modularity: maximizing the return on the navy's investment

JOHN T. DREWRY & OTTO P. JONS

MODULARITY: MAXZMZZZNG THE RETURN ON T H E

NAVY’S INVESTMENT

THE AUTHORS

Mr. John T. Drewry was educated at the University of Michigan f rom which he received his BSE degree in Naval Architecture and Marine Engineering, at Massachusetts Institute of Teclinology from which he graduated with his Masters degree in Naval Archi- tecture and Marine Engineering, and at The George Washington University Night School where he is currently worlcing on his Masters degree in Business Administration. A commissioned oflicer in the U S . Navy, he was stationed at NSRDC during his period of active duty, completing this service with the rank of Lieutenant. From 1968 to 1972 he was employed a t Litton Ship Systems, Inc . , Los Angeles, Calif. , as the Department Manager of Ship System Engineering and Project Engineering, DD-963 Program. Since 1972 he has been with the NAVSEC Design Division and has held various positions including those of Chief, High Performance Ship Design Section; Design Man- ager for DG/AEGIS Conceptual Design; Design Man- ager for Modular Ship Design Projects; and currently as Deputy Design Manager for Advanced Submarine Projects.

Mr. Otto P. dons began his career in the field of Naval Architecture and Marine Engineering with the degree of Dip1.-lng. from the University of Hamburg/ Technical University of Hanover, followed by a Master of Science degree which he received from Massa- chusetts Institute of Technology. In 1967, he joined the Advanced Marine Technology Division, Litton In- dustries, where he was employed as a Senior Naval Architect; Section Manager-Hull Structural Design; and Manager-Ship Systems Engineering Department, LHA Program Once. In 1974, he joined HYDRO- NAUTICS, Inc . , Laurel, Md., where he was the Principal Research Scientist and Head of the S h i p Systems Design Division until he assumed his present position as Director of the Washington Ofice, De- signers & Planners, Inc., a subsidiary of the Todd Ship yards Corporation.

ABSTRACT

Much has been said about “modularity.” Various schemes have been proposed. Advantages and disadvantages have been discussed. For many, the question of its ultimate worth to the Navy is still unanswered. A methodical and systematic evaluation of the ultimate worth of modularity appears to be warranted. The question of “worth” will be addressed in terms of: “What can modularity do to improve the Navy’s return-on-investment ?” The issue “return” will be dissected into its elements and sub-elements.

This paper will answer the question of overall worth of modularity when applied to naval ships and demon- strate that modularity can reconcile the conflict between “Design-to-Cost” and “Design-to-Change”. It will be shown that modularity is indeed very worthwhile, if not the most promising concept of providing the most defense for a severely constrained budget.

INTRODUCTION

WHAT IS THE PROBLEM?

I T Is GENERALLY AGREED THAT T H E NAVY has an in- dispensable role to play in defending the nation. It is not clear, however, that there is sufficient appreciation for the fact that the NAVY is faced with the serious problem of not being able to fully perform its missions.

The NAVY’S mission always has included the control of the sea, with surface combatants and ocean escorts carrying the main load. Figure 1 shows how force levels have reached a new low whereas the threat has continued to increase. In the last decade the NAVY’S share of this nation’s defense load has been consider- ably increased by adding the vital mission of sea- based strategic deterrence in the form of ballistic missile submarines. This added responsibility made it necessary to allocate an increasing percentage of Ship

198 Naval Enpineen Journal. April 1975

DREWRY/JONS MODULARITY

70

6 0

PRESENT \PROJECTED 400 I I I

I

Figure 1. Decreasing Force Level and Increasing Threat.

Construction, NAVY (SCN) appropriations to the construction of submarines (Figure 2 ) . In return, the SCN budget has nominally been increasing; it has, at best, remained constant in terms of real dollars (Figure 3). Considering the ever increasing sophisti- cation of hardware and software required to counter today’s threats effectively, the gap between what is needed and what is available continues to widen.

The request for an increased defense budget to relieve the problem i s becoming increasingly unpopular

I-

0 S U B M A R I N E S +

I- A

50

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Figure 3. SCN Budget in Sominal and Real Dollars.

as the result of growing demands in other areas of na- tional concern. Trying to resolve these conflicting requirements would go obviously beyond the scope of this paper. I t would require an answer to the question of what we can afford to spend in each area.

A measure, however, exists which combines the issue of need with that of affordability; it simply converts the controversial clamour of “more dollars for defense” to the generally accepted goal of “more

0 S U R F A C E C O M B A T . 6 O C E A N E S C O R T S ( S C 6 O E )

A O T H E R S H I P S

A

0

0 1 1 I I I 1 I I I = , 1 9 6 5 1 9 6 6 1 9 6 7 1 9 6 8 1 9 6 9 1 9 7 0 1 9 7 1 1 9 7 2 1 9 7 3

Figure 2. SCN Budget Share vs Ship Types.

Naval Enpinoan Journal, April 1975 199

MODULARITY DREWRY/JONS

defense for the dollar.” This measure is “Return-On- Investment (ROI) .” ROI consciousness has been identified as a key to a more effective utilization of the investment in research and development [ 11.

This paper is intended to present means for maximizing the NAVY’S “Return-On-Investment.’’ This requires us first to define the term, and then to define the specific detailed objectives which if attained will constitute positive steps towards attaining the overall objective of maximizing the “Return-On-Investment.’’ The paper then offers the concept of modularity a s a most promising means of achieving this goal. Prevail- ing misconceptions of the concept of modularity neces- sitate the definition of the concept as it is viewed by the Authors. The specific features of modularity can then be correlated with the detailed objectives to be attained if the NAVY’S “Return-On-Investment” is indeed to be maximized.

THE NAVY’S RETURN-ON-INVESTMENT

The term “investment”, in this context, can be de- fined as that portion of the defense budget that is spent on our naval forces. Its primary elements, to the extent that they are pertinent to our discussions, are: a ) Ship Construction, NAVY (SCN), b ) Weapon Pro- curement, NAVY (WPN) , c ) Other Procurement, NAVY (OPN), d ) Research, Development, Test and Evalu- ation, NAVY (RDT&EN), and e) Operation and Main- tenance, Navy (O&MN).

The term “return” shall be synonymous with the military strength of our naval forces a s given by quantity (number of ships) and deployable capability (quality). As such, quality has two components: a) operational effectiveness and/or capability, and b) operational availability. Availability combines the elements of reliability (Mean-Time Between Failures- MTBF), maintainability (Mean-Time to Repair- MTTR), and the fraction of the ship’s lifetime lost due to overhaul, modernization, and conversion.

Capability of a weapon system is often seen in absolute terms such as fire power and/or lethality, range, reaction time, and so forth. The mistake is repeatedly made to confine the assessment to just these absolute values. More important is capability relative to that of a potential adversary; it adds the factor time to the value assessment of weapons. Time, in turn, involves the element of change since the adversary may 1) develop newer, better weapons and/or 2) develop weapons which a re sufficiently different to negate existing defensive measures.

These simple facts establish a fundamental rela- tionship between military value of a weapon system and time. They define the threshold of diminishing military value, or obsolescence a s shown in Figure 4.

It may be very difficult to determine the exact time at which a weapon becomes obsolete. However, it will occur more rapidly a s the pace of technological evolution quickens, and as more advanced technology is available to a potential adversary. In the recent past, the technology life span of weapon systems has been

\ >-I-

DiYiLOP*tMl T I M E - , _ U 5 C f U L L l F i

Figure 4. Military Effectivenes of Weapon Systems as a Function of Time.

ten to twenty years, leaving an operational Iife of five to ten years after subtracting five to ten years for development and production. I t is, of course, the state of the technology a t the time of initiation of development, not a t the time of delivery, which is reflected in the product. Thus time emerges a s one of the crucial factors determining the quality of naval ships and, thereby, “Return-On-Investment.” I t is not only a basic ingredient of operational availability, but it may have an even greater influence on operational effectiveness.

DETAILED OBJECTIVES

Maximizing the NAVY’S “Return-On-Investment” has been identified as requiring maximizing quantity and quality of naval ships within the constraints of an essentially fixed overall budget. The detailed objectives necessary to satisfy this overall goal will now be identified.

Increasing Quantity of Ships

Assuming that the NAVY’S share of the defense budget will remain generally constant, the only two ways of increasing the quantity of ships are: a ) cost savings and reallocation af these savings to the budget element (s) which contribute directly to increasing force levels, and b) increasing the life of naval ships by improved longevity.

Earlier, five major budget elements were identified. excluding the element for military personnel, which account for most of the NAVY’S budget. Of these, the SCN category contains funds for new construction and modernization,’conversion. I t is this category that de- termines how many new ships enter the Fleet and how many existing ships a re retained through modernization and conversion. Therefore, given a fixed total budget, the detailed objectives that would contribute more ships to the NAVY’S Fleet a r e as follows:

1 ) Shift funds to SCN from other NAVY budget cate-

200 Navel Enpineerr Journal, April I975

DREWRY / JONS MODULARITY

gories by realizing savings in these latter categories.

2) Reduce the cost of modernization and conversion to free more funds for new construction (or for more frequent modernization).

3) Reduce the cost of new construction to allow construction of more ships (or more capable ships).

4 ) Increase ship platform longevity.

Increasing Effectiveness of Naval Ships

Time is the key parameter used to establish availability. However, it has also been shown to be crucial to operational effectiveness since the Military Worth- Decay Curve (Figure 4 ) is a function of time. It is evident from this Figure that anything which increases the shaded area under the Decay Curve will result in improved operational effectiveness. Alternatives for achieving this lie in either raising the curve or by earlier application of technology as the result of reduced development time. Raising the curve can be achieved three alternative ways: a ) by increasing the absolute capability or performance of the weapon system, b) by accelerating the advancement of the state-of-the-art through increased emphasis on RDT&E, and c) by more frequent modernization; at a reduced scope, however, by limiting the modernization to crucial system components with the shortest technological lifespan rather than exchanging entire systems. Alternative a) involves defense needs to counter new threats, and alternative b) requires policy decisions at the DOD level. As such, they are beyond the scope of this paper. This leaves alternative c ) as the only alternative to be considered here.

Another way of increasing operational effectiveness is by extending the shaded area under the Military Worth-Decay Curve (Figure 4) to the left (back in time). This can be done by reducing the development time of naval ships, thereby increasing operational effectiveness and capability by means of accelerated implementation of new technology. The current approach to naval ship development consists of two activities, which take place in series: a ) the development of the weapons suit and/or the combat systems, and b) the development of the ship platform (hull, propulsion and various support systems), including the integration of the combat system into the platform.

This series development is shown in Figure 5, which has been excerpted from OPNAV’s Surface Warfare Plan. It is noteworthy that it takes approximately 14 years from initiation of development of a combat system to its introduction into the Fleet. Construction of a series of ships in one class results in further loss of military worth and effectiveness (Figure 6 ) .

Alternatives for reducing the long ship system development period and thereby improving operational effectiveness are: a ) reduced combat system development time, b) reduced ship platform development time, and c) parallel development of combat system and

platform. A condition comparable to the development cases

discussed above arises during conversion and modernization. In each case the time required to develop the combat system which replaces the old system and the time required for the refit process is associated with the worth-decay phenomenon. Shortening these time spans means improved military effectiveness.

Iniproring Operational Availability

Improving operational availability implies reducing the amount of time a ship is either not available or only partially capable to perform its intended mission. Figure 7 shows a tqpical operational profile of a naval ship assuming a prime operational lifetime of 25 years. It is based on four regular overhaul periods. each of six months’ duration. and one modernization and one conversion requiring on the order of twenty months each. Whereas one might argue about the individual time durations above, it is generally accepted that an “off-line” time at least of twenty percent-as resulting from the abo\-e---must be expected 13). For the remainder of time. however. the ship is still only partially available as the result of reliability (MTBF) and repair (MTTR) problems. Whereas the reliability problem of complex electronic combat system elements in particular has been widely publicized, it is generally less well known that the actual repair time is generally only a small fraction of the total time required to correct a casualty. A study was conducted by SMITH [41 on twenty ships selected at random. 6n a period of 60 days they incurred a total of 101 casual- ties (CASREPS) requiring a total of 298 repair parts. The results of this study showed that only 14 of these parts. less than 5C:. were actually onboard. thereby leading to an average time required to correct each casualty of over h e days. The average availability of about 85C; assumed in Figure 7, again, is considered realistic, if not optimistic.

In order to improve “Return-On-Investment” by improving operational availability, the following detailed objectives are established:

1) Decreasing the time required for modernization and conversion.

2) Decreasing the time for regular overhauls and restricted availability (ROH and RAV).

3) Increasing component reliability. 4 ) Increasing component and system maintain-

ability.

These objectives and those derived in the foregoing cover a very broad range, with an underlying theme being that change in modern naval systems is a virtual certainty. “Design-for-Change” should therefore be recognized as a necessity. In our opinion, the concept of modularity stands in many ways for “Design-for- Change,” as substantiated in the Sections of this paper that follow.

Naval En9ine.n Journal. April 1975 201

C O N C E P T F O R H U L K T I O N

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202 Naval Engineers Journal, April 1975


- SHIP

~

HOD/ R O H H O D ROH C O N V ROH ROH * + * + *

I

- . - P R I M E O P E R A T I O N A L L I F E

Figure 7. Operational Availability Profile of Modern Combatants.

WHAT Is MODULARITY?

General Definition

Not everyone has the same understanding of the meaning of modularity. In fact, the word lacks pre- cision and is open to many varying interpretations. The Dictionary [5] contains its own array of various definitions for module: 1) a standard, 2) a uniform component used repeatedly in erection or construction, and 3) a self-contained assembly of components that perform a specific class of tasks in support of the major function of the primary object.

Unfortunately, the most common error is to define modularity too narrowly-to say that modularity is containerization, for instance. Containerization is, however, a very narrow band within the broad modularity spectrum. Therefore, the following very broad definition of modularity will be adhered to in this paper :

Modularity is the physical and/or functional grouping of elements of a complex system into buildings blocks for the purpose of (1) ease of construction, (2) ease of integration. (3) ease of installation, (4 ) ease of removal. and (5) ease of interchangeability.

The Many Facets of Modularity

When most people consider modularity, they think only of prepackaged units that are dropped on board a transport vehicle, used for a time, and then removed (perhaps replaced by another module). Their focus is confined to the module, and if asked to de- scribe modularity, they would talk only about group ing a number of related things, pre-assembling them in a common container such that it is easily movable from here to there, and “taken off and dropped on” with relative ease. The point is that this view sees only onethird of the whole concept of modularity.

Any design solution that employs the concept of modularity must give full consideration, not only to the module, but also to the transporting platform and to the interfaces between the module and platform. The left side of Figure 8 illustrates this point. In each of these areas of consideration, there are many different ways in which to implement the concept, as shown on the right side of Figure 8. These various means of implementation are referred to as “features” of the modularity concept. It should now be very clear from Figure 8 that containerization, for example, is quite a small part of modularity. In fact, it is no more than an alternative physical configuration of module

Naval Enqinwn Journal, April 1975 203

MODULARITY DREWRY/ JONS

P r e p a c k a g i n g

INTERFACES +o S t a n d a r d i z a t i o n

puTFf3 S t d . G r i d P a t t e r n s

Figure 8. Modularity Features.

prepackaging. By identifying the variety of features in Figure 8, the intent is not to propose using all features all the time, ,but rather to propose judicious selection of that combination of features that maxi- mize the benefits derived under the constraints at hand. Thus it will be worthwhile, at this point, to examine more closely the three areas of consideration that comprise the modularity concept.

The Module

Figure 9 illustrates the various ways of pre-packing : the container, the pallet, and other structured and un- structured modules, sub-assemblies, etc.

The building block approach, also shown in Figure 9, is an extension of the pre-packaged module; it allows enhancement of capability through the simple exchange, addition or deletion of a module to the basic configuration already installed. The basic configuration can be standardized for all ships in the Fleet, and for the ships with more demanding missions supple- mentary module(s) can be added. Furthermore, this approach has the potential of allowing modernization and conversion at the component level instead of the system level, given that the modernization involves simple addition or reduction to capability that already exists. Various attempts at building block design are now being pursued, such as the Naval Electronic Sys- tems Command (NAVELEX) projects “Automation Afloat” for automatic message processing distribution and the “Design-to-Price’’ Electronic Warfare (EW) System.

S h i p p i n g / U n s h f p p . Open’g.

Another kind of module is the standardized basic component as shown in Figure 9 and exemplified by the circuit card of the NAVELEX Standard Hardware Program [S] . This approach requires careful consideration during system design of functions and means of executing functions that are most likely to change due to advancing technology or threat changes. Those functions most subject to change are then allocated to modular components that can be replaced with relative ease. But flexibility to change is not the only advantage-ease of maintenance, reduced acquisition cost, and improved availability are also possible. If the component module is so basic as to be common to many applications, it can be standardized and bought in large quantities at lower unit costs. Further- more, if the unit cost is low enough, a failed module can be discarded to save labor costs. In any case, the failed module can be readily replaced and removed for off-site maintenance.

Interface Between Module and Platform

It is self-evident that efficiency in installation, removal and exchange of modules is a strong function of the nature of interfaces between modules and the platform. The simpler the interface, the more efficient the exchange will be. Modularity is not, however, limited to one way of achieving simplicity of interface. There are numerous ways to achieve this: a ) by interface buffering and use of adapters: b) by standardization ; c) by consolidation ; and d ) by complete elimination.

204 Naval Enqineerr Journal, April 1975


B U I L D I N G BLOCK M O D U L A R I T Y

S T A N 0 A R 0 H A R 0 W A R E C I R C U I T B O A R D

C O N T A I N E R I Z A T I O N ( D E T A C H E D )

C

C O N S T R U C T I O N M O D U L A R I T Y ( M A J O R S U B A S S E M B L I E S )

: O N T A I N E R I Z A T I O N ( I N T E G R A T E D )

W E A P O N P R E P A C K A G I N G

Figure 9. Random Examples of Modularity.

Interface buffering and use of adapters could be viewed as the brute force treatment. Here, no attempt is made to coordinate module to platform or even fnodule-to-module interfaces. Instead, an intermediate piece of equipment is designed to adapt the module to conform to the platform, such as an adapter foun- dation for different weapons. This approach is currently being tested by BLOHM and Voss of Germany [ 71. Data and frequency converters, transformers, rectifiers, pressure reducers, and quality regulators are other examples of interface buffers. Obviously this method is costly in terms of the adapters themselves as well as their installation, but in order to continue to utilize existing systems, designed prior to initiation of a more disciplined approach to modularity, the use of interface adapters will be a viable option.

For new systems, standardized interfaces make a great deal of sense. For modularity to be effected, standardized module-to-platform interfaces would certainly simplify exchange of one module for another. Even without regard to modularity, standardized interfaces simplify equipment-to-equipment integration and eliminate the need for adapters, converters, and so forth. It is noted that the NAVY has already embarked on an extensive interface standardization program [ 81.

Consolidation of interfaces reduces the number that must be buffered or standardized. The concept that best exemplifies this is multiplexing. Present methods of distributing and processing data involve many cables of different types, as well as switchboards and signal conversion equipments. And, of course, each

cable has its own interconnection interfaces between equipments. Multiplexing involves transformation of all signals, analog data, and digital data into multi- plexed digital signals, and then distribution of these signals on a time or frequency division basi-ne cable thus takes the place of many.

Finally, complete elimination of interfaces is the ultimate in interface simplification. Consider, for example, an electronic system modularized with its own self-contained power supply or air conditioning unit. Clearly, installation/removal of such a module would be relatively easy, although a disadvantage would be the added cost of the self-contained services.

DR. C. E. BERCMAN. Technical Director of the Naval Electronic Laboratory Center (NELC) in San Diego, has suggested a method to eliminate and consolidate many of the data and signal interfaces between sensor/weapon groups and the ship’s command and control system. Presently, the latter is centralized and highly integrated, performing all of the processing of raw data from the terminal groups. Considering the advances in integrated circuits and miscroprocessors, and the attendant reduced costs of such hardware, DR. BERCMAN proposes that much of the data processing be performed by user equipment, thus eliminating the need for transferring this data to a central processing unit. The most significant advantage of this concept. referred to as “Direct Functional Mechanization (DFM),” would be minimal need for software repro- gramming when system changes are made [9].

Naval Enginwn Journal, April I975 205

DREWRY/ JONS MODULARITY

The Platform.

The platform of modularity is necessary for the containment, installation, removal and interchange of modules. The design budget approach has had its greatest application on the NAVY’S DD-963 where weight, space and service reservations were designed into the basic ship for planned modernization and conversion. Such reservations avoid major structural modifications and changes to centralized service gen- eration systems, while a disadvantage is the cost of the extra space provided.

Simply providing space margins for future systems in not sufficient if the platform is to be truly adapt- able to change; the configuration of space provided is important. In this regard a direct correlation between the space dimensions and the dimensions of standardized module sizes has obvious advantages. This leads to the standard grid concept where space dimensions are multiples of a standard unit derived from a standard sized module. Also, a means of trunking services to the module areas is desirable, and provisions for module shipping and unshipping routes must be carefully designed.

The value of modularity rests heavily on being able to avoid costly and time-consuming rip-out and re- installation of cabling, piping, and ducting. Such avoidance by necessity requires that the platform provide centralized distribution centers in the areas where modules are to be arranged. Thus, the only distributive services hardware prone to change would be that which interconnects the module with the distribution center. Of course, the benefits of modularity are not free-the cable, pipes and ducts trunked to the distribution centers will no doubt be larger than normal for the base ship in order to accommodate possibly increased demands for future systems.

Clear access to platform areas in which modules are arranged is equally important. Time and cost savings are very much dependent on clear shipping and unshipping routes. Removal and installation of modules should have little if any effect on surrounding struc- ture. Furthermore, direct vertical movement of modules fs more easily achieved than lateral movement. For these reasons, directly accessible topside locations are highly desirable. Fortunately, combat systems, which are most subject to change and therefore the best candidates for modularity, are generally located topside.

Modularity Facilitates Change

This section has endeavored to show that modularity is not subject to a narrow definition, but rather is a general concept with the objective of facilitating change. There are many ways in which this objective can be achieved, but whatever method is employed, balanced consideration must be given to the module- carrying platform, the interfaces between the module and platform, as well as to the module itself.

Since the objective of modularity is to facilitate change, it is clear that application of the concept is most promising where change is most likely to occur, and for this reason the combat system elements are the most likely candidates for application of modular concepts. In fact, there have been numerous, albeit sporadic, applications of one feature or another of modularity to various combat system elements [ lo] . A more concerted, systematic movement on a much broader front will be shown to be warranted in order to achieve the objectives necessary for maximizing ROI.

MODULARITY: MORE SHIPS

Shifting Funds to SCN

In today’s environment of overly constrained bud- gets, the problem of proposing a shift of funds from one category to another is that all categories are likely to be underfunded. Also, it may appear naive to discuss the possibility of shifting funds without addressing certain realities inherent in Congressional appropriations and bureaucratic rivalries. Nevertheless, it could conceivably happen. It appears, then, that the various features comprising the modularity concept could contribute to savings in the budget categories WPN. O&MN and possibly OPN which were previously mentioned in the earlier Section entitled “The NAVY’S Return-On-Investment.” In order to establish the sup- porting rationale, we recall two features of modularity involving the module itself, i.e.. the building block design and the standardized basic component. Both the core segment of a building-block design and the standardized basic component involve standardization for a broad range of aplications, not only between ships of the same class but between classes themselves. Such wide-scale standardization (definitely a feature of modularity but not limited to the application of the modularity concept) would allow the NAVY to make extensive multiple buys. One study [ll] showed that “an average unit savings of 8%-17% per category can be expected providing a minimum of five shipsets are purchased.” Inter-class standardization should bring even greater savings since far more than five shipsets would be involved. The broad range application, to combat systems of the building-block-design and standardized-basic-components features, should reduce required funding in the WPN category, and simi- lary in OPN expenditures, if these features of the modularity concept were to be extended to hull, m e chanical and electrical (HM&E) systems as well.

The modular standardized-basic-component has the potential of effecting savings in O&MN expenditures. Such savings would be reflected in reduced maintenance man-hours due to improved reliability and maintainability (R&M) stemming from the potential of being able to replace high-failure modular components with progressively improved components without otherwise impacting the basic system of which the component is part. The ultimate in reduced mainte-

206 Naval Engineers Journal, April 1975


nance workload is represented by the NAVELEX Standard Hardware Program [6], when a failed module is simply discarded and then replaced.

Shifting Funds to N e w Construction

Having garnered the greatest possible funding into the SCN budget, it is now desirable to funnel the vast majority of these funds into new construction. To accomplish this, the cost of modernizations and conversions must be reduced.

The necessity of modernizations and conversions will no doubt always be with us due to the nature of warfare and the inevitability of threat changes resulting in continual changes to combat systems. In fact. modernizations and conversions are crucial for reducing the rate of ship retirement. The associated costs comprise a significant part of the SCN budget (since 1953. modernization and conversion costs have amounted to 20-25% of the SCN budget).

To illustrate the sizable expenditures (expressed in FY74 dollars) involved in past modernizations and

the budget cost of a newly constructed PF. Figure 10 is presented to illustrate the extensive changes to the combat system that characterize a typical conversion. Clearly. the process of modernization and conversion is ripe for sizable cost savings.

A closer examination of the breakdown of costs for modernization and conversion reveals the following (based on a sample of 15 different ships involving ASW modernizations in some cases, AAW conversions in others, and NTDS modernizations in still others) :

PERCENT OF BASIC CATEGORY MODJCONV. CONSTRUCTION

Hull Modification 36 k 3.5 Ship Services Modification 32 -t 3.5 Combat System Rip-out

and Installatian 28 -t 4.8

These three categories are synonymous with the three areas of consideration when applying the modularity concept: modular platform features apply to hull modifications ; interface features apply to ship

conversions, TABLE 1 is presented. I t is noteworthy that each of the various cruiser conversions was more expensive than a newly constructed DD 963 Class ship, and each of the various DLG modernizations exceeded

services modifications; and the module itself applies to combat system rip-out and installation.

Each of the major modernizations and conversions listed in TABLE 1 involved refit a t the total system

TABLE 1

COST BREAKDOWN FOR PAST MODERNIZATION/CONVERSION PROGRAMS

SHIP CLASS

1. CLEYELAND (CLG-3)

2 . CLG 4a5

3. CLG-6

4. CLG 7a8

5. ALBANY (CLGlO-12 1

6. FORREST SHERMAN (DDG31-34 )

7. MITSCHER (DDG35a36)

8 . FORREST SHERMAN ( 8 s h i p s : DD933 e t . a l . 1

9. ALBANY (CG10

( 8 s h i p s : DLC6 10.' COONTZ

e t .al . 1

. l . LEAHY ( DLG 1 6-DLC 2 4 )

~~

YEAR COMMISS IONEI

1 9 4 5 ( l a u n c h e d

1945

1945

1944

1945/1946

1956-1959

1953

1956-1959

1 9 6 2 ( a s C G )

1959-1961

1962-1964

DURATION OF (M)ODEFtNIZATION OR (C)ONVERSION

1956-25 mo. ( C )

1957-40 mo.(C)

1957-35 mo. ( C 1

1957-29 mo.(C)

1959-47 m o . ( C )

1965-24 mo. ( C )

1966-32 mo. ( C )

1967-20 m o . ( M )

1967-30 mo.(M)

1967-14 mo.(M)

AVG. BASIC CONSTRUCTION

COST

42.4

48.4

47.2

37.9

80.1

21.8

20 .1

1 6 . 1

20.3

20.5

1 2 . 4

Y74 $ I N

AVG. CFE COST

75.6

47.7

41.3

36.5

119 * 5

21.7

22.2

5.0

26.7

22.9

19.9

ILL I O N S

AVC. OTHER COST

19 .8

16.2

16.0

17.3

21.4

15.4

28.1 ( E x t e n s i v e . Rehab.

12 .2 ( E x t e n s i v e

Rehab. )

25.3

23.5 ( E x t e n s i v e

Rehab. )

16.0 ( E x t e n s i v e

Rehab. )

~ ~~

.VG. TOTAL END COST

137.8

112.3

104.5

91.7

221.0

58.9

70.4

33.3

72.3

66.9

48.3

Naval Engin-n Journal. April I97S 207

MODULARITY DREWRY / JONS

TARTAR M I u u CYL I

U

O U T B O A R D P R O F I L E I A N 0 1 LT.

I A D A I X H T I

ROOM

W N C Y L I C O N T I O C

O U T B O A R D P R O F I L K

BEFORE-

Figure 10. USS Somers (DDG-34; formerly the DD-947) Before and After Conversion.

level by the addition of an entirely new weapon system and/or the substitution of one entire system for another. Very few, if any, components of the system to be removed were common to, and could be left in place for, the replacement system. This is even true for pre-planned modernizations, such as the substitu- tions of various weapon systems on the DD-963.

Modernization and conversion of weapon systems have had significant effects on the distributive systems that service the combat system, such as electric power, cooling and ventilation. This has been largely due to inadequate capacity installed to serve the greater needs of the new weapon system (for example, the DLG-6 and DLG16 electric plants), and due to a great vari- ance in interface characteristics between weapon systems.

Major structural modifications, in addition to changes to arrangement of non-structural bulkheads and partitions, have characterized past modernizations and conversions. This has been due to lack of initial space and arrangement provisions for weapon system changes. Partial steps are now being taken to alleviate this problem, such as space reservations for anticipated modernizations of the DD 963 and DLGN 38 Class ships.

The features of modularity are designed to alleviate these problems. Thus it should be readily apparent that modular combat systems-a platform configured for ready installation and containment, access and service connections, and simple module-to-platform interfaces-can go a long way in reducing the funding

I

T.

requirements of modernizations and conversions, and therefore make available more dollars for new construction. A technical report by WHEELER INDUSTRIES gives a comprehensive discussion of this particular subject [12].

Reduced Cost of N e w Construction

Economies realized through construction modularity have been recognized for some time now and the use of such techniques, as exemplified by pre-outfitted sub- assemblies, is rather widespread, particularly in construction of commercial ships. The key features of construction modularity are as follows:

"Ideal working facilities without interference and overlapping of trades" [ 131. Parallel assembly activities. Test and checkout accomplished in parallel with construction and prior to installation. Learning curve effects from pre-assembly of many identical or similar items. Ease of handling and installing fewer, pre- assembled units.

The proven benefits of these features are reduced time and cost [ 131 [ 141 [ 151 [ 161. Modular construction is not being proposed here as something new, since the shipbuilding trend is in this direction. How- ever, a wide-scale modular approach by the NAVY, particularly in regard to combat systems, can only

208 Navdl Engineers Journal, April 1975


enhance the stated benefits of modular construction. After all, largescale pre-packaging is synonymous with modular construction. It only makes sense that further pre-packaging, say of combat system elec- tronics and weapons, will have the same effects as the pre-assembly and outfitting of construction modules. Simplified interfaces through consolidation and elimination contribute to the ability to parallel test and checkout prior to installation if such simplification results in an essentially independent module (i.e., minimal dependence on ship services to function). More significantly, after shore-side test and checkout, the installation of the package is certainly made easier by fewer and simpler interface connections.

Service trunking and distribution centers, shipping/ unshipping routes, and installation/removal openings, which are platform related modularity features, also facilitate parallel test and checkout prior to installation. Such provisions allow installation of entire prepackaged modules later in the construction schedule after much of the ship has been finished. Without these provisions, large packages would have to be installed earlier before the ship is closed, or the package would have to be broken down into smaller individual components, installed after “close-up,” then interconnected, and finally tested out-all in series.

An important point to note is that the ability to install modular electronic packages late in the construction schedule allows more time for delivery of long-lead GFE items, thus reducing the Government’s risk of late delivery and associated claims. In spite of a possibly increased hull volume, the net effect of these benefits is reduced unit construction cost of new ships, resulting in more ships for the same amount of money. An added benefit could be the reduction of the time of construction, resulting in a more rapid influx of ships into the Fleet.

Reduced Rate of Retirements

The rate of ship retirement is either a function of obsolescence or durability. Modernization and conversion has been, for many years, the NAVY’S answer to obsolescence. In a previous Section, we have discussed the positive contribution of modularity to modernization conversion, so we can limit our discussion now to the question of durability.

Given a continuing update of a ship’s combat system to avoid obsolescence, the platform, with its hull, mechanical and electrical systems, becomes the limiting factor. Ships are by necessity retired because these systems simply wear out and the cost of repairs be- gins to exceed the capital costs of a new ship investment. The only way to delay retirement is to build in longer life through the use of more reliable and durable hardware. Considerable headway has been made toward this end. and life expectancy of naval combatants has increased from 20 to 30 or 35 years. This improvement in life expectancy has come as the result of technological advances, particularly in material, lubricants and manufacturing processes. The applica-

tion of modularity can assist to some degree if the building-block approach and standardized basic components were to be applied to platform systems. As previously discussed, high-failure-rate submodules could then be substituted by more reliable replace ments while the basic, more durable, segment of the system in question remains intact.

MODULARITY: IMPROVING OPERATIONAL EFFECTXVENJES

The purpose of this section will be to evaluate how modularity can help improve operational effectiveness by meeting the following detailed objectives:

Reduced combat system development time. Reduced ship platform development time. Parallel development of combat system and platform. Reduced time required for modernization and conversion. Incremental, more frequent modernization a t the component level to reduce the Military Worth- Decay rate.

Reducing Combat System Developmat Time

Modern naval combat systems have reached a level of complexity that makes the development of new, advanced systems increasingly time-consuming and costly. This has been partially the result of over- centralization. Modularity, and in particular its features of component standardization, interface simplification, and decentralization via direct functional mechanization, is offering a fertile ground for application. Extensive use of standardization may allow reapplication of proven components in the new system with little or no additional development effort required. Other benefits of standardization, such as high volume production leading to lower cost and higher reliability, are discussed elsewhere. The NAVY’S Stan- dard Hardware Program [ 6 ] , again, may serve as an excellent example of how new, advanced systems can be developed using primarily (up to 80% and higher) proven components.

Reducing Ship Platform Development Time

The benefits of construction modularity have already been discussed in the context of construction cost savings. Its features will lead to a reduced construction time simply by allowing steps involved in the construction process to be taken in parallel rather than in series and in an environment more conducive to efficient working. As pointed out, these advantages are generally well recognized, and most modern ship- yards make extensive use of construction modularity.

Parallel Development of Combat System & Platform

Development concurrency is very strongly dis- couraged, if not prohibited, in current Department of

Naval Engineon Journrl. April I975 209


Defense (DOD) development policies for very good reasons ; unknowns, when compounded, tend to mul- tiply rather than add. I t should be borne in mind that DOD policies tend to be tailored towards weapon system acquisition in general. Weapons, however, always will tend to push the state-of-the-art. Known, as well as unknown, factors are inherently a part of any advanced development. Mandatory prototyping, as stipu- lated in existing directives, is therefore, generally a prudent requirement.

Naval ship system development, however, consti- tutes a special case, since the platform is generally not developmental and thus not characterized by unknowns. Modularity, therefore, has the potential to permit or- derly parallel development of warship payload sub- systems and the platforms that will carry them without risk due to concurrency. The risk of a parallel or a widely overlapping payload development and platform development can, to a large extent, be controlled by pre-negotiating interfaces and then adhering to them in the course of the concurrent development.

The penalties of series development are substantial. When deriving the detailed objectives that would help improve operational effectiveness, the loss in terms of Military Worth was shown in Figure 6. It is conceivable that in the extreme case, a ship’s weapon suit could become obsolete before a ship of the same Class, but later in the series, is delivered. This may lead to modernization and conversion of some ships concur- rently with new construction of others. The DE 1052 Class may just be one of those cases. Figure 11 shows the construction schedule of the DE 1052/DE 1978 Class. The shaded area shows when modernizations and

~ODEIIIlAlIOIICOIVLRSlOl OIGOIMG

Figure 11. Modernization/Conversion Overlapping Con- struction of Large Series (DE 1052 Class).

conversions were on-going while other ships of the same class were still being built. The first one to be converted was the U S S Trippe (DE-1075) which un- derwent modifications as follows:

1) Ship-to-ship missile capability added using the standard missile from ASROC launchers.

2) LAMPS helicopter added (deck designed for DASH; roof of the DASH hangar had to be raised two feet to house LAMPS).

3) One mount of SEA SPARROW added for surface-to- air capability.

Due to the distinction between payload and platform of a naval ship and in view of accelerated pace of technological evolution of naval ship weapon systems, the luxury of series development of weapons (seven years) and the platform (additional seven years) can no longer be afforded. Modularity would allow widely overlapping development.

Reduced Modernization and Conversion Time

The Worth-Decay phenomenon occurs in the case of a weapon system being installed on an existing ship, as it does for a weapon system awaiting the completion of a new construction. Ease of modernization and conversion, on the other hand, is perhaps one of the most widely publicized reasons for application of modular concepts. It has already been discussed in the context of exploring the possibilities of shifting funds to the new construction budget. The time lost in the course of modernization and conversion is shown in TABLE 1 for several actual cases; the average duration for the ships listed amounts to a staggering 28 months!

When advocating the application of modular concepts in order to reduce modernization and conversion time, it is emphasized that prepackaging, or even containerization without interface simplification and improved integration methods (combat system integration in particular), will do little. However, by selecting the proper balance of modularity features, significant time savings seem likely as the result of: a ) configuration standardization, b) interface simplification, c) ease of handling, and d) shore-side check-out of intra- module and, possibly inter-module functions.

Incremental Modernization at the Component Level

Part A of Figure 12 illustrates the current approach to modernization essentially replacing the obsolete. It is readily apparent that a low average Military Worth results if replacement is postponed until system obsolescence.

Modularity offers a very promising alternative resulting in a significantly higher average Military Worth as shown in Part B of Figure 12. It can be achieved by not waiting until a complete system is obsolete, but by updating at regular intervals certain key components of the system that are most prone to obsolescence, yet leaving major parts of the system

210 Naval bqinoorr Journal. April 1975


SVSTEM c

A . M 0 0 E R N I Z A T I O I V I A S V S T E M R E P L A C E M E N T

8 . I M C R E M E N T l L M O O E R N I Z A T I O N A T THE C O l ? P O N E N T L E V E L

Figure ‘12. Incremental Modernization Prior To Systems Obsolescence.

unaffected. Prerequisites for being able to do this are: a ) functions judiciously allocated to allow developmental efforts to concentrate primarily on those crucial components with the fastest rate of outdating, and b) developments adhering to interface and configuration standards, such that overall compatibility is preserved.

As an example, if a missile becomes outdated, it becomes necessary to pinpoint the origin of the obsolescence. It may be that the propulsion unit, the structural elements, and the mechanism for flight control are all perfectly capable of fulfilling their re- spective requirements. Obsolescence may be solely confined to the guidance unit; it would then be desirable to develop an advanced unit which can be made to fit the confines of the spaces occupied by the old unit. This approach can be implemented only if the initial design of a system adheres to “design-for- change” requirements extended to the component level.

MODULARITY: MORE AVAILABLE SHIPS

The operational availability profile of a typical modern combat ship was displayed earlier in Figure 7. It was shown how a significant portion of the ship’s lifetime is lost while the ship is either “off-the-line’’ to be modernized, converted, or overhauled, or is less than fully available because of reliability/maintainability problems. How modularity can lead to reduced modernization and conversion time, in addition to cost savings, has already been discussed. This leaves the subjects of overhaul, maintainability and reliability to be addressed.

Decreasing Overhuul, Maintenance, and Repair Time

Ease of overhaul and maintainability is signiflcantly enhanced by allowing a simple “plug-in” type approach. It allows the further option to discard (in lieu of repairing) a failed part, if economically justifiable. Otherwise, off-site maintenance, either in the ship’s own repair facilities or shoreside, is possible, but requires a rotatable pool of spare parts.

If the application of modular concepts is extended to include truly interchangeable portions of a ship’s payload, it will require some changes in the operation, maintenance, and logistics support concepts of the units that are not necessarily associated with a particular ship. The NAVY presently has only a few examples of such payloads: aircraft, MARINE or ARMY detachments on amphibious ships, and various special mission units.

Increasing Reliability

It is recognized that the reliability problem facing modern, complex and sophisticated combat systems is enormous. Modern combat systems are comprised primarily of high technology components in extremely large numbers. The overall reliability for some of these systems has been shown to be less than 50%. If systems were designed on the building-block principle, high failure elements could be redesigned indepen- dently as the state-of-the-art advances, and then be exchanged with substandard elements quite easily without impacting the basic system. In this fashion, product reliability and capability can be improved without having to resort to totally new system development and replacement.

Dramatic improvements, which may be obtained by using modularity concepts a t the component and parts level, are reported by MERZ [6]. Standard Hardware Program (SHP) modules were used to upgrade the Signal Comparator Cabinets of the AN/BOG-ZB, 4A sonar. After 32,745 system hours for ten (10) production units, the demonstrated MTBF value is 729 hours, as compared to 150 hours for the old cabinet. If failures attributable to a single design deficiency (a solder connection, now corrected) are excluded, the MTBF value for the modular cabinet increases to 1637 hours-an order of magnitude improvement.

The Potential for Z w e m e d Availability

In an earlier section, Figure 7 showed the time a normal ship is currently “on-the-line’’ and the com- posite availability normally achieved. A dramatic improvement, which could conceivably be achieved by extensive application of modular concept, is illustrated in Figure 13. Included is a partial concurrence of payload and platform development, as discussed previ-

Furthermore, it has been assumed that extensive use of modular concepts can reduce “off-line” periods by 50%. This would mean a modernization requiring

ously.

Naval Enqinearr Journal. April I975 211


about 10 months rather than about 20 months, and so forth. In view of the excellent results to date of the Standard Hardware Program in improving system availability, an increase of average system availability from 85% to 95% is conceivable.

Nevertheless, the lack of proof for these assump- tions renders Figure 13 more the illustration of a goal rather than of documented facts. This goal, however, is considered achievable, and the one concept most likely to achieve it is the modular concept since it can reduce all time periods distracting ships from serving their intended purpose.

SUMMARY A N D CONCLUSIONS

Much has been said about modularity. Various schemes have been proposed and the advantages and disadvantages have been discussed. Yet the question of whether or not the concept is worthy of significant investigation by the NAVY has been left unanswered. The purpose of this paper has been to answer this question.

To consider the worth of any new concept properly, the NAVY’S most pressing problems and its overall policy and goals must be addressed. The overriding

problem of the NAVY was shown to be deteriorating force levels in the face of a continually shrinking budget and an increasing Soviet threat. The essential, overall policy of the NAVY has been identified as the maximization of its “Return-On-Investment”-a policy which is important at all times, but which is particularly critical under the current conditions. The return aspect of this optimization function is expressed in terms of 1) number of ships, 2) operational effectiveness, and 3) operational availability.

The detailed objectives, consistent with NAVY’S policy and goals, have been identified as follows:

1) Increase quantity of ships- a ) Shift funds to SCN from other NAVY budget

categories. b) Reduce cost of modernization and conversion. c ) Reduce cost of new construction. d) Reduce time of development and construction

of new ships and modernizations/conversions. e) Increase ship longevity.

a ) Reduce combat system development time. b) Reduce ship platform development time. c) Develop combat system and ship platform in

2) Increase operational effectiveness-

L E G E N D AVAIL A B I L I T Y P R O F I L E F O R E X ISTING S H I P S

m y ADDIT I O N A L A V A I L A B I L I T Y OF A MODULAR SHIP MOD/

ROH M O D R O H MOD R O H CONV R O H ROH + * + .c + 1, 4 * I

I I 1 1

I o ’ r

-16 - 1 4

I I I I I I I I I I I I I I I I I I I I I I

L - 7

S H I P D E S . , L PROD.

2 5 30 I - I . -

P R I M E OPERATIONAL L I F E

( S E E ALSO F I G U R E 7) & PROD.

Figure 13. Operational Availability Profile for Modular Ships.

212 Naval Enqin**o Journal, April I975

I TABLE 2 C O R R E L A T I N G F E A T U R E S OF M O D U L A R I T Y WITH D E T A I L E D OBJECTIVES FOR M A X I M I Z I t l G ROI. I

parallel. d ) Reduce time of modernization and conversion. e ) Modernize frequently a t component level.

a ) Reduce time of modernization and conversion. b) Reduce time for regular overhauls and re-

stricted availabilities. c ) Increase component reliability. d) Increase component maintainability.

3) Increase operational availability-

It cannot be over-emphasized that all newly proposed concepts should be evaluated against these detailed objectives. There has been continual concern, on the part of R&D managers when faced with over- whelming numbers of new pmposab, as to which proposed concept is more important than another. The criterion of maximum “Return-On-Investment” should be used to establish priorities.

It becomes apparent when reviewing these objectives

Naval Enqimn Journal. April 1775 213

that time is as important as cost. F o r instance, the objective of reducing time of development and construction of new ships and modernizations/conversions contributes directly to increases in quantity, effectiveness, and availability of naval ships. Furthermore, a recurring theme of these objectives is t h e need to make provisions for likely changes to the naval ship’s combat system payload.

Modularity is synonymous with “Design-for-Change.” Change, particularly in the area of warfare, is inevitable; i t is caused not only by a high rate of obsolescence due to rapidly advancing technology, but also by the changing threat of a potential adversary. Provisions for this inevitable change are only sporadi- cally being designed into new systems. This makes the change, once i t finally comes, more painful in terms of cost and time expenditure; and it causes a postpone- ment of modernization with the result that many of our systems currently in service approach or even reach obsolescence before being modernized.

The concept of modularity in one form or another make a positive contribution to all of the NAVY’S primary objectives, as shown in TABLE 2. The contribution is greater in some areas than in others, but the concept has far-reaching potential. We have shown that if t he NAVY wants more ships, which it does, modularity can help; if t he NAVY wants a more effective Fleet, which it does, modularity offers significant potential ; and if t he NAVY wants more available ships, which it does, modularity is at least in part t he answer. Modularity makes sense simply because it allows the NAVY to improve its return on an increasingly constrained defense budget, as summarized in Figure 14. THE LOGIC FOR IMPLEMENTATION IS INESCAPABLE.

M 0 D U I A R I T Y

MORE EFT E C T I V E IWIPS (QUALlTV)

A C C f L f R A T E D

1

REFERENCES

[11 Currie, M. R., DDR&E, et tcl., “Statement of Princi- ples for Defense Research and Development,” De- partment of Defense, 1974.

[21 Moorer, Thomas H., Adm. USN. “US. Military Pos- ture for FY 1974,” Intematwnal Defense Review ( April 1974).

[31 “Recommendations for Improved Utilization of MDCS in Management Planning,” Sigma Systems, Inc.. NAVSHIPS Code 0411 Contract N00024-70-

[41 Smith, P. B.. Capt. USN. “Today’s Problems in Fleet Effectiveness.” Proceedings of the NMC Fourth Systems Performance Effectiveness Conference, May 1968.

[51 American Heritage Dictionary of the English Language. New York. N.Y.: Houghton Mifflin Co.

[61 Merz. John A., “The Navy Standard Hardware Pro- gram,” Naval Engineers Journal Vol 86, No. 5 (Oc- tober 19741 pp. 79-91.

[71 Schmidt, W. and L. 0. Sadler, “Containerprinzip beim Waffeneinbau auf Kriegsschiffen,” Wehrtech- nik, October and December Issue (1972).

[81 “Interface Standard for Shipboard Systems,” MIL- STD-1399A ( Navy ) , 20 December 1972.

[91 Bergman, Dr. C. E., “The Use and Misuse of Com- puters, An Assessment of Real-Time Systems.” Tech- nical Director Presentation, NELC. San Diego.

[lo1 Jolliff, James V., Cdr.. USN, “Modular Ship Design Concepts,” Naual Engineers Journal Vol. 86, No. 5 (October 1974) pp. 11-30.

[ l l l Carpenter, John D., LCdr., USN., and Peter C. Finne. LCdr.. USN, “Navy Ship Procurement.” Naval Engineers Journal, Vol. 84, No. 6 (December

121 “Modular Systems Design Concept Feasibility Study,” Technical Report SRC-70-TR-N32-H-l. Washington, D.C. : Wheeler Industries, Inc.. Septem- ber 1971.

131 “Study of Modular Design of Deckhouse and Out- fit,” Technical Report No. 5475 ( P B 178196) for Maritime Administration. New York, N.Y. : J. J. Henry Co.. Inc., 1968.

141 “PF Program Producibility Items.” Bath Iron Works Corp. ltr. Serial No. 500.1 of 29 June 1973.

151 McQuaide, J . and K. Christensen, “Japanese Ship- building Practices,” Marine Technology (October

[161 “A Study of the Feasibility, Cost, and Benefits of Expanded Use of the Modular Concept in the DX// DXG Program.” Booz-Allen Applied Research, Inc. Report 3634, 23 January 1968.

C-5318.

1972) pp. 69-81.

1969) pp. 418-439.

REDUCED C1I1II. YPN. c t c .

Figure 14. Summary of Modularity Contribution to an Improved Keturn on the Savy’s Investment.

214 Naval Enqineerr Journal. April 1975

modularity: maximizing the return on the navy's investment

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