1 Dal.
[’””
Figure 4-23 Comparisons ol the vave time history measuredon the SEA LAND McLEAN and the regular waverepresentations (Condition 15 - Voyage 32W -Tape 145 - Index 18 - Interval 5 - Run 405)
.. r:
Figure 4-24 Comparisons of the wave time history measuredon the SEA LAUD McLEAN and the regular waverepresentations (Condition 16 - Voyage 32W -Tape 145 - Index 29 - Interval 50 - Run 450)
5i
+12
1lhnlP WR+lcumbit mss
ii”.,2
a . )0 !1 12 13 14 Is 16
‘rrhlc w. “Es
Figure 4-25 Comparison of the ciiiulated and measured meanmidship vertical bending stresses (Sensor LVB) ,Wave Condition 15
9
.910 11 12 ,, ,4 ,, ,, ,,.
Figure 4-26 Comparison of the calculated and measured meanmidship vertical bending stresses (Sensor LVB) ,Wave Condition 16
52
Lnw
R.F.ort Tltl.Ssc“..
Ret. N..
Pub. n,,.
1979
,.,,, k-l (e. nC, d)
EVALUATION OF THE SL -7 RESEARCH PROQRAM
.,..”.., LO.. CR,TZR,A. . . . —..—-....—.
Cmtclbutlo. .1 MI. study 1. khl.vlno lh+SL-7 R.”.rch ProW.m Gc4.
Slructur.1 0..1s” M.lh.dm S...111. t. th. M..sur.m..t ..d Pr.dl.tl.n of Ship R.tlo..1 null G!#d.. Lr..d Crll.rl.
SL- 7 .ti CO”l.1”.C.MP, I. G.n.r.l L.a.d, Motion ..6 St,... An.1y.1. .nd D.v.lc.wn.nt I.<I!MIIIsSt.tt.tio.l E“.I. *11.” .1 0.1.
. A ,..,, . . . . . . . . . . . o“, limed in this . L“ the 1“scu”E”,s.,1o” ,r.md”re, the,,..,” gauges ..,. . . . . . t. . ...”,,1.. to e.ch de,.,,.,. wlch mrecord k.,, of the off-t. m..,initialme.” . . . . . . ,Ofom.tie” . . .10S, I!I. lack ofthis I“f.”atio”,r.”ed t. b. a II-,,.,1.” ini“cec-pce,,”g ,,. . . . . . . . .=.e”red . . theMcL!AM
..”, -,.,..,, .,., . . . . ..d h,,b-
[.,,”,”., wave-induced stres s..,., . . ..’...,.,. m 1.,18”.. ...,;,,
. The S,.,, .X.. i”d .“.4 .Va,..wd.,..,., .,.,,., ,..1d,.,, ,b. ri.”s
-c-,1 Tltl.SscNO.R.,, lb.Pull. D.,.
.0”,,,, ”.,,.. .’ W*,...,= (3,
C“a, ”a,,.n ., ,“,,.,..,,“.”. LOadgReference (,4)
TABLE ,-’ (C.nc. q
EVALUATION OF THE SL - 7 RESEARCH PROGflA”
Elenw”t , I-W CRITERIA
CC@ribu,l.an 01 (h, Stud” 1“ Achtw,nq ,hSL - 7 W“.,.!! P,m,am Go.,,
S1l..l ...1 D..la. M.th.d. SP.WIC t. u,.
St.- 7 .M1 Cont,ln.,sh,p, I“ Q,lm,.,M,.su,.m.mt ●nd P,.dlctim .1 ShlPLMd, “.,,.” ●nd S,,,,,
.
R.tl.”.l !+”11Gird., Lo.d Crlt.,1.
A..W. ..d D...lopt..t hd.dhwS1.ll .11.,1 E“.1”.llon o,D.,.
.
.
—
NO ,, fe-t,w ,O.d. “e,,
n,.,.’.,, ”., ,,, =”,. da,.
I“di.ati”s trmd. ,. A,, bmd,.g-.,. ,nfe, red ,1* ~.oured
strain.n,e ,.,”.4s .,. ,.. s.”,.,
f.r“sri.”.shi, !,,.. (,..,..4,.sthe SL-, ) . “?a,l,er .“=”””,,,.,,,,..4. . . . . . . . . ..4 ..,,..”, h“,,Par-te r.. m,. . . . . . . . . .. ..., be Wef., ,.. ,b ,=.,,”
.f .I.ilar ship., howcv, r. ,,,d.c. ,,.s..,..4 .s R’,oc *A”
SW.r= MS d.,. with . . ,,,,..p.,.,,.”. ,. ,,,, ,- ,,,.d. .,de.,,. ,o.d. . . . . . . . . .
I
4.2.2
4.2.3
The three load criteria studies (32, 33, 34) conducted “after the fact”represented beneficial applications of the McLEAN data base. Generally,the data reduction and analysis of the McLEAN data did not appear to havethe vigor that is characterized by the data acquisition (see Table B-1) .The demand for tbe McLEAN data has been minimal to date. The lack ofdsmand should not reflect the usefulness of full-scale McLSAN data. Thedata obtained from the McLEAN represents one of the most extensive full-scale instrumentation projects conducted to date and should be utilizedas a source of data as determined applicable by a would-be researcher.The SSC should be alert to this data base for future applications. Thedocumentation of the McLEAN full-scale data base has been included inseveral references. Appendix B provides a summary that describes theMcLRAN data base for future data users. Limited documentation per-taining to the rationale and engineering involved with the instrumenta-tion, selection, placement, data acquisition and reduction requirementsrestricts full evaluation of the instrumentation system with regard tothe original objectives and goals for the program.
The research plan outlined by Siekierka in SSC-257 (5) did not includeplans to develop methods for containerahip design. Many of the instru-mentation locations on the McLEAN were intended to provide design in-formation to Sea-Land directly. The documentation of the sL-7 researchprogram (l-34) indicates the problem areas pertaining to containershipdesign, in certain instances, and are included in the evaluation tables(4-1). However, the resolution nf the design problems and development ofdesign methods has not been documented in the open literature. Elbatouti(30) did present several valuable recommendations for the design of con-tainershipa obtained from the DAISY finite-element analysis, and theseare included in the summary of Reference 30 in Appendix A.
Model Testing Techniques
The hydrodynamic and static structural model tests that were conductedas part of the SL-7 research progrsm provided the major source of datafor the validation of analytical prediction techniques. The modeltests provided response data from a quantified loading source; thus,response comparisons can be made on a standard basis. There are indica-tions from the researchers who made the comparisons between model testsand analytical predictions that there is ronm for improvement in themodel testing procedures for both the hydrodynamic and static structuralmodel tests. These improvements are indicated in the summary of analy-tical techniques.
Analytical Prediction Techniques
Generally the development and validation of analytical prediction tech-niques has been one of the most beneficial products of the SL-7 researchprogram. Although the validation has been based primarily on comparisonwith model testing data, both SCORES and DAISY represent structural analy-aisThehas
tools that were not validated prior to the SL-7 research program.complete validation of SCORES and DAISY against full-scale SL-7 data ‘been limited to date and over-shadowed by the reliability of the wave
55
environment measurement from the McLEAN. The comparisons between analy-tical predictions and McLEAN data represented the primary goal for theMcLEAN data according to SSC-257 (5). The full realization of this goalwith regard to McLEAN data does not appear to be obtainable from existingdata, in view of the conclusions presented by Dalzell in Reference 23.
The procedures used by ABS to obtain input information to the DAISYfinite-element computer program from a modified version of the SCORESship motion and loads computer program represent a major first step incombining the two procedures. The finite-element computer programsshould provide an excellent method for structural analysis from wave-induced loadings; however, the versions of SCORES that are available to
the general public do not produce the information needed as input to thefinite-element programs. Although the combination of hydrodynamic andfinite-element computer programs are presently extremely involved , re-finement and simplication of the techniques will eventually be extrem-ely valuable tools to the ship structural analyst.
4.2.4 Load Criteria, Analysis and Development
ABS (24) -determined that their hull girder load criteria for the SL-7 wasadequate,based cm their comparisons between the DAISY finite-element com-puter program and full-scale data. However, the existence of fatiguecracks at the forward hatch on the sL-7 indicates that the hull girder de-sign had deficiencies from a ship operator’s standpoint. The load cri-teria”studies (33, 34, 35) were not included in the original SL-7 researchplan, but were additional studies that used the McLEAN data base for appro-priate applications. Generally the studies evaluated in Section 4.1 haveshown that the statistical techniques necessary to develop a complete pic-ture of ship structural response throughout the ship’s lifetime are quitecomplex. The studies indicate that the number of variables involved inquantifying the total ship structural response are numerous and difficultto separate, for example, the response from various types of bending mom-ents frcm ship loading, the ship’s wave train, thermal effects, and thevarious loads induced by wave encounters.
To date, the full-scale SL-7 data have been used to aid in the develop-ment of a rational load and design criteria. However, as these studiesindicate, considerable effort is still required to develop design cri-teria or design methods using statistical techniques. Additional effortis required to define statistically all the types of hull structural load-ings (various wave-induced loads, mean stresses, thermal stresses, etc.)for various ship types. The probabilistic techniques have been successf-ul in evaluating existing load criteria but as a pure design method isformidable in its total scope in the view of today’s average structuralanalyst.
The methods for the development of a rational hull girder load criterionusing a statistical combination of loads from all the various sources wasoriginally presented in SSC-240 (35). The method was reexamined in SSC-287 (33); however, the evaluation was inconclusive and validation of thestatistical technique as a design method remains incomplete.
56
4.3 OVERALL EVALUATION OF THE SL-7 RESEARCH PROGRAM
The goals and objectives of the SL-7 research program have met with vary-ing degrees of success.
The load criteria applied in the design of the SL-7 primary hull struc-
ture has been found to be adequate by the American Bureau of Shipping.
The occurrence of fatigue cracks at the forward hatch corners has been
reported (10) . (In fact, in the absence of a detailed damage survey it
is likely that such cracks may have occurred at other hatch corners. ) Thepresence of such cracks is known to have been a concern of the operators,Sea-Land Service, Inc. The inference is that from an operations point ofview the criteria used for the design of the SL-7 structure requires re-examination. In a negative sense, the fact that the SL-7 program has il-”lustrated this deficiency may be considered a success. The program hasprovided valuable full-scale data, some of which has already been analyzedby ABS for the development of structural detail design methodologies whichmay be applied to the design of high-stress concentration areas, such asthose encountered on the SL-7 class ships (43).
‘he validation of hydrodynamic ship load and response prediction techni-ques has a~so met with varied success. Three types of model tests havebeen used to produce data for validation of analytical techniques. Theseinclude hydrodynamic structural, static structural and open-water modeltests. The information produced by the model tests has been valuable invalidation of the SCORES (hydrodynamic load and response prediction) ,DAISY (finite-element computer program) , and USCG time domain (hydrodynamicload and response prediction for capsizing in following seas) computer pro-grams with additional testing indicated in all instances.
ABShas conducted comparisons of their DAISY finite-element program andthe full-scale data obtained from the McLEAN. ‘lhiscomparisons involvedthe development of hull pressure information (from a version of the SCORESprogram and special post-processor) and input into the finite-element pro-gram. However, the wave environmental data obtained from the McLEAN which
was used as input for the analytical simulations has been found to be sus-pect. Although the analytical techniques have been validated against themodel tests, comparisons against full-scale sL-7 data have not been exten-sive or conclusive enough to consider the techniques validated as part ofthe present SL-7 research program. The unreliability of the wave dataseverely limits the further application of full-scale McLEAN data for thevalidation of analytical techniques.
There will be a continuing demand for full-scale data that will be usedfor validation of analytical techniques. Several SSC projects have beendeveloped to obtain additional full-scale data for a wide range of appli-
cations. Many of these projects are in the planning stages and many ofthe projects are still speculative. The projects that will requireadditional full-scale data for validation efforts are second-generationship motion and response simulations. The USCG experience described inthis report indicates a general trend toward time domain simulations forrare or extreme events by the community in general. SSC is currently
57
sponsoring the development of an advanced ship motion computer simulationprogram (SSC Project SR-1277) which will include nonlinear effects. Sev-
eraI efforts are also underway to develop specialized programs to predictloads and responses of the ship to bottnm slamming and deck wetness. Atsome point in time these analytical techniques will require additionalfull-scale data which will provide the criteria against which all tech-niques for predicting structural response must be judged. Hopefully,
these programs will be able to use the SL-7 experience as a modeling base.The future programs that will require full-scale data will ideally re-quire some qualitative measure of the wave environment.
The STEWART J. CORT program (44) is currently investigating the effectsof springing in Great Lakes ore carriers and has benefited from the SL-7program in considering the evaluation of the wave-meter systems. TheSTEWART J. CORT research program is also following a specialized trendthat will probably be indicative of future research programs. It was
organized specifically to obtain Response Amplitude Operators (RAOS)for springing response analysis. This trend will very likely continuefor validation of specialized analytical techniques for predicting slam-
ming loads and loads from green water on deck, etc. for the wide rangeof future needs. Future programs will require planning efforts forspecialized needs relative to instrumentation types, data acquisitiontechniques, and data reduction required. The SL-7 research program hasshown that the data-acquisition requirements for obtaining a statistical
sample of strain data are not necessarily compatible with the amount ofquality data actually needed for validation of analytical predictiontechniques, and that this potential conflict should , in the future, beresolved at the planning level.
Several overall observations, apparent in reviewing the SL-7 researchprogram that pertain to instrumenting ships in general, are presentedhere. The costs that the owners of the vessel must absorb for calibra-tion periods, delays, etc. , are such that the goals of any program maybe compromised. Accordingly:
1. Instrumentation should be installed and calibrated during con-struction, dry-dock or lay up.
2. Proper planning of the calibration experiment and voyage data-taking phases is essential.
A body such as SSC is a good coordination group; however, the Prime con-tractor project should not necessarily be an organization primarily in-terested in instrumentation. Ideally,a naval architecture firm shouldbe amployed to coordinate the interests of SSC, ABS, ship designers,builders, researchers and owners. Initially, ASS coordinated much ofthe SL-7 Research Program and,therefore,derived mOst Of the benefits.
One central head or leader, that ideally is technically equipped and hasa vested interest in the final product, is needed to provide consistentoverall direction.
58
F
5.0 RECOMMENDATIONS
The,following recommendations are derived from the summary and conclusionspresented in the previous sections, and do not include the numerous otherrecommendations presented in the SL-7 reports.
1.
2.
3.
4.
The research plan outlined in SSC-257 by Siekierka (5) was not fullyimplemented. Further implementation is not recommended due to thelimitations (as determined by Dalzell in Reference 23) of wave en-vironmental data from the McLEAN instrumentation project.
The deficiencies of the wave environmental data limit further use of
the McLEAN full-scale data for validation of analytical procedures
for predicting wave-induced loads. Therefore, no further validation
efforts in this area are recommended.
The SL-7 Research Program data base, including the full-scale McLEANdata base described in Appendix B, represents one of the most exten-sive data bases obtained to date. It is recommended that maintenanceof this data base by the SSC be co,]tinued and that the SSC utilizethe data base as the specific needs and applications arise.
It is not recommended that a detailed research plan for further useof the McLEAN data be developed; however, it is recommended thatthe SSC advertize and direct ship researchers, designers and buildersto the SL-7 data base as the demand for full-scale data, model testdata and analytical simulation results arise. The SL-7 data base isextremely useful but it should be left to the individual researcherto decide on the applicability of the data base to their specificneeds. For example, the McLEAN data base may lend some insight intothe ranges of strain-rate studies concerned with structural strainsand those induced from drydocking, or fatigue cracking studies. Itwould be the responsibility of the SSC to be alert to the existenceof the present McLEAN full-scale instrumentation data base and ad-vertize its availability. All of the possible uses of the McLEAN dataare too numerous to list here. Several types of analyses of McLEANdata are presented in Appendix B. Examples of further analysis ofMcLEAN data include:
● The highest hull girder stresses ever measured on the shipsinstrumented by TES occurred on the forward hatch of the McLEAN(79,000 psi P-T) . The circumstances surrounding their occur-rence would be extremely interesting.
● The data recorded at the forward hatch corner above radialcracks were observed and could possibly provide a data base forfuture fatigue analysis programs. However, these data are still
in analog form, as recorded, and have not been analyzed in a use-able form for fatigue analysis.
● The correlation of seaway stresses and hatch opening deflectionsoriginated by Sea-Land has not been completed and published in
59
the open literature. This information was intended to aidSea-Land in the design of transverse box girders and hatchcover seals (see discussion in Table 4-1) .
● Development of long-term statistical distributions of wave-
induced stresses obtained from amidahip vertical bending and
hatch corners. The long-term statistical distributions would
be developed on the same basis (i.e. Beaufort Number, etc. )
and may provide insight into the long-term effects of stress
concentrations on existing hull girder load criteria. This
could also be conducted for various headings to isolate tor-
sional effects.
5. Generally the documentation on the individual sL-7 research projectshas been exceptional in describing the work reported. However, adetailed documentation of the planning effort involved in the full-scale element of the SL-7 research program would be beneficial tofuture research programs of a similar nature. References 1 and 5contain a brief summary of the instrumentation purpose; however,no published document contains a detailed description of the plan-ning efforts involved with the full-scale instrumentation elementof the sL-7 research program. Information on the engineering effortand rationale involved in instrumentation selection, instrumentationplacement, data acquisition and the required data reduction is verylimited in published SSC documents. This information, if availableto the research community, would be of great benefit for future full-scale instrumentation programs of a similar nature. For example, theinformation could aid in the determination of strain-gauge instru-mentation placement without going through the deliberations thatmust have taken place in deciding the placement of strain gauges on
the McLEAN. It is recommended that the SSC collect and publish in-formation relating to the engineering effort and planning of the sL-7program, if available. In fact, the lesson to be learned from thisprogram is that all future similar programs should be preceded by
a published full-scale instrumentation test plan.
6. The results of the SL-7 research program indicate strongly thatadditional development of wave measurement systems is needed. Animproved sL-7 wave-measurement system has recently been utilized
as part of the STEWART J. CORT (43) research program; however,experience at this time has been limited to lower sea states. Fur-ther development of wave-measurement syst&.s may be required forlarge seaways and at higher speed ranges before validation ofexisting or new analytical techniques can be completed. It is re-commended that development and verif ication of such wave-measurementsystems be continued actively in anticipation of future full-scaletests.
7. It is recommended that McLEAN cargo, ballast and consumable loadingconditions that existed upon departure for the various voyages wheredata were recorded be obtained from Sea-Land Services, Inc. andincorporated as part of the McLEAN data base.
60
.
6.0
7.0
8. It is recommended that future full-scale instrumentation programsprovide a means for recording the initial mean stress upon depar-ture for each voyage. This information is necessary for futureload criteria analysis and development, in particular still-water
bending moment informat ion.
9. The only scratch-gauge data recorded on 8 ships of the SL-7 classthat have supplementary project logbook data are those correspondingto the first three data seasons on the McLEAN. It is recommendedthat an investigation be conducted as to the availability of ships’logbook information to supplement the scratch-gauge data recordedon other ships. This information would be obtained from Sea-Landand maintained with the scratch-gauge data at Teledyne EngineeringServices in Waltham, Massachusetts.
10. It is recommended that a survey be conducted to provide insight in-to the extent of damage sustained by the sL-7s during their serviceas commercial containerships. The damage survey would include thedocumentation of the circumstances surrounding the voyages whendamage occurred.
EPILOGUE , THE SL-7 CONTAINER SHIP
At the present time (1981), the SL-7 containership is being phased out ofcommercial service. The cost of oil has risen from $2 a barrel to $35 abarrel since the time these ships were designed, and this high-speed capa-bility is no longer economical. The trends toward high speed in commercialcargo ships which developed in the late 60s and 70s are beginning to phaseout. The United States Navy is considering purchase of the sL-7 con-tainerships for military logistic support applications, although when theclass was designed, such an application was not considered in the struc-
tural design. Often ships will shift to other services, carry differentcargo, or travel different routes than were initially considered whenthey were designed, and such may be the case for the SL-7 class. Underthese conditions, the load criteria used in the original design of theSL-7 containerships may no longer be applicable.
Although the demand for high-speed containerships has diminished inrecent years, the majority of the conclusions and recommendationsprogram are applicable to open-decked ships as well as other ship
ACKNOWLEDQ4ENT S
The authors would like to acknowledge the work of the researchers
of thistypes.
invOl-ved in the sL-7 program. The summary, conclusions and recommendationsof this report have been influenced to a large degree by the work ofothers involved in the program and are offered recognizing the benefitsof hindsight.
61
8.0 REFERENCES
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16,
17,
18.
Fain, R.A. , “Design and Installation of a Ship Response InstrumentationSystem Aboard the SL-7 Class Containershp S.S. SEA-LAND McLEAN, ”1974, sL-7-1 , SSC-238, AD 780090.Dalzell, J.F. and Chiocco, J.J. , ‘rWaveLoads in a Model of the SL-7Containership Running at Oblique Headings in Regular Waves”, 1974,
SL-7-2, SSC-239. AD 780065.Elbatouti, A.M. , Liu, D. and.Jan, H.Y., “Structural Analysis of SL-7Containership Under Combined Loading of Vertical, Lateral and TorsionalMoments Using Finite Element Techniques, “ 1974, SL-7-3, SSC-243.AD AO02620 .Kaplan, P. , Sargent, T.P. and Cilmi, J., “Theoretical Estimates OfWave Loads on the SL-7 Containership in Regular and Irregular Seas,”1974, SL-7-4, SSC-246. AD AO04554.Siekierka, W.J. , Johnson, R.A. and CDR Loosmore, C.S. , USCG, “SL-7Instrumentation Program Background and Research Plan,” 1976, SL-7-5,SSC-257 . AD A021337.Rodd, J.L., “Verification of the Rigid Vinyl Modeling Techniques:The SL-7 Structure. ” 1976. sL-7-6, SSC-259. AD A025717.Boentgen, R.R. and Wheaton, J.W. , “Static Structural Calibrationof Ship Response Instrumentation System Aboard the SRA-LAND McLEAN, “1976, SL-7-7, SSC-263. AD A031527.Boentgen, R.R. , Fain, R.A. and Wheaton, J.W. , “First SeasOn Resultsfrom Ship Response Instrumentation Aboard the SL-7 Class ContainershipS.S. SEA-LAND McLEAN in North Atlantic Service, ” 1976, SL-7-8, SSC-264.AD A039752.Wheaton, J.W. and Boentgen, R.R. , “Second Season Results from ShipResponse Instrumentation Aboard the sL-7 Class Containership S.S.SEA-LAND McLEAN in North Atlantic Service, ” 1976, SL-7-9. AD A034162.
Boentgen, R.R. , “Third Season Results from Ship Response InstrumentationAboard the SL-7 Class Containership S.S. SEA-LAND McLEAN in NorthAtlantic Service, ” 1976, SL-7-1O. AU A034175 .Webster, W.C. and Payer, H.G. , “Structural Tests of SL-7 Ship Model, ”1977, SL-7-11, SSC-269. AD A047117.Kaplan, P., Sargent, T.P. and Silbert, M. , “A Correlation Study ofSL-7 Containership Loada and Motions - Model Tests and ComputerSimulation, ” 1977, SL-7-12, SSC-271. AU A049349.Chen, D. and Hammond, D. , “A Report on Shipboard Wavehe ight RadarSystem, ” 1978, SL-7-13. AD A053379.Dalzell, J.F. , “Original Radar and Standard Tucker Wavemeter SL-7Containership Data Reduction and Correlation Sample, ” 1978, SL-7-14,SSC-277. AD A062394 .Dalzell, J.F. , “Wavemeter Data Reduction Method and Initial Data forthe SL-7 Containership, ” 1978, SL-7-15, SSC-278. AD A062391.Dalzell, J.F. , “Radar and Tucker Wavemeter Data from S.S. SEA-LANDMcLBAN - Voyage 32,” 1978, SL-7-16. AD A057154.Dalzell, J.F. , “Radar and Tucker Wavemeter Data from S.S. SEA-LANDMcLEAN - Voyage 33,” 1978, SL-7-17. AD A057155.Dalzell, J.F. , “Radar and Tucker Wavemeter Data from S.S. SEA-LANDMcLBAN - Voyage 34;“ 1978, sL-7-18. AD A057156.
62
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.35.
36.
37.
38.
39.
Dalzell,McLEAN -Dalzell,
J.F., “Radar and Tucker Wavemeter Data from S.S. SEA-LANDVoyages 35 and 36E,” 1978, SL-7-19. AD A057157.
J.F., “Modified Radar and Standard Tucker Wavemeter SL-7Containership Data, ” 1978, sL-7-20, SSC-279. AD A062393.Dalzell, J.F. , “Radar and Tucker Wavemeter Data from S.S. SEA-LANDMcLFAN - Voyage 60. 1978. SL-7-21. AD A057004 .Dalzell, J.F. , “Radar and Tucker Wavemeter Data from S.S. SEA-LANDMcLEAN - Voyage 61.” 1978. sL-7-22 . AD A05 7005.Dalzell, J.F. , “Results and Evaluation of the SL-7 ContainerahipRadar and Tucker Wavemeter Data, ” 1978, SL-7-23, SSC-280. AD A062392.Jan, H.Y., Chang, K.T. and Wojnarowski, M.E. , “Comparison of StressesCalculated Using the DAISY System to Those Measured on the SL-7Containership Program. ” 1979. SL-7-24, SSC-282.Fain, R.A. and Booth, E.T. , “Results of the First Five ‘Data Years’of Extreme Stress Scratch Gauge Data Collected Aboard SEA-LAND’ssL-7’s, ” 1979, SL-7-25 , sSC-286.Oakley, Jr. , O.H. , Paulling, J.R. and Wood, P.D. , “Ship Motions andCapsizing in Astern Seas,” 10th Symposium on Naval Hydrodynamics,Office of Naval Research, June 1974.Haddara, M.R. , Kastner, S., Magel, L.F. , Paulling, J.R., Perez y Perez,L ., Wood, P.D., “Capsizing Experiments with a Model of a Fast CargoLiner in San Francisco Bay, ” prepared for the U.S. Coast Guard underContract No. DOT-CG-84, 549-A, January 1972.Perez y Perez, L. , “A Time Domain Solution to the Motions of a SteeredShip in Waves, ” Report No. CG-D019-73, prepared under Contract No.DOT-CG-84, 549-A, November 1972.Bovet , D.M. , “Development of a Time Domain Simulation for Ship Capaizingin Following Seas” Report No. cG-D-28-74, October 1973.
Elbatouto, A.M.T. , Jan, H-Y, Stiansen, S.G., “Structural Analysisof a Container sip Steel Model and Comparison with the Test Result s,”SNAMS Transactions, November 1976.Oliver, J.C. , “Evaluation of SL-7 Scratch Gauge Data, ” Giannotti &Associates, Inc., Draft Final Report to SSC, September 1980.Giannotti, J.G. , ,,FatigueLoad spectra Development for Ship Hulls, ”
for Teledyne Engineering Services, Inc., September 1980.Dalzell, J.F. , Maniar, N.M, Hsu, M.W., “Examination of Service andStress Data of Three Ships for Development of Hull Girder Load Criteria, ”SSC-287 , 1979.Zubaly, R. , “Evaluation of Full-Scale Wave Loads, ” SNAME, panel HS-1.Lewis, E.V., Hoffman, D., MacLean, W.M. , Van Hooff, R. , Zubaly, R.B.,“Load Criteria for Ship Structural Design, ” SSC-240, 1973. AD 767389.
Boylston, J.W., deKoff, D.J. , Muntjewerf, J.S., “SL-7 Containerships:Design, Construction and Operational Experience, ” SNAME, Trans. 1974.Grim, Q. and Schenzle, P. , ItThepredictiOm of Torsional Moment, Hori-
zontal Bending Moment and Horizontal Shear Force on a Ship in Waves, ”Proceedings, IMAs69, Section 3.de Wilde, G. , “Structural Problems in Ships with Large Hatch Openings, ”International Shipbuilding Progress, Vol. 14 (1967), No. 149 (Jan.)and No. 150 (Feb.), pp. 7-33, 73-83.Chazal, E.A., LCDR, Goldberg, J.E. , Nachtsheim, J.J. , Rumke, R.W. ,Stavovy, A.B., “Third Decade of Research Under the Ship StructureCommittee, ” SSC-252, 1976, AD A021290.
63
40.
41.
42.
43.
44.
Fain, R.A., Cragin, J.Q. and Schofield, B.H. , “Ship Response Resultsfrom the First Operational Season Aboard the Container Vessel, S.S.BOSTON ,“ Ship Structure Committee, Report No. SSC-212, 1970.Johnson, A.E. , Flaherty, J.A., Walters, I.J., “A Method for Digitizing,Preparing and Using Library Tapes of Ship Stress and Environment Data, “SSC-236, 1973. AD 767388.Johnson, A.R. , Flaherty, J.A. , Walters, I.J., “Computer Programa forthe Digitizing and Using of Library Tapes of Ship Stress and EnvironmentData, ” SSC-237, 1973. AD 768863.Stainaen, S.G., Jan, H.Y., and Liu, D., “Dynamic Stress Correlationfor the sL-7 Containership, ” SNAMS Trans. 1979.Hammond, D. , ,,Great Lakes Wane Height Radar System, ” USCG RePOrt NO.
CG-D-6-80, 1977. AD A083647.
64
APPENDIX A
SUMMARIES OF REFERENCES 1-34
TITLE/SSC REPORT NO. (Ref. 1)
Design and Installation of a Ship Responsethe SL-7 Class Containership S.S. SEA-LAND
DESCRIPTION
Instrumentation System AboardMcLEAN, SSC 238 (SL-7-1) .
This report describes the transducers, cabling, signal-conditioning, andrecording elements of the instrumentation system installed aboard theSL-7 containership S.S. SEA-LAND McLEAN. It includes a detailed summaryof the strain-gauge bridge circuits, locations of all transducers, and adescription of the various operating modes and options available forrecording data from more than 100 strain gauges, accelerometers and motionsensors. This document contains a detailed description of the instrumenta-
tion package installed on the S.S. SEA-LAND McLEAN. Tables II and III ofReference (1) provide a brief summary of the rationale involved in the
instrumentation selection and purpose.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMMENDATIONS
None presented in this report.
A-1
TITLE/SSC REPORT NO. (Ref. 2)
Wave Loads in a Model of the SL–7 containership Running at Oblique Headings
in Regular Waves SSC-239 (sL–7-2)
DESCRIPTION
This report describes the l/140-scale segmented model tests of the SL-7
containership where the measurements included vertical, lateral and tor-sional wave bending moments, and vertical and lateral shear forces at twomodel sections. The model had balances between segments that were instru-mented with strain gauges to infer torsional, lateral and vertical bendingmoments from strain measurements. The model response and motions weremeasured along with the waves or loading function. A set of 4-bladed pro-pellers driven by an electric motor and rudder activated automaticallywere also included in the model design.
The two model loading conditions, estimated while the ships were underconstruction as being typical ship loadings, consisted of one full loadand one ballast configuration.
The testing program contained four parts:
(1)
(2)
(3)
(4)
Smooth-water runs to measure moments and shears induced by the shipswave train.
Smooth-water tests to determine the effects of the ship’s roll res-ponse at zero speed and one forward speed.
Smooth-water runs to generate an approximate response to ruddermotions.
Regular wave runs at seven headings, two ship speeds, and various wavefrequencies and heights.
The model was self-propelled through a ship speed range of 24 to 32 knotsat seven headings in regular waves with lengths between .25 and 2.0 timesthe ship’s length between perpendiculars. The results are presented incharts of load or motion amplitude with ship heading speed and loading con-ditions as parameters.
AUTHOR’ S FINDINGS, CONCLUSIONS AND RECOMNENDATIONS
The Primary obiective of this investigation was to obtain three com-. . .ponents of wave bending moment and two components of wave shear force attwo sections of a high-speed containership. This was accomplished for thesignificant ship-wave headings. In addition, coordinated data were obtainedof the model motions.
In advance of results of correlations of the present data with theory, nopositive
.-recommendations were made as to the necessity of further testing.
A-2
.
TITLE/SSC REPORT NO. (Ref. 3)
Structural Analysis of SL-7 Containership Under Combined Loading of Vertical,Lateral and.Torsional Moments Using Finite-Element Techniques, SSC-243(SL-7-3)
DESCRIPTION
l%is document describes the analysis of the SL-7 container vessel hull struc-ture using the DAISY finite-element computer program. The ship, loaded with
containers and placed in oblique quasi-static regular waves, is subject tocombined vertical, lateral and torsional loads. Stress distributions parti-
cularly in the deck region are presented and investigated from the analysisusing the reduced-element substructure feature in the program. Fine-mesh
analyses are also presented at different locations of the ship. The computed
stresses are discussed in connection with the placement of strain-gaugeinatrumentation on the SEA-LAND McLEAN.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMNENDATIONS
The author presented ‘several conclusions pertaining to the structural responseof an open-decked containership. These observations include:
(1) A relationship between hatch distortion and the transverse box stressdistribution in this area suggested the linearity of the stress pattern.
(2) The Navier Beam Hypothesis as applied to the open-deck box girder
appeared to be adequate in predicting the primary response of the con-tainership under pure vertical bending moments.
The interpretations of the stress results at the proposed locations of somestrain gauges on the SEA-LAND McLEAN are made. Early output of the finite-element results had helped in the determination of the final location ofsome gauges.
A-3
TITLE/SSC REPORT NO. (Ref. 4)
Theoretical Estimates of Wave Loads on the SL-7 Containership in Regular
and Irregular Seas, SSC-246 (SL-7-4)
DESCRIPTION
This report describes the application of the SCORES computer program forpredicting ship structural response of the SL-7 containership in waves .Comparison is made between the computer and model tests of the SL-7(reported in sSC 239 SL-7-2) in regular waves in predicting vertical,lateral and torsional moments, and vertical and lateral shears at two sec-tions and heave, pitch and roll. Regions where the theory and model ex-periment do not agree have been pointed out and some means of correction orextension of the theory is discussed.
Additional computations were conducted for the sL-7 containership at num-bers typical to operating conditions. These results are presented in theform of both frequency responses for regular waves as well as rms forirregular seas.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOf@fENDATIONS
According to the author, the theory provided an adequate representation ofship response within the limitations of the strip theory. The lack ofagreement between theory and experiment was evident for:
(1) The influence that higher forward speed presented (Froude number effect)
(2) Following seas, where theory is considered to be tentative due to lowencounter frequencies.
(3) Lateral plane wave loads that are highly dependent upon adequate re-presentation of ship roll response with nonlinear roll damping whichis not represented in a linear lship motions program.
It was also concluded that the strip theory represented the state of the artin ship motions and loads computations and was consistent with all otheravailable ship motion analyses applicable to wave responses.
A-4
TITLE/SSC REPORT NO. (Ref. 5)
SL-7 Instrumentation Program Background
DESCRIPTION
This report presents an overview of theIt presents the experimental background
and Research Plan, SSC-257 (SL-7-5)
sL-7 research program up to 1976,upon which the program was based,
the major features and expected outputs of the program, and some pre-liminary conclusions drawn from the research results obtained from theSL-7 research program up to the time the report was written. A researchplan is also outlined for the possible data correlations and their con-sequences.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
The author recommended a research plan based on the projects that hadalready been conducted as part of the initial research plan (projectspresented in SL-7 documents 1 through 4) , and additional follow on studiesto be conducted as part of the SL-7 Research Program.
A-5
TITLE/SSC REPORT NO. (Ref. 6)
Verification of the Rigid Vinyl Modeling Technique: The SL-7 Structure,SSC-259 (sL-7-6)
DESCRIPTION
This report describes the applications of the rigid vinyl structuralmodeling technique to the hull structure of the SL-7 containership, anda comparison of the model with its steel counterpart (described inSL-7-11) under equivalent load conditions.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMMSNDATIONS
The authors concluded that the use of rigid vinyl as the modeling materialreduced construction efforts, improved the representation of complexstructural shapes and details and offered reduction of experimentalefforts due to ease of handling and convenient load magnitudes. Analysisof torsional stresses on both the steel and vinyl models revealed thatareas of high-stress concentration can be misrepresented by strain gaugeresults simply because of the range of stresses present in a small area.Based on the results obtained from the structural model tests, it was
concluded that essentially the same information was retrieved from theexperimental programs of the steel model and the rigid vinyl model.
A-6
TITLE/SSC REPORT NO. (Ref. 7)
Static Structural Calibration of Ship Response Instrumentation SystemAboard the SEA-LAND McLEAN, SSC-263 (SL-7-7)
DESCRIPTION
This document reports the results of the dock side calibration of thestrain-gauge portion of the ship response instrumentation installed onthe SEA-LAND McLEAN SL-7. The experiment was intended to facilitate
comparisons of measured stresses with calculated values resulting fromknown changes in loading, and thus verify the instrumentation system per-formance. The details of the experiment are presented in SSC-263 (7)for the loading conditions described below:
(1)
(2)
(3)
(4)
(5)
(6)
Dockside initial loading condition, with full load of containersin the hold and on deck, except beneath hatches 3, 10 and 14.
(Due to schedule constraints Condition No. 2 was deleted from thecalibration experiment. )
Deck containers on Hatches 1 through 4 and 12 through 15.
Remaining deck containers on Hatches 5 through 11 removed.
Approximately one-half of containers removed from starboard side ofHatches 1 through 7 from the port side of Hatches 8 through 15,generating a torsional moment. Hatch covers placed asymmetrically
to contribute to the torsional moment.
Completion of unloading described in Condition 5. This represents
(7)
the maximum torsional load.
Nominally empty ship except for one propeller, 47 long tons loadedinto Hatch 3 and one propeller in Hatch 4, all hatch covers on.
Calculations of vertical bending moment and torsional moment for each con-dition were provided by the ABs and the related stress changes have beencompared with the measured values. In addition to the calibration of straingauges, the diagonal displacement of a selected hatch opening was measuredin an attempt to calibrate the hatch deflection wi’thmeasured strain.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMNENDATIONS
The following general conclusions were drawn by the authors based on thedata
(1)
gathered during the calibration experiment.
Measured changes in midship vertical longitudinal bending stress wereconsistently 80 percent of the calculated changes. Because of pos-sible differences between the as-constructed and the theoretical(minimum scantling) section modulus upon which the calculations were
A-7
.
based, this correlation is reasonable and indicates furtherthat the load/response characteristic is linear and that dataacquisition and reduction techniques do not contain any sig-nificant systematic errors.
(2) Data are presented relating response to applied loads, makingpossible the development of proportionality constant.
(3) Stress levels achieved during the calibration were in most casessmall relative to maximum measured seaway stress variations, andthermal conditions were not constant over the duration of theexperiment. Therefore, extrapolations of loads by proportionalityshould be undertaken with caution.
(4) The maximum observed stress change for the calibrations loadings(10,200 psi, sensor SYA, during the torsion loading, condition 4to condition 6) occurred at the starboard aft corner of Hatch No. 9,just forward of the aft house. Other hatch corners at stationswhere hatch width changes are encountered exhibited high shearstresses near the stress relief cutouts. The hatch corners, there-fore, are probably the most highly stressed parts of the structure.
A-8
TITLE/SSC REPORT NO. (Ref. 8)
First Season Results From Ship Response Instrumentation Aboard the SL-7Class Containership S.S. SRA-LAND McLEAN in North Atlantic Service,SSC-264 (SL-7-8)
DESCRIPTION
This report contains selected examples of data, withcussions, collected during the first season on board
evaluation and dis-the S.S. SEA-LAND
McLEAN . Data collection began with west bound Voyage 1 on October 8,1972 and terminated with the east bound passage of Voyage 12 on April 5,1973. A total of 80 data tapes were recorded containing in excess of50,000 separate data recording intervals from more than 100 transducers.
Discussions include a brief description of the types of data collected,data presentation, selected comparisons of stresses with sea state andexamples of time histories of selected response data from all transducersduring selected portions of a rough voyage.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
Several qualitative observations are presented by the authors based onthe analysis of selected types of data for the first season of operation;however, this was not a detailed data analysis report and no conclusionsand recommendations were offered.
A-9
TITLE/SSC REPORT NO. (Ref. 9)
Ship Response Instrumentation Aboard the sL–7 Containership S. S. SEA-LAND
McLEAN, Results from the Second Operational Season in North Atlantic
Service.
(This report is not a SSC published document and is available from
National Technical Information Service) sL-7-9.
DESCRIPTION——
This report contains selected examples of data, with evaluation anddiscussions, collected during the second season on board the S.S. SEA-LAND McLEAN . Data collection began with East bound voyage 25 on September 22,1973. With the exception of Voyage 27 Westbound, the ship was manned untilMarch 31, 1974. The total number of individual recording intervals ofdata was 60,941. On October 29, 1973 the SEA-LAND McLEAN entered drydockafter unloading in Rotterdam. Continuous recordings were made during thetime the ship was sitting on the blocks.
Discussions include a brief description of the types of data collected,
data presentation, selected comparisons of stresses with sea state, and
selected examples of time histories of response data.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMMENDATIONS
This report did not contain detailed data analysis and no conclusionsor recommendations were offered.
The highlight of the report is the presentation of selected heavy weatherdata for the second season which included a unique slam which resultedin a total (including whipping) estimated midship bending stress excursiorat 53,600 PSI.
A-10
TITLE/SSC REPORT NO. (Ref. 10)
Ship Response Instrumental ion Aboard the sL-7 Containership S.S. SEA-LANDMcLEAN, ‘Results from the Third Operational Season in North AtlanticService(This report is not a SSC published document and is available from theNational Technical Information Service
DESCRIPTION
This report contains selected examples
(SL-7-1O) ).
of data, with evaluation and dis-cussions, collected during the third season on board the S.S. SEA-LANDMcLEAN . Data collection began with North Atlantic Voyages 59-61 duringthe period 17 January 1975 to 17 March 1975.
A significant amount of new strain-gauge instrumentation was installed
for the third season data acquisition program. The location of this
gauging was based on observations of damage incurred in the first two
years of vessel operation. Specifically, radial cracks from the forward
and some aft hatch corners and green water set-dowm of forecastle andflare plating bad been experienced. In an attempt to characterize theloading in these areas, additional strain gauges were added.
Discussions include a brief description of the types of data collected,
data presentation, selected comparisons of stresses with sea state, and
selected examples of stress time histories of response data.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMMENDATIONS
This report did not contain detailed data analysis and no conclusionsor recommendations were offered. A few qualitative observations were
presented including the observation that the highest peak-to-through stressmeasured was 79,000 psi on the forward hatch corner circumferential gauge(FYB).
A-l]
TITLE/SSC REPORT NO. (Ref. 11)
Structural Tests of SL-7 Ship Model, SSC 269 (SL-7-11)
DESCRIPTION
This report describes a steel structural l/50th scale model test programfor the SL-7 containership, the development of the model, and testresults.
The objectives of the SL-7 structural model tests were to:
(1) Provide a more comprehensive view of the structural deflections and
stresses for various component loadings than obtained from real shipdata. (Prior to this study, no full-scale programs measured shiploading. )
(2) Provide sufficient information with which to check and validate thefinite-element calculations for typical ship structures.
(3) Investigate the effect of warping restraint afforded by closed sec-tions of the hull on torsional response.
The investigation included the development of the model size, materialand construction. The scaling laws were examined and model particulars
selected were based on this analysis.
The model was constructed of light gauge steel. As a result of severalpractical considerations, it was found necessary to increase the thicknessof the structural components to reasonable commercial sizes to reduce thenumber of structural parts, thus simplifying the three-dimensional formof the ship hull. Several of the girders and stiffeners were takentogether and were represented by one component with an equivalent crosssection, while areas of the small plate stiffeners were included in thearea of the plating. The structural model was loaded by means of calibrated
weights, through a PU1lY and lever system, applied at a finite number oftransverse bulkheads to provide a good distribution of load through loadingbars. Discrete vertical, longitudinal and twisting loads were introducedto the model through the loading bars.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECO~ENDATION S
The investigators concluded that:
(1) It was possible to develop a satisfactory, relatively small-scale model,but it was necessary to have the plating thickness slightly largerthan the scale ratio would indicate.
(2) Because of construction procedures and availability of standard steelplate sizes, it was not possible to include all of the structural
A-12
.
(3)
(4)
(5)
(6)
complexity of the full-scale ship in the model. The secondarystructure was omitted and much of the primary structure wassimplified.
The results indicated that the pure vertical bending results werecomparable with elementary beam theory.
The tests of horizontal bending showed that elementary beam theoryproduced comparable results; however, the strains were quite Small
and not as well defined as for vertical bending.
The response of the ship to pure torsion indicated that bow, sternand machinery box structure were effective in restraining the ship’shull girder warping.
The vertical shear pattern appeared to have the correct shape andmet the proper boundary conditions at the keel and deck edges. Itwas concluded by the researchers that the model welds were notcapable of representing stress concentrations.
A-13
L_
TITLE/SSC REPORT NO. (Ref. 12)
A Correlation Study of sL-7 Containership Loads and Motions Model Testsand Computer Simulations, SSC 271 (sL-7-12)
DESCRIPTION
A correlation study was carried out (for the sL-7 containership) by
comparing results for structural loads and motions in waves obtained
from model tests with computer calculations. The different aspects that
could affect computer predictions “ere examined via further computations
and analyses in order to determine their influence on the output data.
Similarly, an examination of the possible effects that influence the modeltest data was made. The main objective of this study was todetermine the capabilities of both test methods for prediction purposes.
Comparisons were made between theoretical predictions and resultsfor other related ship models for which test data are available. Consis-tency of various results obtained is used as a basis for assessing thedegree of validity of any particular method, as well as determining theexact difference in results due to various mechanisms that influenceboth the theory and experiments . Improvements in the theoretical modelleading to an extended SCORES theory are described, together with com-
parisons of a range of available data for the SL-7 and other ships. Theseareas of extended theory include:
(1) Incorporation of the Frank close-fit techniques for development of
hydrodynamic coefficients instead of the Lewis form method originally
employed
(2) Incorporation of speed-dependent terms in the equations of motion
(3) Influence of rudder deflection in ship structure response
(4) Incorporation of the effects of nonlinear roll on ship response
The influence of each of these extensions to the sCORES theory are presentedin the report.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
The authors concluded that the different elements considered to modifythe basic theory had negligible effects except for the addition of certainspeed-dependent terms in the equations of motion that result in theextended sCORES theory. The authors also concluded that this theoreticalmodel has shown good correlation with model-test data for conventionalships, another large, fast containership similar to the SL-7, and alsofor the SL-7 vertical-plane responses. The extended SCORES theory canbe used over the entire range of conditions, with sufficient accuracyat low encounter frequencies, and does not require special treatment of
A-14
hydrodynamic forces just for that region in order to provide adequatevertical-plane load predictions.
It was found that the major problem for correlation of the SL-7 lateral-plane responses occurs in quartering-seas where large roll motions occur.However, the model testing procedures in these areas were also questioned.
The recommendations for further work in the area of sL-7 data correlationincluded:
(1)
(2)
(3)
Further model studies carried out in the quartering-sea range,preferably with a large model and/or special test apparatus thatwould be more suitable to “tender” ship models with directionalcontrol problems.
A more detailed determination should be made of the model roll staticand inertial properties prior to the tests to insure consistency ofthe resulting valuea.
The roll-decay tests should be made with more information on timehistories of motion presented, allowing more precise anaylsis ofdamping parameters (linear and non-linear) , as well as using morethan one method of initial roll distrubance as a means of checkingrepeatability of decay characteristic.
A-15
L.
TITLE/SSC REPORT NO. (Ref. 13)
A Report on Shipboard Waveheight Radar System. This report is not apublished SSC document and may be obtained from the National TechnicalInformation Service in Microfiche (SL-7-13)
DESCRIPTION
This report describes the microwave shipboard wave height radar sensordeveloped by the Naval Research Laboratory for measuring the ocean wavespectra and installed on the S.S. SEA-LAND McLEAN. The report presents adetailed description of the electronic instrumentation and data acquisitionused by the system. The report also presents a brief description of thecorrections needed in measuring absolute wave heights from a moving vessel.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
The objective of this report was to discuss the utilization of the micro-wave sensor on.a moving vessel for measuring the open ocean wave spectra.No significant findings, conclusions or recommendations were presented.
A-16 L.
TITLE/SSC REPORT NO. (Ref. 14)
Original Radar and Standard Tucker Wavemeter SL-7 Containership DataReduction and Correlation Sample, SSC-277 (SL-7-14)
DESCRIPTION
This report is the first in the series of 10 and involves the initial
stages of the work to analyze and correlate the wave data obtained from
the two wavemeter systems installed cm the S. S. SEA-LAND McLEAN.
Specifically, this report documents the several decisions and methods
thought necessary in conversion of the raw data from its original analog
form to digital form, the sampling and calibration of data from the
second (1973-1974) season, and a sumnary of initial results. It was
apparent frm this initial work that large amounts of information (data)is needed before an absolute wave height measurement may be obtained.
AUTHOR ‘S FINDINGS, CONCLUS IONS Am RECOMMENDATIONS
noof
conclusions or recommendations are presented in this report. A summary
findings, conclusions and recommendations appear in SSC 280 (sL-7-23) .
A-1 7
TITLE/SSC REPORT NO. (Ref. 15)
Wavemeter Data Reduction Method and Initial Data for the SL-7 Container-ship, sSC-278 (SL-7-15)
DESCRIPTION
This report is the second of a 10 document series on the verification andcorrelation of the wavemeter data obtained from the SL-7 SEA-LAND McLEAN.It describes part of the work involved to reduce data, to develop andimplement corrections as were found necessary and feasible, and to cor-
relate and evaluate the final results from the two wavemeters installed
on the S. S. SEA-LAND McLEAN. It documents some background analyses, aswell as those which were necessary to develop the needed corrections to
tbe raw digitized wavemeter data. Implementation of the results of thevarious analyses in a second data reduction stage is also discussed. The
second stage of data reduction consisted primarily of efforts to obtain a
point spectra from a moving ship and define the transformations needed to
correct the wave measurements which include ship mot ions.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMMENDAT IONS
No conclusions or recommendations are presented in this report. A summary
of findings, conclusions and recommendations appear in SSC 280,
(SL-7-23) .
A-18
TITLE/SSC REPORT NO. (Ref. 16)
Radar and Tucker Wavemeter data from SEA-LAND McLEAN Voyage 32, (SL-7-16)(This is not a SSC designated document. )
DESCRIPTION
This report is the third of a 10 document series on the verification
and correlation of the wavemeter data obtained from the SL-7 SEA-LAND
McLEAN. The report presents reduced wavemeter and amidship bendingstress data in the form of time histories and spectral plots for therecording intervals of voyage 32. The corresponding logbook data arealso presented.
AUTHOR’s FINDINGS, cONcLuSIONs AND RECOMMENDATIONs
This document is strictly a data report. No conclusions or recommenda-tions are presented in this report. A summary of findings, conclusionsand recommendations appears in SSC 280 (SL-7-23) .
A-19
TITLE/SSC REPORT NO. (Ref. 17)
Radar and Tucker Wavemeter Data from SEA-LAND McLEAN Voyage 33, (SL-7-17)(This is not a SSC designated document. )
DESCRIPTION
This report is the fourth of a 10 document series on the verificationand correlation of the wavemeter data obtained from the SL-7 SRA-LANDMcLEAN. The report presents reduced wavemeter and amidship bending stressdata in the form of time histories and spectral plots for the recordingintervals of voyage 33. The corresponding logbook data are also presented.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
This document is strictly a data report. No conclusions or recmmnenda-tions are presented in this report. A summary of findings, conclusionsand recommendations appears in SSC 280 (sL-7-23).
A-20
TITLE/SSC REPORT NO. (Ref. 18)
Radar and Tucker Wavemeter Data from SFA-LAND McLEAN Voyage 34, (SL-7-18)(This is not a SSC designated document. )
DESCRIPTION
This report is the fifth of a 10 document series on the verificationand correlation of the wavemeter data obtained from the SL-7 SEA-LANDMcLEAN . This report presents reduced wavemeter and amidship bendingstress data in the form of tfme histories and spectral plots for therecording intervals of voyage 34. The corresponding logbook data arealso presented.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
This document is strictly a data report. NO cOnclusiOns Or recO~enda-tions are presented in this report. A summary of findings, conclusionsand recommendations appears in SSC 280 (sL-7-23) .
A-21
TITLE/SSC REPORT NO. (ref. 19)
Radar and Tucker Wavemeter Data from SEA-LAND McLEAN Voyages 35 and 36E,(SL-7-19)(This is not a SSC designated document. )
DESCRIPTION
This report is the sixth of a 10 document series on the verification andcorrelation of the wavemeter data obtained from the SL-7 SEA-LAND McLEAN.This report presents reduced wavemeter and amidship bending data in theform of time histories and spectral plots for the recording intervals ofvoyages 35 and 36E. The corresponding logbook data are also presented.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMMENDATIONS
This document is strictly a data report. No conclusions or recommenda-tions are presented in this report. A summary of findings, conclusionsand recommendations appears in SSC 280 (SL-7-23) .
A-22 L.
r
TITLE/SSC REPORT NO. (Ref. 20)
Modified Radar and Standard Tucker Wavemeter SL-7 Container ship Data,
SSC 279 (sL-7-20)
DESCRIPTION
This report is the seventh of a 10 document series on the verification
and correlation of the wavemeter data obtained from the SL-7 Sfk-LANDMcLEAN . This report presents the methods used to convert raw data fromits original analog form to digital form, the sampling and calibrationof data from the third season (1974-1975) of the wave data obtained fromthe two wavemeter systems installed on the S.S. SEA-LAND McLEAN.
AUTHOR ‘s FINDINGS, CONCLUS IONS AND RECOMlfENDATIONS
No conclusions and recommendations are presented in this report. A
summary of findings, conclusions or recommendations appears in SSC 280
(SL-7-23) .
A-23
TITLE/SSC REPORT NO. (Ref. 21)
Radar and Tucker Wavemeter data from SSA-LAND McLEAN Voyage 60, (sL-7-21)(This is not a SSC designated document. )
DESCRIPTION
This report is the eighth of a 10 document series on the verificationand correlation of wavemeter data obtained from the SL-7 SRA-LAND McLEAN.This report presents reduced wavemeter and amidship bending data in theform of time histories and spectral plots for the recording intervalsof voyage 60. The corresponding logbook data are also presented.
AUTHOR’ S FINDINGS, CONCLUSIONS AND RECOMMSNDATIONS
This document is strictly a data report. No conclusions or recommenda-tions are presented in this report. A summary of findings, conclusionsand recommendations appears in SSC 280 (sL-7-23) .
A-24
TITLE/SSC REPORT NO. (Ref. 22)
Radar and Tucker Wavemeter Data from SEA-LAND McLEAN Voyage 61, (sL-7-22)(This is not a SSC designated document. )
DESCRIPTION
This report is the ninth of a 10 document series on the verificationand correlation of wavemeter data obtained from the sL-7 SEA-LAND McLEAN.This repnrt presents reduced wavemeter and amidship bending data in theform of time histories and spectral plots for the recording intervals of
voyage 61. The corresponding logbook data are also presented.
AUTHOR ‘S FINDING, CONCLUSIONS AND RECOMMENDATIONS
This document is strictly a data report. No conclusions or reccmunenda-tions are presented in this report. A summary of findings, conclusionsand recommendations appears in SSC 280 (SL-7-23) .
A-25
TITLE/SSC REPORT NO. (Ref. 23)
Results and Evaluation of the SL-7 Containership Radar and TuckerWavemeter Data, SSC 280 (sL-7-23) .
DESCRIPTION—
This report presents the findings, conclusions and recommendationsobtained from the correlation and verification of the wavemeter datafrom the SL-7 SEA-LAND McLEAN. This report is the last of a 10 docu-ment series on the analysis of the data obtained from a Tucker wavemeterand radar wavemeter. The analysis included reduction of raw data in
order to correlate and evaluate the final results from the two wavemeters.
In carrying out this work, it was necessary to at least partly reduce
several other channels of data recorded on the SL-7 SEA-LAND McLEAN, sothat, as a by–product, reduced results were obtained from midship bending
stress, roll, pitch and two components of acceleration on the ship’s
bridge. The additional data reduction was necessary primarily to obtain
an absolute wave height measurement from a moving ship. The midshipbending stress was used to generate stress RAO’S which formed a basis
for comparisons of the wave data obtained for the two wavemeter systems
and model test data.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMlfENDATIONS
TIe conclusions and recommendations presented in this report are quite
lengthy, but are very pertinent relative to the overall sL-7 research
program and future programs of similar nature. No attempt has been made
to summarize the conclusions and recommendations presented by the author
which are included here in their entirety.
A-26L
CONCLUSIONS
“The wave instrumentation included in the sL-7 program included a newsystem (the OWHS radar) and an old system (the Tucker meter) . The
basic minimum objective of the present project was to produce estimatesof encountered wave variance or nns from the data produced by each sys-tem, and most of the work necessary in the present project was in supportof this objective. Beyond this, the final objectives of the present pro-gram involved comparisons of results from the two wave measuring systemsand the resolution of differences where possible. This latter objectivehas been addressed in the present report, and is the primary subject ofthe conclusions to follow.
“ (1)
“(2)
“(3)
“(4)
“(5)
1’(6)
The evidence strongly suggests that neither ofsystems can be regarded as a standard by whichthe other may be judged.
the wave measuringthe performance of
In the present application to a large, high-speed ship, it appearsthat quite significant errors in the Tucker meter output may beattributed to the characteristics of the analog double integrationof acceleration. Improvements to this part of the system seem feas-ible within present technology. If the radar estimates happen to becloser to reality than the Tucker estimates, the existing correctionsto the Tucker meter output for the attenuation of dynamic pressurewith depth and for interference with the waves by the ship are con-siderably in error. If this is true, there appears no alternativeto full-scale calibration trials for the calibration of the system.
There appear to be a number of deficiencies in the installed OWHSradar system. Some of these produce errors of a magnitude which is
impossible to assess because some significant pieces of informationare missing. One of these deficiencies had the effect of reducing the
aPParent reliability of the radar system to quite low levels during theperiod of greatest interest (severe wave conditions) . However, it
appears that all of the problems perceived in the system may be sig-nificantly reduced by less than heroic measures.
The source of error common to both systems has to do with the pro-blems of double integration of low-frequency acceleration data. Inthe present applicat~on~ the speed of the ship andweather together tend to produce encountered waveextremely low frequency as much as half the ttie.are lost in the Tucker analog integration and nothandled by the data reduction system employed for
the prevailingcomponents ofThese componentsalways successfullythe radar data.
There is a wide, systematic difference between the rms encounteredwaves (and the wave spectra) as measured by the radar and by theTucker systems.
Estimates of significant wave height from neither system correlateparticularly well with visual estimates. Relative to visual esti-mates the radar results are too high and the Tucker meter estimatesare too low.
A-27
.
‘I(7) An indirect comparison of the wave spectra estimated by the two sys-tems was made by deriving apparent midship stress response operators,
and comparing these results with model test data for the sL-7 classship. These comparisons suggest that the radar wave estimates aretoo high and the Tucker estimates too low. Quantitatively, however,if the Tucker meter wave estimates are correct, both the model testdata as well as contemporary theory for wave-induced bending momentshave to be in error by a factor of about three. If it is agreedthat contemporary theory and model test techniques are better thanthis, the evidence suggests that the radar system, despite its knowndeficiencies, is closer to reality.
RECOMMENDATIONS
II The preSent ~ecome~datio~s i“”ol”e only the questiOn Of what might be
done to improve results obtained with the systems which have been dis-cussed -- under the assumption that installation of these systems is con-templated in the same, or another, large high-speed ship. Implicit inthis assumption is that the overall theoretical limitation of either sys-tem is accepted. This overall limitation is that under the most ideal con-ditions only the encountered scalar spectrum of wave elevation can be pro-duced.
llAlthough the evidence is by no means conclusive, the present investigator’ s
opinion is that the Tucker meter is not a good choice for installation ina ship of the size and speed of the sL-7 class. However, should such an
installation be required, it is recommended that the dOuble integra–tion and computing circuits of this system be re-worked. The frequencywhere serious phase and amplitude distortion occurs in the double integra-tion should be much lower than it was in the present full-scale program.It may be that the most practical approach would be to record both pressureand acceleration, and carry out an after–the-fact data reduction proceduresimilar to that employed for the radar. With or without a re-working ofthe electronics, there appears no real alternative to the full-scale cali-bration approach to the ship-wave interference effects upon the pressurehead. such trials are recOmended fOr any installation in large, high-speed ships.
llA~ noted in the conclu~ion~, the radar system installed in the Present PrO-
gram appears to have had a number of deficiencies. Despite these, it is
the opinion of the investigator that the radar- based system is pre-
ferred for installation in large high speed ships. A check of resultsagainst a believable standard would still be required.
/lIn the ~en~e ~~ed here) the “radar system” includes more than just the radar
unit itself. The various motion transducers and the data reduction proce-dure must be considered as part of the system as well. The perceiveddeficiencies appear to be largely curable. They may be considered under threemain headings, as follows:
A-28 L.
t
1’1.The Radar Unit
Questions about the internal behavior and physics of the radar unit (howit could be bettered as a radar; if when a valid return is sensed is theindicated range correct; the nature of the physical circumstances underwhich return signal is lost, etc.) are all items which are beyond both
the scope of the present project and the competence of the investigator.
All the perceived deficiencies with the unit appear consistent with the
output logic employed to deal with occasional return signal loss. Because
it is necessary to know the length of the slant range vector when computing
its vertical component, the output logic of the unit should be changed so
that this information is not lost during a voyage -- irrespective of any
return signal loss problem. The approach recommended is to hold the lastvalid range in the output register until the next valid range is acquired.It is suspected from the data in hand that the lapse of time between sig-nal loss and re-acquisition is ordinarily relatively short. The effect onthe data of the above recommendation would be to produce “notches” or flatsin the time history. Small notches would introduce mostly high-frequencynoise which is far preferable in data reduction to the ultra low-frequencynoise injected by the logic of the present unit. Large “notches” or flatsof long persistence would be relatively easy to see visually, or to detectby computer.
//2. Angles
To a fair degree of approximation the angle transducers of the pendulum
tYPe used in the present program are equivalent to body fixed lateralaccelerometers. They are sensitive to both rotation and acceleration.The basic recommendation in this area is to measure angles properly --either implicitly or explicitly. In the context of the radar system, thismight be accomplished in two ways. One option is to mount a verticalaccelerometer on the antenna and gyrostabilize both. In this case,theaccelerometer output would be correct with respect to true vertical andthe slant range would be related to its vertical component by a constantfactor. The second option would be to mount a gyrostabilized verticalaccelerometer in the radar pedestal. In this case,the accelerometer out-put would also be correct with respect to true vertical, and it would
appear feasible within current state of electronic and microprocessortechnology to make a continuous three dimensional vector correction to theslant range using the indicated angles from the gyro. It is felt thatover and beyond the technical improvement, the resources expended in im-proving and automating the angle corrections could well be repaid inreduced costs of data handling and processing due to the fewer channelswhich would then be involved.
113. Accelerations and Double Integration
In the final analysis, the phaseless double- integration scheme employedin the present data reduction was not sufficiently sophisticated. It was
unable to handle ultra low frequencies as well as could be desired. How-
ever, the basic problem was that the extraordinarily good acceleration re–solution required in some situations was not present in the data. According
A-29
Ilto the results, it appears that if the same scheme was to be used over
again, the acceleration signal out of the recording medium should have a
resolution approaching t 0.002 g. With analog magnetic tape as the re-
cording medium, this resolution might be approached in those cases where
it is most needed (mild following or quartering seas) by the use of auto-
matic gain control and the elimination of the one “g” signal bias included
in the present vertical acceleration data. It should also be noted that
the accelerometers used in the present application were probably not cap-
able of this small a resolution.
IIWhile better acceleration resolution would go a long way toward improvingthe estimation of the vertical displacement of the radar unit, it shouldbe emphasized that any scheme involving discontinuous data samples hasa low-frequency limit below which a proper job cannot be done. Perhaps,there is a practical continuous double- integration scheme which does notproduce phase shifts. However, the present investigator’s recommendationwould be to defer an extraordinary amount of effort on this problem andto accept possible errors in quartering and following seas until such timeas any second generation radar system can be fully accepted in the headand bow sea situation. “
A-30
-
TITLE/SSC REPORT NO. (Ref. 24)
Comparisons of Stresses Calculated Using the Daisy System to Those Measuredon the sL-7 Containership Program, SSC-282, SL-7-24
DESCRIPTION
This report compares stresses calculated using the ABS/DAISY finite-element
program with those measured on board the SL-7 SEA-LAND McLEAN containership.
This work was undertaken to verify the analytical procedures used in assess–
ing the strength of ships in a seaway. Comparisons and evaluation are per-formed for four different and progressively more severe technical conditions :
dockside calibration, RMS stresses in head seas and instantaneous stresses
in head and oblique seas.
The wave environment which formed the basis for the comparisons of full-
scale stress data and the analytical simulations was determined based on
recorded signals from the wave radar system; however, at the time the cor–
relation and verification study (SSC 28o, SL-7-23) had not been completed.
Once the wave environment was determined, the ABS/SHIPMOTION and ABS/DYNPRE
computer programs were used to predict ship motions, wave loads and hydro-dynamic pressures for input to the finite-element structural model. TheABS/SHIPMOTION program is a revised version of SCORES. ABS/DYNPRE whichis an extended subroutine (post processor) of the SHIPMOTION program cal–
culates the hydrodynamic pressure distribution on the wet surface of aship’s hull. The finite-element model consisted of a three-dimensionalcourse-mesh and a fine mesh used to determine the stress distribution atselected strain-gauge locations.
AUTHOR ‘S FINDINGs , CONCLUS IONS AND RECOMMENDAT IONS
(1)
(2)
The overall comparison between calculated and measured stresses forthe dockside calibration is generally inconclusive because of sig–nificant temperature differentials during the test and the low mag–nitudes of the applied loads. However, good agreement between thecalculated and measured stresses was obtained when thermal effectswere small. For future calibration tests, it is recommended thatcomplete temperature data be recorded and that appreciable mechanicalstrains be generated in the structure.
The comparison of calculated and measured RMS stresses in head seasis generally satisfactory, using both the spectrum analysis approachand the equivalent regular wave approach. The correlation usingthe former approach which takes into account the “ariation in res-ponse to different wave frequencies, shows better agreement thanthat obtained from the latter approach. However, it should be notedthat the spectrum analysis approach is valid only near the midshipsection where the wave–induced stresses are generally in directproportion to wave heights.
A-31
(3)
(4)
(5)
(6)
(7)
The agreement of calculated and measured instantaneous stresses inhead seas is generally good; the calculated stress amplitudesagree well with the mean values of the measured stresses over atime-span of two complete encounter cycles.
The agreement of calculated and measured instantaneous stresses inoblique seas is also generally good for the wave conditions con-sidered.
Based on the results obtained from this project, it can be concludedthat the existing analytical tools for predicting wave loads andstructural responses are suitable to assess the overall strength ofthe hull girder. ALl the measured stress data reduced to date fromthe sL-7 instrumentation program and all the calculated hull-girderstresses from the present study were found to be of low magnitude.Consequently, no modifications to the present hull girder strengthstandard are deemed necessary.
Regarding the structural responses, the ABS/DAISY system in its presentform is considered satisfactory for performing static analyses foreither quasi-static or dynamic loads.
In order to assess the strength of local structures and also to im-prove the current methodology, further research is deemed necessaryto improve the calculation method for external pressures (possiblyverified by model experiments) and to improve the ship motion pro-gram (SCORES) to account for three-dimensional effects and possiblyfor non-linear effects with respect to wave heights.
A-32
I
!s.-
TITLE/SSC REPORT NO. (Ref. 25)
Results of the First Five “Data Years” of Extreme Stress Scratch-GaugeData Collected Aboard SEA-LAND’s SL-7S, SSC-287 (SL-7-25)
DESCRIPTION
This report describes tbe installation, calibration and data acquisitionof scratch gauges mounted on each of the 8 ship class of SEA-LAND’s SL-7S.Preliminary data reduction is described. The data are presented inhistogram form for the various ships, years and routes (Pacific and NorthAtlantic) . No attempt was made to analyze the data or categorize thescratches according to weather encountered.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
This report did not contain detailed data analysis and no conclusions orrecommendations were offered.
A-33
“q-
TITLE/SSC NO. (Ref. 26)
“Ship Motions and Capsizing in Astern Seas”. This is not a SSC or SL-7
document but is a paper presented at the 10th Symposium on Naval Hydro-
dynamics, Office of Naval Research, June 1974.
DESCRIPTION
This report describes the analytical and experimental study of ship motions
and capsizing in following seas conducted at the University of California,
Berkeley for the U.S. Coast Guard. Extensive tests were conducted using
two radio–controlled models in the wind-generated seas of San Francisco Bay.The models were the ANERICAN CHALLENGER class of cargo ship and the SL–7class container ship. Comparisons of the experimentally determined motionswith a linear strip theory prediction are presented for both types of ships.A time-domain,numerical simulation program for motions and capsizing wasused to investigate motions in a variety of wave conditions and was com-pared to the experimental results.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMMENDATIONS
The analysis of linear and quasi-linear one-dimensional roll modelsrevealed motion anomalies not apparent from the usual nonlinear shipmotion theory. The authors concluded that linear ship motion can onlybroadly outline areas of speed, heading, and ship characteristics whichmay lead to trouble. Classical ship motion theories which are augmentedby some nonlinear terms may reveal phenomena, not apparent in results oflinear theory, which may lead to severe motion. The ability to predictcapsizing is still not available through such theories.
A-34L
TITLE/SSC REPORT NO. (Ref. 27)
Capsizing Experiments withBay. This’ is not a SSC orReport.
DESCRIPTION
a Model of a Fast Cargo Liner in San Francisco
SL-7 designated document, but is a Coast Guard
This report describes a program of model testing in the open waters of SanFrancisco Bay. The program had as its objective the study of ship motionproblems including capsizing and control perfonnance in a heavy seaway.The equipment, testing techniques, and data acquisition and processing aredescribed. Some preliminary results from simple statistical analyses of
the data are also given.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOMMENDATIONS
Observations of the behavior of a model of the AMRRICAN CHALLENGER classof cargo ships have enabled the authors to identify three categories ofcapsizing: low-cycle resonance, pure loss of stability, and broaching.All three modes are strongly influenced by the reduction of the ship’sstability when a wave crest is amidship and all are most likely to occurin a following to quartering seaway.
The conclusions consisted primarily of an evaluation of the instrumentationused to power and control the model and data-collecting techniques appli-able to open-water model testing.
TITLE/SSC REPORT NO. (Ref. 28)
“A Time-Domain Solution to the Motions of a Steered Ship in Waves. “ This
is not a SSC or SL-7 designated document, but is a Coast Guard ReportNumber CG-D-19-73.
DESCRIPTION
The problem of ship motions in waves is formulated in the time domain bymeans of a convolution integral which relates the ship motion response toarbitrary exciting forces, under the assumption that the response is linear.The convolution integral is evaluated numerically to obtain the ship motionsat discrete intervals of time.
Frequency independent nonlinearities of arbitrary form are incorporated intothe model by considering them as part of the arbitrary exciting forces. Non-linearities with time lag, such as thnse arising from rudder motions, areparticularly amenable to this treatment. Nonlinearities that are functionsof the instantaneous motions of the ship are approximated by continuouslyextrapolating the ship motions. llus, one is able to include frequency-dependent linear force terms in what amounts to a stepwise solution of thenonlinear equation of motion, a capability not available in the conventionaldirect numerical integration techniques exemplified by, e.g. Runge-Kutta.
AUTHOR ‘S FINDINGs , CONCLUSIONS AND RECOMMENDATIONS
The author cnncluded that the numerical techniques for simulating the steeredmotion of a ship moving through a random seaway hold promise as a tool forstudying the behavior of ships in severe wave conditions where large ampli–tude ship motions exist.
The recommendations included:
(1) Additional nonlinear terms including nonlinear roll restoring moment withwave effects to improve the prediction at large roll angles, and non-linear coupling between roll and heave or pitch.
2. A more precise determination of the terms in the convolution integral
is needed with experimental verification. These experiments should
include the measurement of impulse forces and responses, and wave
exciting forces and responses.
A-36
TITLE/SSC REPORT NO. (Ref. 29)
“Development of a Time-Domain Simulation for Ship Capsizing in FollowingWaves. ‘“ This is not a SSC or sL-7 designated report, but is a U.S. CoastGuard Report Number CG-D-28-74.
DESCRIPTION
This report describes the development of a time-domain computer simulationfor ship capsizing in following waves. A survey of the recent literaturein this field is presented. The formulation of the present approach isdiscussed, along with computer program limitations and assumptions. Theprogram developed is used to study the phenomenon of low-cycle roll reson-ance as demonstrated by a two-dimensional section forced heave motion andby a fast cargo liner in following waves, both regular and irregular. Theeffect on capsizing tendency of variations in ship characteristics, initialconditions, and wave conditions is investigated. Qualitative comparisonsof results with open water model experiments of the AMERICAN CHALLENGERclass of cargo ships is presented. Finally, the potential application ofthis program to the determination of merchant “essel stability criteria isdiscussed, and recommendations are made for further work.
AUTHOR ‘S FINDING, CONCLUS IONS AND RECOMlfENDATIONS
The authors found the qualitative agreement between time-domain simulationsresults and the results from the AMERICAN CHALLENGER open water model teststo be encouraging. The authors further concluded that the program inits current form can be used to simulate capsize situation quite accuratelyunder pure following wave conditions.
The recommended improvements to the time-domain simulations included a moresophisticated numerical integration technique and the investigation of non–linear roll damping effects.
The authors recommended that the program be used to determine criticalregions of operation from the stability point of view which would helpestablish effective stability safety standards for all vessels.
A-37
TITLE/SSC REPORT NO. (Ref. 30)
“Structural Analysis of a Containership Steel Model and Comparison withthe Test Results. ” This is not a SSC published document. This documentis presented in SNAME Transactions, 1976.
DESCRIPTION
This paper presents the comparisons of the steel and vinyl models of theSL-7 containership hull and a finite-element static analysis using themodel test loads. A course mesh model of the hull was developed and afine-mesh analysis for different parts of the deck structure was alsopresented. The hull was tested under vertical, lateral and torsionalmoments. Stress distributions, particularly in the deck region, are pre-sented and investigated from the different types of analysis.
Estimations based on beam theory are also presented for the pure verticalbending cases.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECONMENDATIONS
The authors concluded that the finite-element model used to represent thesteel model in the study was considered satisfactory for examining res-ponse of a hull girder to both bending and torsional loads. A model offiner mesh is required for determining the distribution of warping stresses,
in comparison with that of bending stresses. They also observed that theinstallation of a heavy faceplate around the cutout on the deck at a hatchcorner can help to reduce significantly the stress concentration factor forthe structure configuration.
The author recommended that:
(1) In the design of containerships, more attention should be paid to thetorsional rigidity distribution along the hull.
(2) Future attempts should be focused on establishing simple methods toestimate the hatch opening distortion as a function of the distribu-tion of torsional moments and the basic structural configuration ofthe vessel.
(3) Finite-element analyses of containership structures should be con-tinued until a simple and reliable method is established for the pre-diction of torsional response of open deck hull girder. This isespecially true for local structural details, such as hatch cornersand connections near deck openings and other structural discontinuities.
(4) Full-scale measurements aboard the sEA-LAND McLEANwere collected forthree years. Correlation between the analytical results and the full-scale measurements would be beneficial in establishing guidelines forfuture designs.
LA-38
TITLE/SSC REPORT NO. (Ref. 31)
Evaluation of sL-7 Scratch–Gauge Data (This report will be published as
a SSC document, but exists as a Draft Final Report, Project SR-1268) .
DESCRIPTION
This report describes the evaluation of the scratch-gauge data taken aboard
all eight of the sL-7 class of containerships. This project assesses the
value and application potential of the scratch-gauge data base. The pr i-
mary objectives of the project were to evaluate SL-7 scratch-gauge data as
a basis for extreme load prediction, to determine correlations with electri-cal strain-gauge data recorded on the sL-7 SEA–LAND McLEAN, and to recommendwhen and how many scratch gauges can be reco”ered for placement aboard otherships. The study also investigated a wide spectrum of applications of thescratch-gauge data and the gauges themselves. The data analysis included:
(1) Discussion of the measurement phenomena including what types of loadingsare represented by the scratch-gauge recorders.
(2) Statistical analysis of scratch-gauge data for all eight sL-7 container-ships in Pacific and Atlantic oceans. The statistical analysis in–eluded examination of the data with respect to statistical extreme pre-diction models.
(3) Comparisons of the electrical strain gauges to the scratch gauges andevaluation as a possible alternative to electrical strain gauges.
(4) Miscellaneous applications that include tracking of mean stress, shortterm statistics and the effects of corrosion.
AUTHOR’ S FINDINGs , CONCLUSIONS AND RECOIO.IENDATIONS
The author presents several conclusions and recommendations that arepertinent to the applications of scratch gauges. In summary they include:
(1) The scratch-gauge recorders produce data that represent the sum totalof experience of strain that results from various types of shiploadings (i.e. mean stress, wave-induced stresses, whipping, thermaleffects, etc.)
(2) The scratch-gauge data easily lends itself to the various methods ofstatistical inferences described in the report. The extreme valuesderived can provide guidance to design of similar ships or structuralmodifications to the existing SL-7 class. This is contingent upon shipservice under operation and environmental conditions similar to thoseunder which the scratch data was acquired.
(3) The scratch-gauge data can be used as an alternative to electricalstrain instrumentation if total combined load is sought. The data
A–39
cannot be used ~0 predict wave-induced 10ading OnlY Or tO validate
methods which theoretically predict only wave–induced loads.
(4) The scratch-gauge data records provide a way to track mean stressover a long period of time. However, there are significant diffi-culties involved with such a procedure.
The author’s recommendations included the possible future use of thescratch gauges and scratch-gauge data already obtained. These included
possible use for other sSC projects on Still Water Bending Moment Determi-nation and Ship Structures Loading in Extreme Waves.
A-40
TITLE/SSC REPORT NO. (Ref. 32)
Fatigue Load Spectra Development for Ship Hulls. This information willbecome part of a report that will be published as an SSC Document, ProjectSR-1254 , “Fatigue Considerations in View of Measurement Load Spectra.“
DESCRIPTION
This report describes several methods for developing load spectra applicableto fatigue testing. The primary purpose of the study was to develop amethod for selecting fatigue load spectra for ships and to use the spectraas input to fatigue crack-growth analysis. Additional information is pre–sented for the development of a long-term combined statistical stress dis-
tribution which would then represent a total picture of the stresses ex-perienced by the ship during its lifetime. Consequently, the resultingdistribution can be used for fatigue analysis. The method for developmentof load spectra for ship hulls was illustrated using the SL-7 SEA-LANDMcLEAN midship bending stress data base.
AUTHOR ‘S FINDINGS, CONCLUSIONS AND RECOMMT,NDATIONS
The conclusions and recommendations included :
(1)
(2)
(3)
(4)
(5)
The state of initial mean stress in the sL-7 has been lost by thezeroing procedure and upon departure for each voyage in an effort toa“oid signal saturation. It is recommended that future instrumenta–tion programs incorporate a procedure for recording the magnitude ofthe gauge reading before it is zeroed.
The development of long-term statistical stress distribution based onobserved wave height, Beaufort number, wind speed, or sea state, hasobvious disadvantages which could be minimized if accurate wave heightinformation was available.
The Root Mean Square (RlfS)of the high-frequency wave-induced stressesshould be calculated and incorporated as part of the presentation inthe summary sheets.
Further analysis should be conducted to develop a rigorous method for
combining the mean stresses (initial, varying, thermal, etc.) with thelong-term statistical stress distributions for the wave-induced stresses.The method developed here represents a reasonable “first-cut” approachto the problem.
An invesgitation should be conducted to determine in what manner thehigh- and low-frequency wave-induced long-term statistical stress dis-tributions may be combined so that they are representative of combinedstresses which in turn affect the fatigue life of a ship ‘s structure.
A-41
(8) The combined long-term statistical stress distributions do not retainthe stress peak-to-trough sequencing information present in measuredstress time histories. This is a major disadvantage in utilizing acombined long-term statistical stress distribution to investigate thecrack-growth retardation phenomenon.
A-42
TITLE/SSC REPORT NO. (Ref. 33)
Examination of Service and Stress Data of Three Ships for Developmentof Hull Girder Load Development, SSC 287.
DESCRIPTION
This is a follow-on project tn SSC 240, “Load Criteria for Ship Structural
Design, ” which proposed methods for the estimation and superposition of theprimary loads and performed sample calculations for one conventional dry
cargo ship. It involved the following bending moments:
* still-water due to weight and buoyancy● ship’s own wave train9 quasi-static wave-induced, vertical and lateral combined* dynamic loads, including slamming, whipping and springing9 thermal effects
In this report,the service and full-scale stress data of three larger and/or faster ships (including the SL-7 SEA-LAND McLEAN) are examined for thepurpose of the eventual development of hull–girder criteria. The purposeof this study was to analyze the service experience of three types nf ship,which included a large, high-speed containership (sL-7), an oceangoing drybulk carrier, and a very large crude carried (wCC) . The examination islimited to extreme midship bending moment loads which are related to theultimate strength.
AUTHOR ‘S FINDINGS, CONCLUS IONS AND RECOlfMENDATIONS
The authors concluded that the still-water bending moments can be determinedprobabilistically; however, considerable additional information on loadingconditions must be gathered in order to determine the statistical distribu–tions. They also indicated that additional effort is required to determinethe suitable probabilistic expression and the synthesis of a method forincluding the contribution of vibration to the extreme load.
A-43
TITLE/SSC REPORT NO. (Ref. 34)
Evaluation of Full-Scale Wave Loads. This is not a SSC published document;
it was prepared for Panel HS-1, SNAME.
DESCRIPTION
The results of midship bending stress measurements made on 22 ships(including the SL-7 SEA-LAND McLEAN) of various types have been convertedto a bending moment coefficient, (based on RMS stress for given recordingintervals) plotted and compared. Trends of wave bending moment with shiptype, trade route, length and fullness are shown.
AUTHOR’ S FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
The conclusions summarized the observed trends and made several recommenda–tions for future stress-data measurements. The author recommended thatfuture full-scale stress measurement systems be of the computer self-contained
tYPe Presently in use for operational hull response monitoring. It was alsorecommended that regardless of the instruments used in making full-scalemeasurements, it is imperative that the trade route, speed, ship-to-waveheading, wave height observation and ship loading condition be routinely re-corded with all measured data. The recommendations included a discussionpertaining to the information needed to calibrate the stress predictionmethods that have been developed to date. These recommendations were briefbut are pertinent to future research programs.
(1) Comparison of long-term (ship-lifetime) extrapolation of measured stressdata with long-term predictions using a“ailable statistical predictionmethods.
(2) Use of full-scale measurements made simultaneously with nearby wave-buoy measurements.
(3) Development of reliable shipboard wave-data instrumentation when placedaboard ships along with stress instrumentation.
A-44
APPENDIX B
SL-7 RESEARCH PROGRAM DATA BASE DESCRIPTION
B.1 RESEARCH PROGRAM, DESCRIPTION OF THE DATA BASE
The information presented in the references listed in Table 3–1 forms thebasic description of the total SL-7 research program data base. Themajority of the documents are available from the National Technical Informa-tion Service (NTIS) in Springfield, Virginia. Each document is relativelycomplete with respect to the individual program. The full-scale instrumenta-tion portion of the program is generally of greatest interest to the marineresearch and development community since it represents one of the mostextensive instrumentation programs undertaken to date. The objective ofsummarizing the sL-7 data base is to provide information for designers andresearchers contemplating the applicability of the data base to other pro-jects and to those planning similar full scale instrumentation programs.
Technically, the instrumentation package installed on the SEA-LAND McLEANconsisted of hull structural response instrumentation, environmental wavedata collection instrumentation and the extreme stress instrumentation.The latter two elements of the response instrumentation have been desig-nated separate entities by SSC and the data collected were also presentedas separate projects. In this report, the same organization will be followedwith discussion of the analysis and reduction of environmental wave data andscratch gauge data in the evaluation section. In this section, the database obtained from the full-scale hull structural response instrumentationpackage installed aboard the SEA-LAND McLEAW will be described.
Responsibility for the design and installation, operation of the system,and the collection of data on the SF&LAND McLEAN was assigned to TeledyneEngineering Services (TES) of Waltham, Massachusetts. The instrumentationpackage of the SEA-LAND McLEAN, a descendant from the BOSTON instrumentationprogram (40), also designed by Teledyne, has additional, more complexmeasurement requirements. A description of the system and its installationis contained in SSC-238 (1).
The design and installation phase took place during the period prior to theship entering service. Data collection began in September 1972 and continuedfor three sequential winter seasons in the North Atlantic.
The primary information objectives to be met through the shipboard measure-ments were as follows:
(1) Midship vertical bending stresses of the deck, neutral axis and tanktop of the midship section.
(2) Torsional shear stresses.
(3) Principal stresses at hatch corners.
B-1
.
(4) Vessel pitch and roll.
(5) Gross hull accelerations.
(6) Accelerations of forward and aft deckhouses.
(7) Longitudinal stresses at the deck and tank top of the forward endof the cargo hold.
Figure B-1 depicts the general instrumentation layout on the SEA-LAND
McLEAN and References 1 and 5 contain detailed descriptions of the instru-
mentation sites and locations. The data from the instrumentation channelswere supplemented by logbook entries of observed environmental and opera-tional conditions, such as wave height estimates made by ship’s officers,who had been instructed on wave observation techniques as part of a trainingprogram prior to serving on the SL-7S.
The outputs of all the various sensors were not recorded continuouslybecause space and fund limitations dictated that only two fourteen channeltape recorders be installed. One recorder was dedicated to record 13channels of data always from the same sources. The other recorder wasused for 13 independent channels of data in four different modes of opera–tion for a total of 52 channels of information from cyclically selectedsources. The fourteenth channel on both recorders was reserved for com-pensation. Data were recorded for a total of two hours out of every fourhours of ship operation. During this period, the cyclical recording modeoperated on a one-half hour interval for two hcmrs out of e“ery four hourrecording cycle. These one-half hour periods were then assigned indexnumbers. See Figure B-2 which shows the calibration and data recordingsequence. The channel assignments and recording modes are indicated inReference 1. Ouring periods of high seaway loads, the data were recordedcontinuously. This type of additional recording mode was actuated whencertain pre-set strain levels were exceeded.
A significant amount of new strain-gauge instrumentation was installed forthe third season of data acquisition (10). The location of this gaugingwas based on the observation of damage incurred in the first two years ofvessel operation. Specifically, radial cracks from the forward and some
aft hatch cOrners, green water set–down of the forecastle deck, and defor-mation of some bow flare plating had been experienced. In an attempt tocharacterize the loading in these areas, additional strain gauges wereadded. This instrumentation was included in the rotational schedule ofthe cyclical recorder. The strain information obtained from the gaugeslocated in the area of the radial cracks could provide valuable data uponwhich fatigue studies could be based. However, at this time the data havenot been reduced or analyzed and exist only in analog form as does the vastmajority of data collected aboard the SL–7 SEA-LAND McLEAN.
Several important features about the data should be mentioned. The stresses,motions and accelerations were inferred from the analog voltage signal using
appropriate calibrations at the start of each recording interval. SeeFigure B-2 for a typical strain recording. The strain measurements are not
B-2I
L-
r:,,,:!
:,!4---
‘1’,-...,,1,II!,
!9
.,c%’
B-3
Figure B-2
THE STRESS RECORDING TECHNIQUES IJsED BY TELEDYNE ENGINEERING SERVICESOK THE ST.-7 SEALAND McLEAN
[ ~ “ -m“‘r”+’‘r-l-” ‘r+’ ‘r~ 2“s ~“ ‘r”4
20 min.of da,.
tart 20 min.of ~. ~i”, ~: ‘& .=
.yageof data
0’ = a w _ Ill]
&,erval @ @ @ 4off
@ ‘“”
c imeACTUAL RECORDING
~ “ ‘“U’ ~20 minute recording ‘inter val,,
) I
I I
I
plL.J.‘h A/Jh ,4combined signal
,’s
o
ca$i”ni &/
peak. to-tcough cycle
hi@ frequency w,veinduced signal ,Hfirstmode compone. c,>(stresses filte..d)
EXA)PLE OF REcORDING INTERVAL AND DATA REDUCTION ,.,)
?.. stress level was :al..l. ced fr.. dam and referenced t. the start .f the ..Ya% he.g,a. ge. .. . . zeroed. Shifts in the mean stress were recorded after the gauges were zeroed.
B-4
.
absolute levels of stress in the structure, but rather the relative dynamic
strain. The absolute value of strain includes, in addition, the combina-
tion of residual strains present at the time the strain gauges were instal–led. No method of reconstructing these residual strains is available.
The dynamic strains do not include the still water or initial mean strainresulting from cargo and/or ballast loading upon departure for each voyagebecause the strain gauges were zeroed to avoid signal saturation and noprovision was made for recording the initial mean stress levels. Thisinformation is not available in any form for analysis. (This is an ex-tremely important point if comparisons are to be made with static calcula-tion of wave-induced bending moments. ) After the vessel left port for avoyage, the gauges did record the “arying mean strain which was made up ofchanges in ballast, consumables, fluid speed and thermal effects. An exam-ple of this may be seen in the upper part of Figure B-2 for the recordingintervals 1-5 showing different mean strain levels for each interval.
Each 30-minute measurement interval is preceded by calibration signals andzero reference information as shown in the lower part of Figure B-2. Themean strain level for each 30-minute interval was computed for each of thestrain channels reduced. This mean stress varied from interval to interval.
The wave-induced stresses fluctuated about the varying mean stress during agiven 30-minute recording interval. The wave-induced stresses consisted oftwo basic components; the stresses that were induced by the waves occurringat approximately the frequency of wave encounter, and the stresses super-imposed on the wave-induced stresses which are at or near the first mode hullgirder response frequency. These high-frequency stresses are a result ofimpulsive loadings due to a representation of both the low-frequency andhigh-frequency wave-induced stresses appearing in the lower part of FigureB-2.
Large amounts of stress data have been obtained from the sL-7 full-scaleinstrumentation program. The method used in data collection is orientedheavily toward collecting large amounts of data to form a substantial statis–tical sample. In fact, the data collection and reduction techniques were acarry-over from previous full-scale instrumentation programs in which theobjective was to obtain a large statistical sample so that the data couldbe extrapolated statistically to form a lifetime loading picture and thusaid in evaluating existing load criteria (L/20 wave, etc. ).
B .2 SL-7 INSTRUMENTATION DATA REDUCT ION AND ANALYSIS
The SEA-LAND McLEAN instrumentation data collection program generated rawdata in two forms :
(1) Magnetic 14-track tapes containing analog strain, sea characteristicsand ship operating parameter signals
(2) Manually recorded logbook data describing sea, wind, wave, and weatherconditions at four-hour intervals.
B-5
i
TWO formats were available for display of analog data. For quick ship–
board review, each channel could be played back on an oscillograph at
relatively high speed, with a low paper speed. The resultant compressed
time-history hard copy record could be reviewed to observe signal peaks,
relative levels, and overall variations . However, details of the wave
form could not be seen. After returning the analog tapes to Teledyne, a
more detailed review of selected data channels could be conducted usingexpanded time-history hard-copy oscillographic records made at slowertape speeds which preserve the details of wave form.
Procedures and computer programs described in References 41 and 42 wereused to place the logbook data into digital form, to digitize selectedchannels of analog data, and to collate these sets of digital data ontodigital library tapes. Subsequently, summary tapes were prepared whichcontained reduced transducer signals in digital form. These summary tapeswere derived from the library tapes to facilitate data review and parametricanalysis. The summary tapes contain the logbook information and reduced datafor each interval. The reduced interval data consists of the Root-Mean–Square(RMS) of the Peak-to-Through (P-T, see Figure B-2) wave-induced stress,maximum P-T wave-induced stress, number of zero crossing wave-induced cycles,maximum P–T first mode stress and number of “bursts” of higher frequencytransients per interval. Table B-1 displays the SSA-LAND McLEAN instrumen–tation program data in its various formats as it exists in the Teledyne SL-7library. It is noted that with each succeeding season, fewer channels ofanalog data have been digitized. An interview with Teledyne personnel re-vealed that each season fewer channels were digitized simply because of thelack of requests for the previous season’s digitized data.
For each transducer signal listed in Table B-1, the following describes ingreater detail exactly what data are contained on its associated digitallibrary tape(s) . Since most large-magnitude stress records, especially thoseassociated with slamming and similar dynamic events, can be separated intotwo components - wave–induced and first-mode two-noded vibration (i.e.whipping or springing) - and since each of these components can be charac-terized by its frequency, appropriate filtering arrangements can be appliedto isolate each phenomenon’s contribution to the overall stress record.Such a procedure was used in processing the SEA-LAND McLEAN analog records.On playback, the analog signal was filtered through a low-pass filter witha 2 Hz cutoff to eliminate high frequency vibratory effects and other noise;the remaining signal was then processed in three ways:
(1) Through a 0.56 Hz to 2 Hz band pass filter to isolate the firstmode component (the first-mode frequency of the SEA-LAND McLEANat normal operating load is 0.80 Hz) .
(2) Through a 0.01 Hz to 0.22 Hz band pass filter and two subsequentO.22 Hz low pass filters to isolate the wave-induced component.
(3) Unfiltered to yield combined wave-induced and first mode-signals
This filtering process is pictured graphically in Figure B-3.
B-6
,
DATA ACQU ISITION SFASON !
SEASON I
—
● OCT 72 - APR 73
● Voyages 1 - 12
SEASON 11
● sEP 73 - MAR 74
● Voyages 25 - 38
SEASON III
● JAN75-NAR75
w Voyages 59 - 61
TABLE B–1
s . ‘S, SBA-LAND McLEAN
SUMMARY OF INSTRUMENTATION PROGHAN DATA AND DATA FOBMATS
THAT ARE PRESENTLY AT TELEDYNE ENGINEERING SERVICES
ANALOG TAFE”S/LoGBOOK
●
●
●
●
80 Analog Tapes
Full Set of LogbookOata
94 Analog Tapes
Full Set of LogbookData
● 34 Analog Tapes
● Full Set of LogbookData
DIGITAL LIBRARY TAPES
● 8 Analog Channels Digitized
Longitudinal Vertical
Bending‘al Shear MidshipsRoll
PitchForward AccelerationVerticalLongitudinal Horizontal
Bend ing
Shear Forward PortShear Forward Starboard
● All Logbook Data Digitized
● 3 Analog Channels Digitized
Longitudinal Vertical
BendingTorsional Shear Midships
Forward Acceleration
Vertical
● All Logbook Data Digitized
SUNMAKY TAPES
●
�
One Summary Tape perdigitized channel which
contains interval summarydata and logbook data.
(an example of sumnarytape output is shown in
Figure B-9)
. One Summary Tape perdigitized channel which
I
1- contains interval summarydata and logbook data.(an example of sunmary taroutput is shown in
Figure B-9)
. I An~log channel Digitized I . One Summary Tape pe.
Longitudinal Vertical ~
digitized channel which
Bending *contains interval summarydata a“d logbook data.
] (an example of smmary● All Logbook Data Digitized , tape output is shown in
I Figure B–9)— ——
*The longitudinal vertical bending stress is the only stress information reduced to digital formfor all data acquisition seasons
LOWPASS
DataPlayback
d
D
*3 db Point I
T(
In0.56 z
All Rolloff~at 24db/Octave
All Frequenciesat Real Time
- ‘:::0.01 0.22
FIRSTMOOE
I
LOUPASS
@
b 0.22
WAVE-INOUCEO ORIGINAL
Figure B-3 FILTERING PROCESS USED BY TELEIKNE ENGINEERING SEK:ICESFOR Al!ALffi sIGX,W DIG IT Iz1lTG FOR DATA OBTAIXll ON TSE SL-7 WA-MITE WLZAN
Reference 8
B-8
.
The three analog signals were then digitized at a sampling rate of 10
readings per second. Since only the first 20 minutes of each interval
is processed, each of the three filtered signals (wave-induced first mode,
and combined) generated 12,000 data points per interval. These sets of
12,000 data points comprise the digital transducer record. The computer
program which generates the basic digital data record conducts additional
calculations and operations to produce the digital library tape. A flow
chart showing the digital library tape generation process is shown in
Figure B-4.
For the wave-induced component, P-T values are calculated, stored, the
number of P-T values counted and the RMS value of P-T wave-induced stress
for the interval is calculated. The mean value of stress for the inter-
val relative to the first interval of the pass (where a pass is a complete
voyage’s record for that transducer) is determined. Each P-T value is
compared to the previous maximum and the maximum P-T value for the inter–
val is retained. These values are stored as interval summary data.
The first-mode stress P-T data were calculated. When a predetermined
threshold value of 600 psi was reached, the “burst” was initialized and
counted, then the maximum P-T value for the interval was recorded
Next, the digitized transformer data and the interval summaries are merged
with the digitized logbook data. This process of generating the digital
library tapes is summarized in Figure B-4.
To facilitate efforts such as parametric studies , where various logbook para-
meters are keyed to summary data, significant efficiency in tape reading can
be achieved if the basic digital waveform records (12,000 point data sets)
are deleted from the tape in use. To this end, sunnnary tapes have been pro-
duced from the Library Tapes by deleting the digital records of wave-induced,
first mode, and combined analog signals. The remaining information, interval
summary information and logbook data is then available in a compact format
for parametric–type analysis. The summary tape information is indicated onFigures B-4 and B-5.
The various examples of data presentation formats indicated in Figure B-5
are examples of the data processing capabilities of Teledyne. Table B-1
summarizes the channels of full-scale data that have been reduced to date.
Figures B–6 to B-n present examples of the various data formats in additional
detail. An example of stress time history for the longitudinal vertical
bending stress (LVBS) is shown in Figure B-6. This information was produced
from the analog signal as recorded on the SEA-LAND McLEAN. An example of a
project logbook entry form is shown in Figure B-7. This information was
later digitized for further use in computer analyses. Figure B-8 depicts a
sample of the digital library tape where the digitized logbook data and
digitized P-T stress information are presented for a given 20 minute inter-
val of recorded data. A selected example of the summary tape information
is presented in Figure B-9. ‘he summary tape contains index information,logbook information and reduced interval data for a given channel of interest. ,
This information may be obtained from Teledyne in computer print-out form and
represents a manual method for access to the data that has been digitized
B-9
p
ANALOG ANALOG
TRANSDUCED TRAXSDLCED
s lGN.4L SICNAL
Signal Playback
LOW PASS I FILTERIIG
I
BAND PASS SETWORK
FILTERs4
WAVE INDUCED FIRST MODE COMB lNED wAVECOWONENT CIWT.ONEVT INDUCED & FIRST MODE
I 4’ANALOG TO
+- DIGITAL CONVERTER
12,000 POINT 12,000 POINT 12,000 PO lNT
DATA RECORD
DIGITIZING
DAT& RECORD DATA RECOSD
PER PER PER
INTERVAL INTERVAL INTERVAL
*&, “ ~ . ‘;,,
. 2D
o Date, time o Average wave height..
0 S... p.sic ion o Average swell height :
0 course o Average swell lengtho Average speed o Average swell direction
z
2LOGBOOK DATA
o Average R. P.M. o Barometer readingo True wind speed o Sea Temperature ;
o Beeuforc Sea State o Air Ten!Peracurenumb e r o Weather conmer. t (overcast,
o Relative wave direccio. rain, etc. )
Data logged every 4 hour,
Figure B-4 Generation of Digital Library and Summary Tapes
B-10
.
Figure B-5
EXAMTLEOF DATA PRESENTATIONFI)mTS
The d.?. formats indicated here are the presentation of the present data processing
apabi liti., of Teledy.e. T.ble B-1 presents. s.~.,y.f thed.tac~.,~,,ad. i,~a,tthe.na10 ~a~ ~OrW.1.lDATA DATA PROCESSING SAWLE PREsENTATION FORDATAANALYsIS
I 1
Environmental DataLogbook from Ship
Measure maximum value per intervalN. details
Study detailed combination of frequency
c.mPO.ents in 0.. tr...duce=
study instantaneous phase and amplituderelationships of several transducers
r.——— ___ __
I‘\ COMPUTER
I
a
xm-~ ml ~
(SeeFigure B-7) IReproduce logb.. k
I
El. Tab.lac ions of R,. P.... c...——— — P.tat ions and logbook data
— — . . P.. tial logbook data.
alone for reference&+.e (See Figure B-9)
m
,/”“+’- P.,anletrf,s,udy plot.
Se. Figure
B-10
m
Spectral plotsSPECTR4 = (Se. ,igur, B-II)
COMP.T.H.NS \ ,Omp.t.,,.rrel.ti...
of spectral .e,u~,.with logbook data
1 ISHOWN FOR COFITARISON
I I f
m; 1
Manual nmas.rment of I Tabulation in Hist. g.,.
,_ _ :r:c:’::~~ _ /_ _’”: _ _
N.nual measurement enter inc.
Scratch gauge data * ..mp. ter (G&A) (limited) ,m1“ Statistical analysis
paper tapes(See Figure 4-6
* The Logbook entries at Teledyne are for the scratch gauge data recorded
for the first three seasons on the sL-7 SEA-LAND McLEAN ~.
B-II
B-12 ~.
DATA UX
~~ s~~21 SWSLL
g *I Ejl ,e~,ve *ergtar El El ❑Sea Air Weather
No. Height! Length Direct . ReadinS Terr.p. Temp.
—. —-——L———__l_——. —_ l_____ \-2 i ._._._
Reference 8
Figure B-7 Sample Logbook Entry
18sue: 1212i68
E %ifE?iknze:”Initiale Speed, Chan~e of BallM t, S1--,
ming, Change Tape, Reel Nub..)(Have buoy launching)
k-o ?:; (z.; ;+.-<Gb’z/z Y <
a
,=DH8ccc-<. # ~~G; ‘ ‘
‘f?3A-.3.d.?-6- #,#L’G>/’I- ,:<-7-’5
I
-_..—.__—-... -. _ __ I
PAGE ●
31 G11AL IAPE 3 MCLEAN 1’9 73-1974 SE45UN MIDSHIP VERTICAL BENDING
SEA LAh U MC LfA$4 32h01-071- 7*01 -14-74 EIUt:V CI>11AVE14 10 tL1lb.3ET+4
NJ MOLU OF CVCLLS = 182
CHANNEL 8
TAPES 143. 145 AND 1+7
Am~:G Lmy I/tL REL n$yE REL S.ELLSHIPS WI:P WIND .hvr S;tI~L LENGIH SEA
N4!43EP N(IM DAli LA T17UDE COURSF DIR cIR SCCS FEET lEMP .EAIMER
TRIP INTERVAL TIME LONG[ lUDE ~;~~; SEA REL .;:~fg~~ Sfi;LL ~;~fiM ~~flpN (IM GMT sTAIE wINO
KTS sPEED FEET FI FEET HGKNOIS
4CLEAN 147 035 01-13-7k 40-17 N32W 004
274 121.0 041S 041s 018S 0400 69 OCAST RAIN
1600 056-29 N 29. u 09. 45 20 .018 29.96 039
WAVE lNDUCLD PEAK 10 TROUGM 1NFORMA11ON
3792 *325 302 t 2103 4621 :::; 3199
2073 4740 1717
4147. 5302 . 4458 3021 4!17 ::::
6013 4532 12783 11479 6850 3525
y
4058 6421
+517 5762 ~~?~ 3910 ;::: 4043 j:;: 6,58 7569 331e 1185 2251 2918
lfJ36 11)07 2666 707)0 4160 1807 4665 5243 1422 3140
K4384 5362 ::;: 7;:;::;;
bb50 9013 .915* ~;:~ ----- ~~~:..... 3806 ~~~; 8976 1281
3792 1866 3614 6606 3199 1629 ,2!30
7213 .ll;~ 2844 5125 7110 4503 2399 2962 3081 4b77 2786 2251
b177 5668 9524 1:::: 10265 :::: 3555 3436 2458 2*88 4088 3332
6177 2725 2014 1096 6747 5139 :::! ._ W; 3792 2666 1185
839n 7035 4503 1659 2281 3643 3367 7435 3095 3081 1111
2133 1896 1836 1599 *917 3703 5680 :;:: 2162 2916 1792 3436 2932
2133 6932 11020 5125 1836 47io 2903 2370 1303 2133 3095 1111
2064 1777
Figure B-8 EXAMPLEOF PE~ TOTROUGHD~~~REDUcTIONOF sL-7s~-L.~DMcL~N ~lDsHIPVE&TIcALBENDINGsTREss
1717 13621186 22211303 leO15214 32505125 4169*088 24803169 37924295 49171422 50951896 .9084947 34961.936 3140
~, ..
I
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;!1
1 1,
,,.,,
i.
B-15L—
.
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-.. . .4 II
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2:820b2 -.?81
b t,. .. -----
“MOU In -HEAVY vircn2111J0 -621
61 MOD 70 llf AVV IJll AH______3H01 -514
bO 14Ull lCI HEAVY PITCH324/ . ‘~b 2.... . . . . . .
44 Mt2:9# HE, AVY P llCM3096
. .
Figure B-9 (con’t) PARTIAL SUMMARY SHEET - SL-7 SECOND SEASON,
VOYAGE , 32W
- r-””””-”’””“-
B-17
.
Tape 143, Interval 9Ship Speed=31.s K~
Beaufort 9Bow Seas
MIS Stress=O.72 Kpsi0.6- I!aximumlji~r~ti~n
Double Arnplftude=l.3 Kp~i
0.4 -
0.80HZ
0.2-
/
o I 2 3 4 ; “7
CI rcular Frequency, Rad/Sec
Figure B-II Sample Stress Spectrum: SL-7
Reference 33
B-18
I
L
thus far (see Table B–1 for the types and amounts of data that have been
reduced to date) . Parametric plots may also be obtained from the Summary
Tape information. A sample parametric plot is shown in Figure B-10.
Figure B–II depicts a stress spectrum calculated for a recording interval.
After digitizing and reducing the analog data to library and summary tapes,
various data presen’sation formats may be utilized to facilitate analysis.
These formats fall into three categories:
(1) tabulation of the transducer and/or logbook data
(2) parametric study plots
(3) spectra computations
These tabulations can be a full listing of logbook or transducer data or
can be parametrically selected based on specified input criteria with speci-
fied files of output generated. The parametric study plots can be generated
for summary data plotted against any parameter, such as Beaufort number, and
classified into five subgroups based on a parameter such as ship speed or
relative wave direction. In addition to the parametric plots, tabulations
may also be generated. Spectra computations can be conducted using the
unfiltered digitized transducer record . Figure B-5 summarizes the various
data–presentation formats discussed above. Samples of these formats, except
spectral analysis, are presented in the three SL–7 seasonal reports,
References (8) , (9) and (10)
Teledyne is currently under contract to the United States Coast Guard to
maintain the SL-7 data base. This contract is strictly a maintenance con–
tract with very limited funds for additional data analysis. When assessing
the SEA-LAND McLEAN data base, inquiries should be addressed through the
Secretary of The Ship Structure Committee for approval before contacting
Teledyne Engineering Services, Inc.
At this point, it would be appropriate to discuss the full scale SL-7 data
that has not been reduced. The majority of the strain information has not
been examined in any detail. In fact , the majority of the strain data is
still in the analog form as recorded (see Table B–1) . This unreduced strain
data includes:
(a) The
and
(b) The
the
(c) The
longitudinal vertical bending stress amidship from individual port
starboard strain gauges.
strain data obtained by “run bys” at several hatch corners to obtainstress distribution at the respective locations.
strain information taken at several tra”s”erse box girders a“d
longitudinal box girder intersections. These data were recorded so
that the longitudinal warping restraint could be inferred at the transi-
tion from open hatch to closed section at the forward deck house and the
“S” bending due to torsional loads experienced by the ship.
(d) Quarter point shear and torsional shear.
B–19
The demand for these data by the design and construction community has beenminimal to non-existent even from researchers who originally requested the
data. Therefore, the recommendations for further data analyses should be
viewed in that light. Although these data are design specific and represent
the SL-7 containership design, the data may also be applicable to open–decked
containerships in general. Torsional effects on the containership’ s hull
are of particular interest to containership designers.
ABS did analyze data obtained from several locations as part of the valida-
tion of the DAISY finite-element computer program. The comparisons involved
the prediction of wave-induced stresses and was based on the wave data re-
corded on board the SEA-LAND McLEAN. Any correlations of any of the data
obtained from the SEA-LAND McLEAN instrumentation with the measured wave data
would not be well founded.
Many types of data analysis are possible other than those that would involve
the measured wave data directly. The log book information contains observed
wave height, sea state and wind speed information that may provide a basis
for categorizing the data, etc. The lack of wave data for comparative pur-
poses is a major setback; however, semi-quantitative analysis could be con-
ducted based on Beaufort number, etc. Examples of further data analysis could
include:
(1)
(2)
(3)
(4)
Analysis of the instantaneous distributions of wave-induced stresses ob-
tained from the “rub-bys” around hatch corners for various heading and
wave height groups. This would yield information on the distribution of
stresses about the hatch corners that result from torsional
bending, etc. This could also be done for the gauge locations at trans-
verse girders to investigate the effects of torsion.
Development of long–term statistical distributions of wave-induced stress
obtained from amid ship vertical bending and hatch corners, etc. The long-
term statistical distributions would be developed on the same basis (i.e.
Beaufort number, etc. ), and may provide insight into the effects of stress
concentrations, etc. , on existing load criteria. This could also be con-ducted for various headings to isolate torsional effects, etc.
Several studies indicate that additional data reduction of the high-
frequency wave-induced stresses is required. This information would beuseful for future load-criteria examination, if deemed necessary by SSC.The exact type of data reduction needed depends on the intended use.
A minimum data reduction would include the RMS and number of cycles foreach interval of data for the high-frequency wave-induced stresses.
The SSC has shown interest in the SEA–LAND McLEAN data base for the
determination of strain rates. It must be remembered that the wave-induced strain rates experienced by the SEA-LAND McLEAN would be higherin head seas and lower in following seas than is typical d“e to the highspeed capabilities of the SEA–LAND McLEAN. The strain data recordedaboard the SEA-LAND McLEAN results from several types of loading sources .These sources may be identified and strain rates determined accordingly.Howe”er, additional data reduction may be required to conduct the analysis,
B-20
(5)
especially in regard to the high-frequency wave-induced stresses .Additional consideration should also be given to the definition of‘typical’ strain rate for the SEA-LAND McLEAN. Does typical refer to
average for the existing data (three seasons) or average expected for
the sEA-LAND McLSAN ? These are the types of questions that need to
be answered before the applicability of the SEA-LAND McLEAN may be
determined.
The data recorded at the forward hatch corner where radial cracks
were observed would provide a data base for future fatigue analysis
programs. However, these data are still in analog form, as recorded,and has not been analyzed in a useable form for fatigue analysis.
B-21
SHIP STRUCTURECOMMITTEESL-7 REPORTSTO DATE
SL-7-1, (SSC-238 ) - Design wd Installation of 4 ~~P R=p~.e In8*~~t@~on %8tem A~~d the
SL-? CLas6 Containership S. S. SEA-LAND McLEAN by R. A. Fa~n. 1974. AO 780090.SL-7-2,(SSC-239)- WaveLOCI&ina modelof thesL-7c@aizePehip~~iw at oblq~ ‘diwe
in Regular Waves by J. F. Dalzell and M. J. Chlocco.1974. AD 780065.SL-7 -3, ( SSC-243 ) - Structural Ana2yei8 of SL- 7 Contuinership LITI&? Combined Loading of Vertical,
Iateraland TorsiorulMoment. Using Finite Element Techniques by A. M. Elbdtout4,0. Liu, and H. Y. Jan. 1974, AO-AO02620.
SL-7-4, (SSC-246) - Theoretical Estimates of VnueLoadson the SL-7 Containership in Regularand Irregular Seas by P. Kaplan,T. P. Sargent,andJ. Cilmi. 1974. AO-N0455’4.
SL-7-5,(SSC-257)- SL-7 Instrumentation program Eiwkgiwumi and Re8earch Plan by H. J. Siekierka,R. A. Johnson, and COR C. S. Loosmore, USCG. 1976. AO-A021337.
SL-7-6, (SSC-259) - Verification of the Rigid Vinyl Modeling Techniques: The SL- 7 structureby J. L. Rodd. 1976. AO-A025717.
SL-7-7, (SSC-263) - Static Structural Calibration of shipRe8pon8e Instrwnentation System Aboardthe SEA-LA.VD MCLEA.V by R. R. Boentgen and J. U. Wheaton. 1976. AO-A031527.
SL-7-8, (SSC-264) - First Season Results frm Ship Re8p0n8e Instrumentation Akzrd the SL-7Cla8s Contaixership S. S. SEA-LAND McLEAN in Ahth Atlantic Service by R. R. 8oentg en,R. A. Fain, and J. W. IJheaton. 1976. Ao-A039752.
SL-7-9, Second Season Re8ults fromShipRe8pon8e I“ntrwnentczti.m Aboard the SL-7 Claes Contai?ter-ship S. S. SEA-LAND McLEAN in No?th Atlantic Service by J. U. Uheaton and R. R. 8oentgen.1976. AO-A034162.
SL-7-10, Thi?d Season .Qewlta from Ship Re.sporwe Instrumentation Abocrd the SL - 7 Crass Container-ship S. S. SEA-LAND McLEAN in North Atlantic semi.. by R. R. Boentgen. 1976. AO-A034175.
SL-7-11, ~SSC-269) - structural Tests of SL-7 Ship Mode2 by W. C. Webster and H. G. Payer. 1977.AO-A047117.
SL-7-12,(SSC-271) - A Cozv.elation Stzudy of SL-7 Containers hip Loads and Motions - Model Tests andCompute?’ Simulation by P. Kaplan, T. P, Sargent, and M. Silbert, 1977. AD-A049349.
SL-7-13, A Report on Shipboard Wa.eheight Radar S$st.m by O. Chen and O. Hammond. 1978.AO-A053379.
SL-7-14, (S SC-277 ) - Cri@rzal Radar ad Standard l)tcke? Wavemeter SL - 7 Containaship Data Re&ction
arid Correlation Sample by J. F. Oalzell 1978. AO-A062394.SL-7-15, (SSC-278) - Wauemeter Data Reduction Method and Initial CQti for the SL-7 Co.tui~Fehip
by J. F. Oalzell 1978. AD. AOtSZ3gI,SL-7-16, Radar and Tucke, Wawmete, Data fromS, S. SEA-LAND McLEAN - Voyage 32
by J. F. Oalzell. 1978. AO-A057154.SL-7-17, Radar and Tucker Wauwwte? Data fmm S. S. SEA-L4ND McLEAN - Vo3age 33
by J. F. Oalzell. 1978. AO-A057155.SL-7-18, R& d tic~, v=wmetep Data f,O.s. s. 5SA-LAND MCLEAN - vOYage 34
by J. F. Dalzell. 1978. AO-A057155.SL-7-19, Radar and Tucker Wavemeter DcTta r.om S. S. SEA -LAND MoLEAN - Voyages 35 and 36E
by J. F. Oalzell. 1978, {AO-AO 7157.SL-7-20, ( SSC-279 ) - ModifiedRacim. and Stan&rd licker Wauemete? SL- 7 Contnine,ship Data
by J. F. Oalzell. 1978. AO-A062393,SL-7-21 , &&r and TwkeF Wavemete, Dot.AoAor@#. s. ssA-LAND McLEAN - Voyage 60
by J. F. Oalzell. 1978.SL-7-22, Raiar & Tucker Wauem?t.e, Dato f?cwS. S, SEA-LAND McLEAN . Vo$age 61
by J. F. Oalzell. 1978. AO-A057005,SL-7-23, (SSC-280) - Results and Eoaluatwn of the SL-7 Containe?ship Radar and Tueke?
Wazwnet.? Data by J. F. Oalzell 1978. AO-A062392.SL-7-24, (SSC-282) - Compari&%! of Strew8e8 Calculated using the DAISY Swtem to Those
Meoou?.ed on the s>7 Containemhip Progrw by H-Y Jan, K-T Chang, andM, E, !Jo”narowski 1979. AC!-A069031.
~SL-7-25, (SSC-286 - Reeulte of the First Five “Dot. Yea?%” of E.TtFeme Stwes Scnztch
Gauge Data Colzect.d Aboard SEA-LAND’s SL-7’8 by R. A. Fain and E. T. 8ooth.1979. AC!-A072945.
SL-7-26, (SSC-304 - SL-7 Eztreme Strene Data Co7-Leotion and Re&ctior! by E. T. Booth. 1981.
ISL-7-27, (SSC-311 - Evaluation of s,!-7 Scratch-Ca~e Data by J. C. Oliver. 1981.SL-7-28, (SSC-313 - SL-7 Rewarch Frcgrmn .%mnary, Conclusions and Recm?mwndntions by
K. A. Stmbaughand W. A. Wood. 1981.
.
SHIP RESEARCH COMMITTEEMaritime Transportation Research Board
National Academy of Sciences - National Research Council
The SHIP RESEARCH COMMITTEE has technical cognizance of theinteragency Ship Structure Consnittee’sresearch program.
Mr. A. D. Haff, Chainnan, ConsuZtmt,ArvzapoZis,MDProf. A. H.-S. Ang, Civil Engrg. Dept.,Ltniverei@of I’llirwle,Champaign, ILDr. K. A, B1enkarn, Researchtirecto~,OffehoreTeohnoZcgy,AmccoProduction
Company,TuZsa, OKMr. D. Price, Sr. Systems AnaZyet,National Oceanic and AbnosphericAc3nini-
etraticn,Rockvihe, MDMr. D. A. Sarno, Manager-Mechanice, ARYCO Inc.,MiddZetcwn,OHProf. H. E. Sheets, Dir. of .Wgineer+ag,AnaZyeis& TechnoZcgy,Inc.,
Ston<ngton,CTMr. J. E. Steele, NavalA~chitect,Quakertcw,PAMr. R. W. Rumke, Executive Secretary, Ship ReeearchCommittee
The SHIP DESIGN, RESPONSE, AND LOADprepared the project prospectus and evaluatedproject.
CRITERIA ADVISORY GROUPthe proposals for this
Mr. J. E. Steele, Chainnan, NavaZ Architect,Quakertowz,PAMr. J. W. Boylston, Consulting Naval Arch<tect,Giannotti.3Ae80ciatee,Inc.,
Annapo1i8,MDProf. R. G. Davis, Aeebtant Profee80rof hkzvaZArc?a<tecture,Dept.of
MarineSngqT.,TexasA&M University,Galveston,TXMr. P. W. Marshal1, Civil Engineering Advieor,ShelZOil Company,
Houston,TXProf. R. P1unkett, Dept.of Aezwepace.lihg~.and Mecti{cs, Universi@jof
M$nneeota,MinneQpOzi8,WMr. C. B. Walburn, Aeei8tcmt?7avaZArchitect,BethZehemSteel,Corp.,
Matine~v<8<cm, spm?70w8 Point,MD
The SR-1279 ad hoc PROJECT ADVISORY COMMITTEE provided the1iaison technical guidance, and reviewed the project reports with theinvestigator.
Mr. J. E.Mr. A. D.Mr. P. M.Mr. A. C.Dr. W. R.
Steele, Chainnan, ilavaZArchitectjQuakertcwn,PAHaff, Consultant;Annapozis,MDKimon, EXXONInternat<onaZCo.,Fbzbn Park,NJMcC1Ure, AZcm C. McChre Aeeociate8,Inc.,Houeton,TXPorter, V.P. for AcademicAffdP8, State Univer8i@ of NW York,
MaritimeCoZleg8,Bronx,NY
SHIP STRUCTURE COMMITTEE PUBLICATIONS
SSC-300,
SSC-301,
SSC-302,
SSC-303,
SSC-304,
SSC-305,
SSC-306,
SSC-307,
SSC-308,
SSC-309,
SSC-31O,
SSC-311,
SSC-312,
SSC-313,
These docwnentsare distributedby the NationalTechnicalInfozwationService,Springfield,VA 22314. Thesedocu-ments have been announcedin the ClearinghouseJournalU. S. GovernmentResearch& DeveZopmentReports (USGRDR)under the indicatedAD numbers.
Smary of NondestructiveInspectionStandardsfor HeavySectionCastings,Fo~ings, and WeZdmentsby R. A. YOUS haw. 1980. AD-A099119.
ProbabilisticStructuralAnalysis of Ship Hull LongitudinalStrengthby J. C. Daidola and N. S. Basar. 1981. AD-A099118.
Compute~AidedPreliminaryShip StructuralDesign by A. E. Marsow
and A. Thayambal 1 i. 1981. AD-A09911 3.
Fatigueand FractureToughnessCharacterizationof SAW and S/44A537CLassI Ship SteeZ WeZdments by J. F, Souak, J. W. Caldwel 1, andA. K. Shoemaker. 1981.
SL-7 ExtremeStressData Collectionand Reductionby E. T. Booth. 1981.
Investigationof Stee2s for ImprovedWeZdizbiZity in Ship Construction-Phase 11 by B. G. Reisdorf and W. F. Domis. 1981.
Ezperi?nentalProgramfor the Determinationof Hull StructuralDampingCoefficientsby P. Y. Chang and T. P. Carroll. 1981.
Evaluation of FractureCz+teriafor Ship Steelscmd WeldmentsbyA. W. Pense. 1981.
Critertzfor HuZ2-Machine~RigidityCompatibiliQ by W. 1. H. Budd,S. V. Karve, J. G. de Oliveira, and P. C. Xirouchakis. 1981.
A RationalBasisfor the Selectionof Ice StrengtheningCriteriaforShZps - VOL. I by J. L. Coburn, F. W. DeBord, J. B. Montgomery,A. M. Nawwar, and K. E. Dane. 1981.
A RationalBasisfor the Selectionof Ice StrengtheningCritefiaforShips - V02. II - Appendicesby J. L. Coburn, F. W. DeBord, J. B.Montgomery, A. M. Nawwar, and K. E. Dane. 1981.
Evaluatwn of SL-7 Scratch-GaugeData by J. C. 01 iver. 1981.
Investigationof InternsZ Corrosionand Corwsion- Contro1 Alternativesin ConmerciaZ Tankskipsby L. C. Herring, Jr. and A. N. Titcomb. 1981.
SL-7 ResearchProgramSunmary,Conclusionsand RecorinnendationsbyK. A. Stambaugh and W. A. Wood. 1981.