CHAPTER 12

MAINTENANCE

As a Gunner’s Mate, maintenance is at the heart ofyour profession. For you, the art of gunnery comesdown to your ability to get the “rounds out” on commandsafely. The reliability of your gun is directly related toyour skill as a maintenance person. This chapter willcover a wide variety of maintenance items. We willbegin by discussing the essentials of preventive andcorrective maintenance. Following this, we will discusslubrication, corrosion control, barrel maintenance, andtools. We will then discuss the content and use ofequipment maintenance manuals. We will also providesome practical instructions for performing commonmaintenance procedures, such as replacing hydraulicseals and making mechanical adjustments. Finally, wewill discuss some safety precautions that apply tomaintenance.

The information in this chapter assumes you have afunctional knowledge of the Maintenance and MaterialManagement (3-M) Systems. You may find it useful toreview the requirements of the 3-M Systems beforebeginning this chapter.

PREVENTIVE AND CORRECTIVEMAINTENANCE

LEARNING OBJECTIVES: Discuss thedifference between the maintenance completedby the ship’s force, tender repairs, and repairshandled by the shipyards. Briefly describe thePhased Maintenance Program (PMP) and itsprimary elements.

The term maintenance includes many differenttypes of tasks. However, all maintenance is classifiedas either preventive or corrective. In this section we willdiscuss the elements and implications of preventive andcorrective maintenance. The intent of this section is toprovide you with a sense of the importance of your rolein keeping your gun operating smoothly and safely.

PREVENTIVE MAINTENANCE

Of the two main classes of maintenance work, themost important, which accounts for most of the

maintenance work you do, is preventive maintenance.Preventive maintenance consists mainly of the regularlubrication, inspection, and cleaning of your equipment.The purpose of preventive maintenance is to preventmalfunctions before they appear and discover existingmalfunctions before they become critical. Preventivemaintenance is based on the well-known principle thatan ounce of prevention-in the form of adequate routinemaintenance-is worth a pound of cure-in the form ofemergency repair, replacement, and overhaul.

Preventive maintenance is neither dramatic norexciting. While the need for routine lubrication isobvious, you may envision your leading petty officer(LPO) as being a little obsessive when it comes to gunmount cleanliness and inspection. You may think timespent cleaning and inspecting components that havealways been in good shape to be a waste. However, youwill realize this time has been well spent when youconsider the impact that an undiscovered hydraulic leakor a missing retainer clip could have in the midst of firingthe gun. These situations represent major casualties justwaiting to happen with serious and sometimes fatalconsequences. By taking a little time and trouble to doroutine preventive maintenance now, you can saveyourself a lot of work later by heading off breakdownsand time-consuming emergency repair jobs.

The Navy uses maintenance requirement cards(MRCs) in the planned maintenance system (PMS) tomake sure routine maintenance jobs are done at therequired regular intervals—daily, weekly, monthly, andso on,—and no steps are forgotten.

MRCs are obtained from the Gunner’s Mate underwhom you work. They provide a step-by-step guide forperforming a specific maintenance action. MRCsprescribe the minimum required preventivemaintenance for a given gun mount. MRCs cover alllubrication, some inspections, and some cleaning.Anyone with a little training can perform maintenancefrom an MRC. However, an MRC will not tell you toinspect mechanical linkages for cracks or missingretainer clips while you lubricate each of its pivot points.It will not instruct you to determine the cause of a freshpuddle of hydraulic fluid on the deck under a piece ofgun loading machinery and initiate steps to have itrepaired. As you become more knowledgeable in gun

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mount maintenance, you will develop an appreciationfor the importance of these unstated commonsensepreventive maintenance practices.

As stated earlier, MRCs cover all minimumlubrication requirements. However, you or your LPOmay determine that it is necessary to lubricate certainmechanisms more frequently during very heavyoperational conditions. This is acceptable and showsthat you possess a good understanding of the actualpurpose of maintenance—to keep the systemoperational!

Inspections required by MRCs normally consist ofchecks that verify fluid levels in hydraulic and gearboxreservoirs and mechanical adjustments and clearances.The term inspection may also be applied toMRC-directed equipment operational checks, electricalcontinuity checks, and gun order checks.

A good example of cleaning maintenance requiredby an MRC is the removal of lubricants from the gunbarrel before firing and the removal of residue from thebarrel after firing. Other cleaning maintenance coveredby MRCs includes the cleaning of electrical contactsand the removal of excess grease from around greasefittings after they have been lubricated. The generalcleanliness of your equipment is also an importantfactor. Dirt and dried hydraulic fluid on machinerymake it less likely that you will notice a fresh leak ordamaged component. It is also much more pleasant towork on clean equipment.

In addition to MRC-guided preventivemaintenance, you have the system maintenancemanuals. These manuals contain detailed descriptionsof the operation and care of the gun systems. You shouldbe intimately familiar with these manuals. They includeall the clearances and tolerances for the mechanicalsystems of the guns as well as detailed procedures forcomponent replacement. MRCs do not require theverification of the majority of these adjustments andclearances. Over the years, mechanical equipmentwears, the hull of the ship twists, and mechanicaladjustments slip. For this reason it is a good practice toreview system maintenance manuals to identify theseadjustments and clearances. Routinely including theverification of some of these adjustments in yourpreventive maintenance schedule will serve to extendyour knowledge of the operation of the system whilehelping to ensure its reliability. These adjustments alsomake good topics for professional training. Mechanicaladjustments are covered in more detail later in thischapter. Further discussion on maintenance manuals isalso covered later in this chapter.

NOTE: Be sure to consult with your supervisorbefore attempting to correct any equipmentmisalignments.

Let’s tie all these ideas together as we close out thissection on preventive maintenance. As a maintenanceperson you have three good tools available to helpyou keep your equipment operating at peakperformance—MRCs, system maintenance manuals,and common sense. MRCs form the foundation ofpreventive maintenance by providing minimummaintenance standards. System maintenance manualsprovide additional in-depth system operation andmaintenance information. Effective preventivemaintenance requires a high level of technicalknowledge mixed with some good old-fashionedcommon sense. You can do the minimum requiredmaintenance and be within the letter of the law, but stillhave the least reliable gun on the waterfront, and beknown as a poor maintenance person. You may believethat you are a maintenance person because you cancomplete the MRCs assigned to you. However, if theextent of your maintenance expertise encompasses onlythe requirements of your systems MRCs, then you arereally only a maintenance person’s helper. Amaintenance person has, or is continually working on,an in-depth understanding of the system. When youinvest that little extra time on the gun while performingroutine lubrication, you can take a good look at the gunto make sure all is in order. You will see in the nextsection how preventive maintenance is the foundationof corrective maintenance.

CORRECTIVE MAINTENANCE

Corrective maintenance involves the repair orreplacement of gun components that have beenidentified as worn, defective, or broken. In the courseof routine preventive maintenance, you will discovercomponents that require repair. This is the idealsituation—find the casualty and repair it before it affectsthe operation of your gun in a firing situation.Occasionally, however, in spite of the best preventivemaintenance, equipment will unexpectedly malfunctionor breakdown altogether during an exercise. You mustacknowledge this eventuality and be ready to deal withit when it occurs. Remember, a comprehensivepreventive maintenance program will keep theseoccurrences to a minimum.

The more you know about how your equipmentworks, the better you will be at troubleshooting andrepair. Experience is a great teacher, but you cannotwait until your gun breaks down in battle to find out how

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to repair it. This is where the knowledge and habits youdeveloped in performing preventive maintenance reallypay off. The maintenance person who has studied andunderstands the details of how the system works willhave a head start in detecting the cause of anymalfunction. This is especially true of electronic controlcircuit casualties. Casualty diagnosis is the heart of thecorrective maintenance problem. Once the casualty hasbeen accurately diagnosed, component replacement isnormally a simple task. If you routinely experiencecasualties in your system during firing exercises,especially mechanical and hydraulic casualties, youneed to take a serious look at your preventivemaintenance habits. Constant test operation andinspection of your gun system is the only sure way todetect problems before they can get serious enough toput you out of action.

PLANNED MAINTENANCE SCHEDULES

Until now, your experience in PMS managementhas probably been limited to duties as a work centersupervisor. As a result, you were closely involved in theday-to-day upkeep of the cycle, the quarterly, and theweekly PMS schedules of your particular work center.As an LPO, you may frequently find yourself assignedas a group supervisor. This means you will besupervising other work centers within your division ordepartment. Consequently, you will be spending moretime in the upkeep of PMS schedules. As you can see,knowing how to makeup the cycle, the quarterly, andthe weekly schedule is an important aspect of a CPO’sjob.

Although the department head is responsible for thepreparation of the cycle schedule, this duty is oftendelegated to the chief. Special care should be taken inthe preparation of the cycle schedule because it willdirectly affect the long-range scheduling of PMS due tooperational schedules, overhaul cycles, and availabilityperiods.

The cycle schedule is used as the basis for thepreparation of the quarterly schedule. Concurrently, thequarterly schedule is used as the basis for preparing theweekly schedule.

Because you should already be thoroughly familiarwith the preparation of PMS schedules, it will not bediscussed at any great length in this text. Theseprocedures are described in detail in chapter 5 ofOPNAVINST 4790.4.

Maintenance Skills

In performing any type of maintenance, a Gunner’sMate requires specific information relating to theparticular equipment to be maintained and repaired.You must also possess the required skills and knowledgethat apply to the maintenance of a myriad of equipment.The information needed can be found in the particularOP of the system, but skill and knowledge take manyhours of dedicated training to develop and fine tune.

We can assume that you have developed thosegeneral skills by following the procedures as set forth inyour personnel advancement requirements (PARs). Asthe LPO, you must be prepared to teach those skills toyour subordinates. Your trainees will not be tooimpressed if you do not know how to take an ohmmeterreading or check the clearance of a microswitch. Youmust learn more about the overall and continuing planof maintenance and the responsibilities ofadministration, as well as the technical duties inmaintenance.

Maintenance Planning

A study of the occupational standards shows that theGM1 must be able to overhaul, repair, test, adjust, andrecord all authorized maintenance performed. Note thatnearly all the knowledge factors are required at the GM3and GM2 level, with exception of the principles ofreceiver-regulators, functions of fire control, and supplyprocedures. You are expected to have knowledge of thebasic geometric layout for drawings and sketches, to beable to prepare freehand sketches, and to read andinterpret diagrams and service instructions.

The success of any planned maintenance programdepends upon the cooperation you receive at theworking level. Your maintenance personnel need tounderstand how their day-to-day work of lubrication,cleaning, and similar routine upkeep helps preventcostly and time-consuming breakdowns and thesubsequent hard repair work.

The responsibility of the leading GM inadministering the PMS and the MDS is describedgenerically for PO1 in OPNAVINST 4790 (latestrevision). Planning the daily maintenance work is yourresponsibility.

System Preventive Maintenance

Preventive maintenance components are built intosome ordnance systems to help detect faults within the

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systems. One of these components is a ground detectionindicator.

The ground detection indicator is a continuousmonitoring system designed to detect a system ground.Since most control circuits in ordnance systems arepowered by ungrounded 115-volt, 60 hertz,single-phase current, the first ground is not veryimportant from an operational point of view. However,if the first ground is not discovered and a seconddevelops, the result could be an illogical and destructivesequence of system operation. The reason for this is thattwo grounds act as electrical conductor between thegrounded components. When the ground detectorindicates (by light or buzzer) that some of the controlcircuitry is grounded, you should determine the locationand cause of the ground. The elimination of mostgrounds and potential grounds is good maintenance andhousekeeping.

MAINTENANCE BY SHIP’S FORCE,TENDER, AND NAVY YARD

Most of the maintenance work on armament aboardship is done by the strikers and Gunner’s Matesthemselves as part of the ship’s routine. This is calledship’s force maintenance.

The ship’s force, however, does not have thefacilities or the skills to perform certain less frequent,but equally necessary, maintenance operations.Examples of this type of operation are repair of gunsightor boresight telescopes and calibration of pressuregauges. Work of this nature is done aboard repair shipsand tenders that have the equipment and skilledpersonnel required for this type of repair work,

Lastly, there are some jobs, like major overhaul ofhydraulic systems or repair or replacement of rollerpaths, that are customarily completed in shipyards.Such work may be completed by yard workers, by theship’s force, or by both. Maintenance work completedin shipyards is termed navy yard maintenance.

Routine overhauls are scheduled far ahead of timeat a specified navy yard for each ship. To get the mostout of the overhaul work, you must keep records ofmishaps, signs of defects, or poor operation of gunneryequipment so that each of the items can be taken care ofduring the overhaul. You must also keep records of allrepair work done by the ship’s force. Keeping therecords is part of your job; the weapons officer musthave this information to plan the overhaul work.Pending maintenance and equipment history records aremaintained as part of the maintenance data system

(MDS) that is a part of the 3-M Systems. ‘hedocumentation of equipment malfunctions is brieflydescribed in the “Common Maintenance Procedures”section of this chapter.

Work by tenders and repair ships is also scheduled,so it must be planned for ahead of time. Authorizedalterations (ORDALTs) are also made aboard theseships when possible, although some may beaccomplished by ship’s force but supervised andverified by the appropriate Navy Sea Support Center,Atlantic or Pacific (NAVSEACENLANT/PAC).ORDALTs requiring special team efforts will beaccomplished under the direction of NAVSEACENpersonnel and supported, as required, by the in-serviceengineering agent and/or contractor representatives.ORDALTs usually state by whom the work is to be done.Changes of a minor nature are authorized byNAVSEASYSCOM instructions.

The upkeep period is time assigned to a ship whilemoored or anchored or when the ship’s force and otherforces afloat can work to perform upkeep duties withoutinterruptions.

Special assistance in maintenance, especially fornew equipment, may be obtained from contract serviceengineers who are specifically trained for specificequipment, or from mobile ordnance technical units(MOTUs) which consist of military personnel who havebeen trained to handle certain equipment and can beassigned to instruct others in its use and care.

OVERHAUL WORK PACKAGES

All U.S. Navy ships are assigned regular overhaulavailability cycles for the purpose of maintenance andupdating/improvement of the ship and its installedequipment. The two types of availability are theRegular Overhaul (ROH), and the Phased MaintenanceProgram (PMP). As a leading GM, you will be closelyinvolved with the planning and implementation of theseprograms. In addition, you will also have to supervisethe maintenance of your assigned equipment throughthe use of Inactive Equipment Maintenance (IEM).

Regular Overhaul (ROH)

One of the most important considerations affectingthe performance of ship’s overhaul is the determinationof what work is actually to be performed during theROH. This phase of the planning process is developedinto the Ship Alteration and Repair Package (SARP) orthe Integrated Work Package (IWP) as applicable.

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Because the SARP/IWP is both a planning and workingpackage for ROH, it will be addressed at this time.

For most ships, a SARP is the document that definesand authorizes work to be done during the overhaul,assigns the level of accomplishing activity for eachwork item, and indicates cost estimates for eachshipyard job. The IWP performs the same functions forsmall ships (ARS/AFT/MSO) when the OPNAV4790.2K maintenance forms are arranged in order byship system. The purposes of the SARP (or IWP) areasfollows:

1. Integrates related customer work requirements

2. Resolves redundant and conflicting workrequirements

3. Identifies work on a ship system basis

4. Serves as the single source document for allcustomer authorized work

The SARP/IWP is maintained as a continuingdocument that contains the information necessary forthe following:

1. Estimating the overhaul cost and duration

2. Early decision making by higher levels ofcommand concerning budgeting, finding, operatingschedules, and overhaul duration

3. Commencement of additional advanceplanning, design work, and material procurement bythose activities responsible for supporting andconducting the overhaul

Key inputs for developing the SARP/IWP are asfollows:

1, The Current Ship’s Maintenance Project(CSMP) as submitted by the type commander to thecognizant Planning and Engineering for Repairs andAlterations (PERA) approximately 12 months inadvance of the ROH start date

2. Results of the Pre-Overhaul Tests and Inspection(POT&I)

3. Type commander Title “D” SHIPALTAuthorization Letter

4. NAVSEASYSCOM Title “K” SHIPALTAdvance Planning/Authorization Letter

For ships using the SARP overhaul package, thefollowing action will be taken (approximately 90 daysbefore the overhaul commencement or when the SARPscreening action has been provided to the ship):

1. Work discovered during POT&I and designatedfor IMA accomplishment will be documented on anOPNAV Form 4790.2K and coded for availability.

2. Work previously documented into the CSMPfile, but which was originally coded for other than IMAaccomplishment, and for which subsequent screeningaction changed the accomplishing activity to IMA, willrequire submission of a correction document (OPNAVForm 4790.2K) to change the type of availability code.

The above work items, along with those alreadycoded for IMA accomplishment in the ship’s CSMP file(plus any desired master job catalog items), will formthe IMA work package for preoverhaul and concurrentIMAVs.

The time between regular overhauls varies from 2years to 5 years. The interval is the maximum periodconsistent with keeping the ship infighting trim.

An analysis of the problem of building, overhauling,or converting ships reveals that the following factorsplay essential roles:

1. The ship must be available for the uninterruptedaccomplishment of yard work,

2. The contemplated work must be decided upon,arranged in order of priority of accomplishment, andactually authorized to be performed.

3. Sufficient finds must be available to cover thecost of the work

4. Material must be available.

5. Personnel must be available to do the work

Advance Planning

The advance planning stage of the regular overhaulbegins approximately 18 months before the scheduledbeginning of the overhaul. During this stage, the plansprogress from a very rough to a refined and definiteschedule. In the broad sense, advance planningprovides a solid foundation for the accomplishment ofwork on naval ships in all shipyards. Availabilities ofships are approved by CNO on a fiscal-year basis.Before they are approved, schedules are commented onby forces afloat and NAVSEASYSCOM,

The main factors considered in formulating theoverhaul schedule are as follows:

The home port of the ship

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The intervals between the previous overhaulavailabilities of the ship and the proposedoverhaul

The placing of the ship in the home shipyard orshipyards capable of performing any requiredspecial type of work

The provision of a level of work in all shipyardsto avoid laying off personnel intermittently

The probable availability of critical material onimportant jobs

Any special factors that may arise

The final approved schedule represents the bestcompromise possible. It is used as a basis for planningby the material commands, the shipyards, and the forcesafloat.

It is quite possible, in view of the remote, long-rangenature of the schedule, that changes and adjustmentsmay be required from time to time. As the need arises,proposed changes are evaluated and approved/disapproved by CNO. Changes in start or completiondates may be made by the type commander with theconcurrence of the shipyard commander or thesuperintendent/supervisor of shipbuilding (SUPSHIP)when the change is 3 weeks or less from the assigneddate.

Advance planning on the part of the ship’s personnelis necessary for a successful overhaul. Thecommanding officer must ensure that adequate plansand preparations are made for the accomplishment ofthe following activities:

1.

2.

3.

Work of ship’s force

Training of the ship’s personnel during theoverhaul

Security of the ship’s spaces, includingprotection against fire, flooding, theft, andsabotage

All work within the capacity of the ship’s forceshould be accomplished by the ship’s personnel. Aschedule of the work of the ship’s force should includethe names of the persons responsible for performing thework, the estimated date of completion, the estimatednumber of work hours required for completion of thework, and a list of the necessary materials or toolsrequired from the shipyard to perform the work.

Plans for training during the overhaul period shouldoutline the objective to be accomplished by the end of

the period. Local training facilities and fleet schoolsshould be used to the maximum degree consistent withobtaining a good overhaul.

While the ship is undergoing overhaul, specialprecautions against fire, flooding, theft, and sabotagemust be taken. The shipyard is prepared to help withmatters of security, but the responsibility forestablishing security measures remains with the ship’spersonnel. The overhaul plan should include thenecessary organization for these precautions.

PRECAUTIONS AGAINST FIRE.— Thegreatest continuous hazard to ships undergoing overhaulis fire. Disruption of fire-fighting facilities and burningor welding work in progress are the most dangerousconditions contributing to fire hazards. The ship’s forceis responsible for providing properly trained firewatches for each burning or welding job in progressaboard ship. All watch personnel should be instructedin the location of the shipyard fire alarm boxes nearestto (or on) the ship and the current shipyard directivesconcerning fires and fire fighting.

PRECAUTIONS AGAINST FLOODING.— Thepossibility of engineering spaces flooding through seaconnections or through leaks in piping systems must notbe overlooked. The security plan should requirefrequent inspections of all unattended spaces in whichthis possibility exists.

PRECAUTIONS AGAINST THEFT ANDSABOTAGE.— Responsibility for the security of theship against acts of theft or sabotage rests largely withthe security watches and the inspectors of shipyardwork. Security measures should be enforced tactfully,so shipboard personnel will not be offended. To reducethe possibility of theft, you should place all tools,valuables, and clothing in locked stowage. Stowagespaces within the shipyard may be available to the ship’sforce for this purpose. Acts of sabotage can best beprevented by the vigilance of watch and duty personnel.Periodic patrols conducted at irregular intervals throughship’s spaces and proper identification of all personnelboarding the ship are basic requirements for security.

Ship’s Force Overhaul Management System(SFOMS)

Effective management of resources is a continuingchallenge at every level of command in the Navy.Spiraling costs, the growing complexity of mechanicaland electronic components, and the limitations of funds,skills, and time available for proper maintenance ofnaval ships demand full use of the best management

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techniques. The SFOMS provides managementtechniques for the control of ship’s force work duringan overhaul The SFOMS also provides the necessaryelements for a smooth transition from an operatingenvironment to an industrial maintenance environment.

The commanding officer is directly responsible forthe effective accomplishment of all ship’s force jobs,and for the management of both human and moneyresources during the overhaul (availability) so that uponcompletion of the work, there is a dependable, trained,and responsible crew. At the same time, the ship’scompany must have the leave and recreation they need.SFOMS provides the tools to help in attaining thesegoals. The system provides for a staff of shipboardpersonnel to schedule, manage, and control work to beaccomplished by the ship’s force by

identifying work that must be done;

finding out what work force, materials, andfacilities are required and available; and

developing cost estimates and schedules.

In this way SFOMS helps achieve an effectiveoverhaul; that is, completion of the work at the least costand in the minimum time without sacrificing quality.However, SFOMS is no longer a required managementprogram; its use is at the discretion of the commandingofficer. Further information and guidelines for the useof SFOMS are located in the NAVSHIPINST 5450.180.

Phased Maintenance Program (PMP)

The PMP is a maintenance strategy in which depotlevel maintenance is performed in a series of short,frequent, phased maintenance availabilities (PMAs)instead of regular overhauls. To the maximum extentpracticable, repairs are authorized based on the actualmaterial condition of the ship and its equipment. Inaddition to innovative material support procedures,PMP contracts enable depot level maintenance to beperformed by a single contractor throughout a completeoperating cycle. The goals of the PMP are maximumship availability, improved operational readiness, andupgraded material condition.

Primary Elements of PMP

The primary elements of the phased maintenanceprogram consists of the operating and maintenanceschedules, the port engineer, the material supportinitiatives (prepositioned equipment), the classmaintenance plan (CMP), and contracting for PMAs.

O P E R A T I N G A N D M A I N T E N A N C ESCHEDULES.— Operating and maintenanceschedules incorporate PMAs of 2 to 4 months durationat intervals of approximately 15 to 18 months. Minorvariations allow for operating cycle differences betweenclasses. One PMA in the cycle is extended by 1 monthto include dry docking. PMAs include both repairs andmodernization.

PORT ENGINEERS.— Port engineers manage theplanning for, monitor the execution of, and evaluatemaintenance work on the small number of ships eachport is assigned. They carry out these functions throughpersonal observation and direct contact with ship’sforce, group staffs, NAVSEADET PERA, SUPSHIPs,TYCOM SUPPORT GROUPS, and other planningagencies. Port engineers are primarily concerned withdepot level repairs and secondarily with IMAVs. Portengineers are directly responsible to TYCOM staffmaintenance officers for planning, for work definition,and for screening recommendations. This includesconducting work definition conferences (WDCs).Through a memorandum of understanding (MOU)between TYCOM and the individual SUPSHIPS, therelationship between SUPSHIP and the port engineer isestablished, particularly regarding the jointauthorization of any growth work by the port engineerand SUPSHIP. (New work may only be authorized bySUPSHIP after TYCOM port engineer concurrence.)Port engineers, however, do not authorize shipalterations.

MATERIAL SUPPORT INITIATIVES.—Material support initiatives for PMP are the use ofprepositioned equipment for change-out instead ofrepair and contingency spares to prevent delays ofscheduled PMA completions because of the lack ofrepair parts. The prepositioned equipment is limited toa small number of major items, and the contingencyspares are kept at or near the industrial activity.

Readily available parts in the Navy or DefenseLogistics Agency (DLA) supply systems are excludedfrom contingency spares.

CLASS MAINTENANCE PLAN (CMP).— Theclass maintenance plan defines anticipatedorganizational, intermediate, and depot levelmaintenance requirements for systems and equipmentsthroughout the operating cycle. Except for “legislated”requirements, a CMP task does not imply mandatoryaccomplishment. The judgment of the port engineer,actual equipment condition, priorities, and riskassessment are part of the repair decision.

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CONTRACTING FOR PMAs.— Contracting forPMAs is generally accomplished by the award of anincentive type, multiship/multiyear option contract witha competent contractor, usually in the ship’s home port.Although in particular circumstances other types ofcontracts may be used, the main objectives of this typeof contract are as follows:

1. To avoid the requirement to specify an inflexiblework list before the availability is negotiated

2. To allow incentive payments for cost control,high quality, and schedule adherence

3. To allow the crew to live in home port duringshipyard periods

4. To obtain “learning curve” payoffs in the formof improved efficiency and familiarity for both shipyardand ship’s force, resulting in long-term savings indollars and workdays

Overhaul Maintenance Requirements

During an overhaul period, work that pertains to therepairing, docking, and altering of the ship is done bythe shipyard work force. At the same time, however,shipboard equipment is still maintained by ship’s forcepersonnel. Although most shipboard equipment is shut

down and not in use during an ROH, it still must be keptin the best possible condition of readiness. This isaccomplished through the use of Inactive EquipmentMaintenance (IEM). At the same time, the shipboardPMS package is going through a constant updatingprocess. The flow of PMS documentation involvedduring an ROH period is shown in figure 12-1. TheIntegrated Logistics Overhaul (ILO) concept wasdeveloped because of logistic support problems existingin the Supply Operations Assistance Program (SOAP).The ILO program provides more comprehensive PMSdocumentation and supply support for shipboardequipment, including equipment that may not beaffected during an overhaul. NAVSEA is responsiblefor the development and implementation of the use ofthe ILO program. Information about ILO-governedPMS procedures is contained in COMNAVSEASYS-COM Policy and Procedures Manual, Volume 4, (PMSPolicy and Procedures for ILO), SL105-AA-PRO-040/IL0.

As you can see, the PMS documentation process foran overhaul period starts long before the overhaulactually begins and proceeds through the ROH andafterwards. Table 12-1 lists the Pre-ROH, during ROH,and Post-ROH actions and responsibilities for a ship tomaintain its 3-M program while involved in an overhaul.

Table 12-1.—ROH-Re1ated 3-M Actions

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During an ROH, much of your equipment isnaturally going to be removed, partially dismantled, orshut down. However, some equipment must bemaintained while inoperative through the use of InactiveEquipment Maintenance. Essentially, IEM providesmodified maintenance for equipment that is to beinoperative for extended periods of time. Figure 12-2shows how a quarterly schedule is modified to includeIEM requirements. Shown are two quarterly cycleswith IEM beginning in the 23d quarter and ending 4months later during the 24th quarter. Basically theschedule remains the same, but the changes (as denotedby the circled numbers with arrows) are explained asfollows:

1. When making out the new schedule that includesa portion of the ROH, draw red-colored vertical lines onthe schedules designating the start and end of theoverhaul. Indicate the IEM status of the equipment byentering a II or III. IEM status categories are identifiedin chapter 6 of OPNAVINST 4790.4.

2. Considerations, such as whether the ship is indry dock under own-ship’s power or air conditioning isavailable, should be noted as aids in schedulingmaintenance requirements in the event that specificservices or conditions are necessary to complete thecheck.

3. Operational PMS should be scheduled as normalup to the beginning of the ROH period.

4. Indicate “YD” with an arrow-tipped line on theMIP line for the equipment that yard personnel orcontractors are responsible for.

5. Schedule operational PMS for equipment thatwill remain operational during the ROH.

6. From the IEM section of the MIP, schedule ingreen all lay-up and periodic maintenance requirements.Note the scheduling of periodic maintenance of adifferent periodicity than that specified on the MRC. Inthis case, for example, the W-2 will only beaccomplished monthly as designated by (M) written onthe schedule beside the W-2 requirement.

7. Schedule start-up maintenance, and if necessary,operational tests toward the end of the ROH period.

When making the transition into the operationalportion of the schedule, do not reschedule requirementsthat have been accomplished by IEM actions.

Weekly PMS schedules are modified in the samemanner as quarterly schedules by drawing a line through

the preprinted operational requirements and substitutingthe IEM requirements.

Guidelines for the proper use and documentation ofInactive Equipment Maintenance are located in chapter6 of OPNAVINST 4790.4.

LUBRICANTS AND CORROSIONCONTROL

LEARNING OBJECTIVES: Discuss thecharacteristic properties and functions oflubricants. Identify lubrication symbols usedon charts and drawings. Explain why corrosioncontrol is an important part of any maintenanceprogram.

If you grew up in a large city, perhaps the onlyconnection you had with lubrication was taking thefamily car to the garage or the gas station for greasingand an oil change. But, if you grew up on a farm or hada car that you had to keep in running condition yourself,you are well aware of the need for regular lubrication ofall moving parts. If your car had a burned out bearing,you learned a lesson that you are likely to remember.Since you have been in the Navy, you have heard a lotabout the importance of lubrication. We placeadditional emphasis on the subject in this section as wedescribe the different lubricants and lubrication toolsthat you will encounter. We will also discuss some ofthe fundamentals and practices involved in corrosioncontrol.

QUALITIES OF LUBRICANTS

Lubricants are of two general classes-oils andgreases. Oils are fluids; greases are semisolids atordinary temperatures. Both have several qualities thatdetermine their suitability for a particular lubricationjob. One of the most important is viscosity.

Viscosity is the measure of the internal resistance ofa fluid that tends to prevent it from flowing. It varieswith the temperature as well as with the nature of thesubstance. Petroleum jelly can hardly be said to flow atroom temperature, but it can be melted to a rather thinliquid. On the other hand, many kinds of oils flowreadily at ordinary temperatures but become muchthicker when they are cold. A fluid that flows easily hasa low viscosity, while a fluid that flows slowly has a highviscosity.

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Viscosity is expressed in terms of S.S.U. units.(S.S.U. means Seconds Saybolt Universal andrepresents the number of seconds it takes a givenquantity of the lubricant at a specified temperature topass through the Saybolt Universal Vicosimeter orViscometer.) The higher the S.S.U. number of alubricant at a given temperature, the more viscous theliquid. The Navy uses the S.S.U. measurement, ratherthan the S.A.E. (Society of Automotive Engineers),grades to designate lubricants.

The viscosity index (VI) is an indication of thevariation of viscosity of the lubricant with variation intemperature. The higher the index, the less the viscosityvaries with the temperature. Thus a high index is adesirable quality. You want a lubricant that will notsolidify and gum up in cold weather nor liquefy and leakaway in hot weather.

A viscosity index can be improved up to a point byputting chemical additives into the oil. (Additives areput in by the manufacturer. Do not try to brew up yourown special oil by adding anything to it.)

The flash point of a lubricant is the temperature atwhich it gives off flammable vapors. The fire point(always higher than the flash point) is the temperatureat which it will catch fire if ignited and continue to burn.The pour point (of an oil) is the lowest temperature atwhich it will pour or flow.

Oiliness is the characteristic of an oil that preventsscuffing and wear. You might think this depends onviscosity, but a complicated relationship of many factorsis involved. Certain substances have been found thatincrease the oiliness of a lubricant.

Chemical stability is the ability of the lubricant to“take it.” Certain oils and greases tend to deteriorateunder the influence of high temperatures, exposure toair or water, or introduction of impurities. A lubricantwith good chemical stability will resist suchdeterioration. You can often detect deterioration bychange in color, by formation of varnish or gumdeposits, by formation of sludge, by change in viscosity(of oil) or consistency (of grease), by hardening (ofgrease), or by other telltale signs. Change in viscositycan be more accurately measured by a viscometer, butserious change is easy for the expert to detect.

These signs of deterioration mean that thelubricating and corrosion-preventing qualities of thesubstances are impaired. You will find it useful to knowthe signs of deterioration in oils and greases well enoughto recognize them should they appear.

Lubricants, preservatives, and hydraulic fluids allprotect metal against corrosion, at least to a certainextent. Corrosion prevention is, of course, the mainfunction of a preservative. The corrosion-resistingqualities of lubricants and hydraulic fluids can beimproved by adding chemicals, called inhibitors. Ingeneral, inhibitors are added to the substance by themanufacturer before delivery to the Navy.

Other qualities or properties of lubricants are thedropping point, the penetration, the neutralizationnumber, the work factor, the viscosity change, and theaniline point. Chemists working with lubrications needto understand the meaning of these terms; we list themonly to impress upon you that not just any oil will do.

FUNCTIONS OF LUBRICANTS

Lubricants are used for three purposes-to reducefriction, to prevent wear, and as a protective coveragainst corrosion. As a protective cover againstcorrosion, the use is obvious. As a preventive againstwear, the use is equally obvious when you consider thematter of friction. Lubricants form a layer or filmbetween the metal surfaces that actually keeps themetals from touching. The moving parts literally rideon the lubricant. In the instance of two metal surfacessliding across each other where space cannot beprovided for ball bearings, the lubricants themselvesserve as liquid bearings. In all mechanical devices,lubrication is necessary to counteract fiction as muchas possible. The presence of only a thin film of lubricantseparating metal surfaces keeps machinery running. Ifthe film disappears, you have hotboxes, burned-out andfrozen bearings, scored cylinder walls, leaky packings,and a host of other troubles-the least of them beingexcessive wear. All of these troubles are the result ofdirect metal-to-metal contact without adequatelubricant.

Specifications

Because proper lubrication is an absolute necessity,selection of high-quality lubricants having the rightviscosity and other properties for each job is of vitalimportance. When you drive your car into the localfalling station and tell the attendant, “One quart of10W30 oil,” you are specifying the kind of oil you want.

Most lubricants, hydraulic fluids, cleaners,coolants, and related materials used by the Navy arepurchased under federal or military (MIL)specifications. These specifications supersede allspecifications formerly issued by the Navy. Table 2-3in NAVSEA OD 3000, Lubrication of OrdnanceEquipment, cross-indexes superseded Navy

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specifications and designations with the current federalor MIL specifications.

The specifications are identified by names,numbers, and letters. Lubricants, preservatives,hydraulic fluids, and many other items are often knownand referred to by these specification numbers andsymbols alone. An example of an item you haveprobably already used is MIL-F-17111—a powertransmission fluid.

Oils

Many oils used by the Navy in ordnance equipmentare identified by four-digit symbols preceded by theletters MS (military symbols). You need to be able toread and translate these symbols.

The following classes of MS oils are approved foruse in naval ordnance:

Class 1 – Aircraft engine oils

Class 2 – General-purpose lubricating oils (130°F)

Class 3 – General-purpose lubricating oils (210°F)

Class 5 – Mineral cylinder oils

The viscosity for oils of classes 1, 3, and 5 isdetermined at a temperature of 210°F and for oil of class2 at 130°F. These classes are straight petroleum-basedoils without corrosion inhibitors.

Now, assume the MS on a certain oil is 2135. Whatdoes this tell you about this oil?

The first digit tells you that the oil is class 2, ageneral-purpose lubricating oil. The last three digitsindicate the viscosity as 135 at a temperature of 130°F.That is how you read military symbols for oils.

On lubrication charts, note that the number of thelubricant to be used at each place is not repeated, but a“target” symbol is used instead. This avoids confusionwith the number used to identify the part to belubricated, which may be used several times in the chart.The meaning of the target symbol is explained in thenotes on the chart, as well as in OD 3000.

Greases

Lubricat ing greases are a mixture o fsoaps—commonly, calcium or sodium soap—andlubricating oil. The oil may be a mineral oil(petroleum-based) or a synthetic oil.

The purpose of the soap is to make the oil stay putat the point of application. The soap traps the oil withinits mass, but the actual lubrication is done largely by theoil in the grease. You might think of it as an oil-soaked

sponge. The heat of friction squeezes the sponge,melting the grease and releasing the oil to perform thelubrication.

Greases are classified according to the kind of soapused in making them. Each kind of soap has specificproperties.

Calcium (lime) soap grease will not absorb moistureor emulsify (separate into its original ingredients).Consequently, it is specified for general lubricatingpurposes where bearings are exposed. However,calcium soap grease has a low-melting point and is notsuitable for hot-running bearings.

Sodium-soap grease emulsifies in the presence ofmoisture but has a higher melting point. It should beprotected from moisture. It is used for ball and rollerbearings.

Other kinds of soap bases used in greases arealuminum soap and lithium soap, with others added tothe list through experimentation and test at laboratories.

Graphite grease, as the name implies, containsgraphite. The graphite acts as a mild abrasive to smoothroughened wearing surfaces, as a filler to smooth overany pits in the surfaces, and as a friction reducer.However, because of its abrasive action, graphite greaseshould not be used in bearings that are in first-classcondition, except under high temperatures whenordinary greases would be destroyed. Technically, sincegraphite grease contains no soap, it is classed as alubricant oil, but it looks and is applied like othergreases.

Gear lubricants are a mixture of high-viscosity oilsand just enough sodium soap to cause jellying. Gearlubricants are suitable for high gear tooth pressure andmoderate speeds where the design of the case is suchthat ordinary oil cannot be retained.

As with oils, the viscosity of greases varies withtemperature. If temperature changes make it necessaryto change oil, check your lubrication chart to find outwhether you have to change the grease too.

LUBRICATING TOOLS

Some lubricants are applied by smearing them onthe surfaces to be lubricated. You will most often use atool (grease gun, oiler, or grease pump) especiallydesigned to put the lubricant into the equipment througha lubrication fitting.

Grease Guns

Grease is applied by a grease gun, or pump, througha nozzle that is designed to match the fitting. Although

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ordnance plants and repair shops have electrically orpneumatically powered equipment, you probably willhave to depend on your own right arm for power tooperate the lubricating equipment. Therefore, in thissection we will discuss only the hand-poweredlubricating equipment you are likely to use.

Hand-operated grease guns are of two types,depending on how they are loaded. To load one style,you remove a cap that comes off with the handle andstem (fig. 12-3) and fill the body with grease, using apaddle or spatula. As you might expect, this method of

loading can be messy; it also exposes the lubricant todirt and moisture. A faster and cleaner kind of gun(fig. 12-3, view A) is loaded by removing the cap nutfrom the end of the hollow handle and forcing grease inthrough the handle with a handgun loader(fig. 12-4, view A) or a bucket type of lubricant pump(fig. 12-4, view B).

The handgun loader is a 25-pound containerequipped with a hand-operated pump and a fitting thatmates with the opening in the handle of the grease gun.The bucket type of lubricant pump makes use of loader

Figure 12-3.—Hand-operated grease guns.

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adapter and loader valve when it is used for loading agrease gun. One pound of lubricant is delivered withevery seven full strokes of the pump. The loader willdeliver lubricant only when the grease gun is placed onthe loader valve. The job is much less messy with theloader, and it protects the lubricant againstcontamination. Besides, you do not have to run back tothe storeroom to refill your gun.

Different nozzles can be attached to the grease gunfor different types of fittings. The lubricant pump hasvarious couplers and adapters that attach to the hose,allowing the pump to be used on different fittings.

A grease gun can be used for oil if the point to belubricated has the proper fittings, or an oil gun (fig. 12-3,view E) maybe used.

A lever type of grease gun (fig. 12-3, views C andD) is being introduced; it gives more positive lubricationthan the push type (Zerk) of grease gun.

When you need to apply large quantities ofgrease-as, for example, in a gun mount roller path-agrease gun is too small. The bucket type ofhand-operated lubricant pump (fig. 12-4, view B) holdsthe same amount of grease as the handgun loader and is

fitted with a pump operated with a lever. It has a 10-foothose with a hydraulic T-handle adapter and a 90-degreeadapter for working in cramped spaces. With this pumpyou can build up a lubricant pressure of 3,500 psi anddeliver a pound of lubricant every 20 full strokes.

The hand-operated lubricant pump can handle anytype of lubricant generally required on naval ordnanceequipment except greases of the calcium soap type.

If you can arrange it, use several grease guns-onefor each type of lubricant you will need. You can savetime by taking care of all the fittings requiring a specifictype of lubricant before going on to apply the next type.For example, if you are working on a 5”/54 mount, takecare of all the fittings around the gunhouse that requireMIL-G-81322 before working on those that takeMIL-L-18486. After you have finished with the gun,rammer, hoist upper end, and soon, repeat the sequenceof application down in the handling room.

Fittings

Grease f ittings are of several types—hydraulic (unofficially called the Zerk fitting, after

Figure 12-4.—Hand-operated grease pumps: A. Handgun loader; B. Bucket type of lubricant pump.

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its inventor), button-head, pin-head, and flush (fig.12-5)0

The hydraulic fitting protrudes from the surface intowhich it is screwed and has a specially shaped roundedend that the mating nozzle can grip. A spring-loadedball acts as a check valve. The nozzle will not slip offthe fitting during lubrication but can be easilydisengaged by a quick forward-backward movement.Figure 12-5, view A, shows a cross-sectional view of astraight hydraulic fitting, and view C shows hydraulicfittings made for different angles. They are made to fitalmost any angle and have different threads and bodylengths. When using a gun equipped with a nozzle forhydraulic type of fittings, just place the nozzle on thefitting and push forward on the handle. This slips thenozzle onto the fitting and, at the same time, builds uphydraulic pressure in the gun, forcing the grease out ofthe nozzle. Then relax the pressure. A spring forces thehandle back, ready for the next stroke. Three strokes areusually enough. Only one hand is needed to work thistype of gun. The grip action of the nozzle coupler holdsthe nozzle firmly to the fitting until it is pulled free.Hydraulic fittings are being replaced by commercialbutton-head and pin-head fittings (fig. 12-5, views D

Figure 12-5.—Lubrication fittings.

and E) that provide more positive connection with thegrease gun. The grease gun can be used with thebutton-head fitting by adding an adapter.

The flush fitting (fig. 12-5, view B) is flush with (orbelow) the surface into which it is set so that it will notfoul moving parts. It is also used where there is notsufficient clearance to install protruding fittings. Theflush fitting also has a ball type of check valve. Whenpumping lubricant using a gun equipped for the flushtype of fittings, you must exert a steady pressure againstthe grease-gun nozzle to keep it in contact with the flushfitting, since the nozzle has no grip on the fitting.Otherwise, the method of use is much the same as withhydraulic fittings.

The oil cup with the ball valve (fig. 12-5, view F) isthe most popular type for oil fittings.

As with other routine jobs, it helps to have astandard operating procedure that you can follow. Hereis one that will be helpful:

1. First, consult the lubrication chart and locate thefitting.

2. Clean the fitting carefully with a lint-free cloth.

3. Apply the correct amount of the specifiedlubricant. (Be careful of the amount you apply-toomuch will cause excessive heat in the bearing and strainthe grease retainers, while too little is on a par with toolate.)

4. Wipe all excess grease from around the fitting.

5. Check off the fitting on your chart. A fittingmust not be missed just because it is battered or frozen.A frozen fitting could mean that the lubricant holesthroughout the bearing are clogged. This means tearingdown the bearing and cleaning all parts carefully.Grease that fitting even if it requires an hour of extrawork. This is where a little extra tenacity can pay bigdividends later by preventing a major casualty. Plasticprotective caps are often provided for fittings. Thesecaps keep out contaminants and also aid in keeping thegrease in the fitting.

LUBRICATION CHARTS

Frequent reference has been made to the lubricationcharts. They are published in the OPs for older ordnanceequipment and on MRCs for all ordnance equipment.These charts are necessary to do your maintenance jobproperly. Copies of some charts maybe obtained foruse as checkoff lists. A sample chart is reproduced infigure 12-6. On it, you can seethe use of target symbols(Nos. 1 and 2) and schedules for lubrication. Large

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equipments have several charts or MRCs with numerousplaces indicated for oiling or greasing. It would be easyto forget some places or to use the wrong lubricant ifyou did not have the chart or MRC to guide you and tocheck off as you work.

Lubrication Symbols

On lubrication charts and MRCs, lubricants andhydraulic fluids are identified by symbols, each symbolsignifying a specific oil or grease. Examples are shownin figure 12-6. The symbols are identified in OD 3000.

Alternates and Substitutes

If the lubricant prescribed in the OP or MRC for apiece of equipment is not available, you may find itnecessary to use either a substitute or an alternatelubricant.

A substitute lubricant is one that will fill the needfor a limited time but does not have all the essentialproperties of the prescribed lubricant. As soon as theprescribed lubricant becomes available, all of thesubstitute must be removed, and the equipment must becompletely relubricated with the prescribed material.

An alternate lubricant is one whose characteristicsclosely resemble those of the prescribed lubricant so thatits removal is not necessary when the prescribedmaterial is available.

Alternates and substitutes for prescribed Lubricants(as well as for cleaning materials, hydraulic oils, andpreservatives) are listed in OD 3000. If none of thealternate lubricants are available, you must choose asubstitute. Keep in mind that the substitute should be asnear as possible to the specified lubricant in lubricatingand rust-preventive qualities, viscosity, and ability towithstand the temperature ranges of the equipment. Inbrief, when the prescribed lubricant is not available, usean alternate if you can, a substitute if you must.

STOWAGE OF LUBRICANTS

Lubricants and related materials may bestowed forlong periods before use. Although they are relativelystable, they are not inert, and proper stowage methodsare important.

Many factors contribute to the deterioration ofmaterials in stowage. The nature of their constituentsmakes them more or less susceptible to chemical andphysical changes. These changes are accelerated byelevated temperatures, humidity, exposure, and the

presence of certain catalysts. The principal physicalchanges are separation and contamination,

Oxidation is the most common chemical reaction instowed materials. It occurs when the material isexposed to air, particularly moist air, and is acceleratedby high temperatures and the presence of certaincatalysts. Materials containing soluble additives maydeteriorate by decomposition or precipitation of theadditive. These and other chemical changes canproduce such harmful substances as acids, gases, water,insoluble gum, and sludge. Animal and vegetable oilsare generally more susceptible to chemical change thanmineral oils.

Physical changes include separation of oils from thesoap component in greases and separation of insolubleadditives from the parent material in oils. Thesechanges may not be as serious as chemical changes,since a thorough mixing may restore the material to ausable state.

Rain, melted snow, and water vapor in theatmosphere can contaminate materials that are exposedor improperly sealed. Water vapor trapped in thecontainer before sealing can condense when the ambienttemperature drops.

Generally, containers used to package materialssupplied under specification requirements are suitablefor stowage purposes. The effects of overheating,insufficient ventilation, and proximity to dangerousmaterials must be considered when handling andstowing lubricants and related materials. Goodhousekeeping in handling and stowage areas should bestressed at all times.

Containers, when stowed, should be handledcarefully to avoid breakage. If they are stacked,overloading of the lower ones should be avoided, as thismay open seams and permit loss of material. To preventaccumulation of water in their upper ends, you shouldstow drums on their sides. Lubricants and relatedmaterials should be segregated from explosives andother dangerous materials.

Before containers are stowed, they should beinspected for corrosion, leakage, and complete closureof all plugs, caps, and covers. All corrosion should beremoved and the affected areas repainted.

During stowage, containers should be inspectedfrequently for leakage and corrosion. If tests indicatethat the contents of leaking containers are in satisfactorycondition, the materials should be transferred

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immediately to serviceable containers. The leakycontainers should be removed and destroyed.

Stowage areas should be inspected for adequatedrainage, foundations, and properly placed underundamaged tarpaulins. Any deficiency found duringinspection should be corrected immediately.

Vapors from oils, greases, solvents, and similarproducts are flammable. When the vapors are combinedwith air in certain concentrations, they may formexplosive mixtures that can be ignited easily by a spark,an open flame, or a lighted cigarette. To preventaccumulation of flammable vapors, you must ventilatestowage areas properly. To safeguard against fire andexplosion, you should display warning signsprominently. Keep oil-fire extinguishing equipmentavailable, and keep interiors of stacks open to permitentry of fire-fighting equipment. Only spark-enclosedforklift trucks should be used.

Flammable materials, such as oils, greases, andsolvents, packed in metal containers or overpacked infiberboard or wood boxes, are best protected whenstowed in prescribed areas. Your ship should have anauthorized stowage area for lubricants and otherflammable materials. You may find it tempting to stowyour often used grease gun and oil can in or near the gunmount. This is a dangerous practice and should beavoided. A temperature range of 40°F to 80°F is themost desirable for stowage.

Vapors from lubricants and related materials mayfrequently have a toxic effect on the human system.Every precaution should be taken to prevent excessiveconcentrations of such vapors in the air.

The following safety precautions should beobserved when you are working with materials that havetoxic effects:

1. Provide sufficient mechanical ventilation toreduce the concentration of toxic fumes to a safe level.When possible, ventilation should include an exhaustfor fumes as well as intake for fresh air.

2. When a safe level of ventilation is doubtful,workers in the compartment should wear an air linerespirator provided with a pure air supply.

3. Personnel working in a compartment wherefumes may be above a safe toxic level should alwayswork in pairs so that one person remains outside thecompartment as a safety watch at all times. The personoutside should have a respirator in case it is necessaryto enter the compartment to bring out someone who hasbeen overcome by toxic fumes.

In addition to the use and stowage of lubricants, newregulations are in effect that prescribe how lubricantsare to be disposed. This includes oil- and grease-soakedrags. Your ship will have an instruction that details thedisposal of these materials. As a petty officer, you mustsee that the regulations are observed by your personnel.

CORROSION CONTROL

Every member of the crew is expected to maintainhis otherliving spaces. Therefore, besides the technicalmaintenance details on your gear, you will also beresponsible for cleaning, painting, and similarhousekeeping work. It is the duty of the division officerto supervise the maintenance, the preservation, and thecleanliness of all spaces and equipment assigned to thedivision, but the actual tasks are usually assigned by thedivision LPO (this maybe a PO3 or PO2). That meansyou have to know how to do the work and be able toteach others. Basic Military Requirements,NAVEDTRA 12043, chapter 17, describes generalhousekeeping preservation, procedures, andrequirements.

As a GM, most of your cleaning and preservingwork will be done on metal surfaces, principally steel.The preservatives must protect the metal against rustand corrosion; the cleaning materials must clean thesurface before the preservative is applied.

Rust is caused by the slow burning (oxidation) ofiron. When iron or steel rusts, it combines slowly withthe oxygen in the air.

Technically, corrosion is not exactly the same as rustsince its meaning includes metal being eaten away byacid or by the action of salt water or other substances.Rust and corrosion are dangerous and destructivesaboteurs that attack unguarded metal at the slightestopportunity.

The way to protect metal from rust and corrosion isto protect it from the air. Paint is a good protective, butmany metal surfaces, such as moving parts, cannot bepainted.

The lubricants used on moving parts serve as rustpreventives to some extent, but often this protection isnot enough. These are temporary preservatives forprotecting metal from water and weather. Light oils andgreases are applied to exposed gun parts and mounts astemporary protection against corrosion. Brightsteelwork, such as exposed cam and linkage surfaces,should have such protection. Slushing oils, available inseveral grades, are provided for this purpose. All old oil

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and dirt should be cleaned from the part and the surfacethoroughly dried before new oil is applied.

Authorized Cleaning and Preserving Materials

Some lubricants (preservative lubricating oil for usein small arms and light machine guns) have preservativeadditives (rust inhibitors) and can serve for short-termpreservation, but no preservative is intended for use asa lubricant.

When lubrication is not desired, there are specialpreservatives (permanent type) that may be brushed orsprayed on the surface to be protected. Small parts of amechanism may be dipped. After treatment, thepreserved mechanism can be stowed for a long period.(The length of time depends on the characteristics of thepreservative, the kind of stowage, and so forth.)

A rust preventive that can be used either to protectexterior surfaces or (as when pumped through ahydraulic system) for preserving interior surfaces,tubes, and so on, is the thin-film compound,MIL-C-16173, that is available in several grades. Ahard-film compound is available for metal exteriorsurfaces only.

Rust preventives are not lubricants and should notbe used instead of lubricants. Before treating metalsurfaces with rust preventives, be sure to remove alltraces of rust and corrosion and all the old lubricant.

Be sure to remove all of the rust preventive beforeadding lubricant to ordnance equipment that has beenstowed with rust-preventive compound coating. OP1208, Instructions for Inactivation, Maintenance andActivation of Ordnance in Vessels in Inactive Status,gives step-by-step instructions for removingpreservatives from gun mounts and other ordnanceequipment. Chapter 5 of OD 3000, Lubrication ofOrdnance Equipment, deals with cleaners andpreservatives. It contains a chart of all of the cleaningand preserving materials authorized for use on ordnancematerials. This chart gives the specification number,characteristics, applications, national stock number,container size, and substitutes, while the text elaborateson the use of each item. Some of the materials will bedescribed very briefly in the following pages.

Dry-cleaning solvent P-D-680 (Varsol or Stoddardsolvent) is useful for cleaning away old grease, oil, andrust preventives. However, it is hard on rubber (use soapand water on that). Because of its irritating, flammablefumes, it should be used only where there is plenty ofventilation and where there are fire extinguishers handy.

Diesel fuel or kerosene can also be used for the samepurposes as dry-cleaning solvent. The correct solventmust be used since some solvents leave a residue orcause corrosion. Therefore, always check the OP for theequipment.

Spraying or splashing of the solvent must beavoided during cleaning. If the solvent were to fall upona bearing surface, it would cut or render the lubricantless effective, causing excessive wear. After the solventhas been used, the parts must always be wiped dry witha clean, lint-free cloth.

Removing Rust

When using abrasives to remove rust, be careful toselect the proper type (see OD 3000) and use itsparingly.

Never use abrasives without permission from theproper authority. Only experienced personnel may useabrasives or wire brushing. Carelessly used abrasivescan do more damage than rust. A few strokes of even afine abrasive could destroy the accuracy of manyclose-fitting parts that are machined to close tolerancesand could lead to costly replacements. Always beextremely careful to keep grit from getting into bearingsor between sliding surfaces.

After the rust has been removed, the parts must bethoroughly cleaned and dried. Avoid leaving yourfingerprints on the metal. Cleaned surfaces should notbe touched by bare hands before the rust preventive isfinally applied. When the surface is clean and dry, youare ready to start applying paint or a preservative.

Painting Pointers

Painting is one of your important maintenance jobs.Instructions for using the chipping hammer in preparingmetal surfaces for painting are outlined in Use and Careof Hand Tools and Measuring Tools, NAVEDTRA12085.

Except for special applications like camouflage, theprimary purpose of painting in the Navy is forpreservation, rather than decoration. You do not paintjust for the sake of appearance nor as a substitute forcleaning. When you do paint, you should do a thoroughand neat job. “Thorough means that you cover everysquare inch of the surface to be painted, and “neat”means that you keep paint off places where it does notbelong. You have learned from past experience that itis much better and easier to keep the paint off the placeswhere it should not be than to clean it off later. Alwayskeep paint off gaskets, brightwork, grease fittings,rubber parts and rubber-covered wires, electrical leads

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and contacts not protected by armor or conduits,instruction or data plates, and working parts of surfacesthat are normally supposed to be protected by a coat oflubricant.

The first thing to do when you are given a paintingjob is to remove the old paint, which you have beentaught to do properly. The paint stripping solutionrecommended in OD 3000 is 8 ounces of sodiumhydroxide (O-S-598 Type 1) in 1 gallon of near-boilingwater. Rinse it with clean, hot water after the paint isremoved. O-S-598 should not be used on aluminum,zinc, tin, terneplate, or lead.

Before applying paint, be sure the surface is cleanand dry. Paint will not adhere to damp or oily surfacesor to surfaces covered with dirt, rust, or solvent.Galvanized surfaces must be wiped with ammonia,vinegar, or a special priming solution called wash primerbefore the paint will adhere. Brush the solution on,allow it to dry, and then wipe it off. Never use anabrasive on galvanized surfaces.

Soap and water are one answer to the problem ofremoving all dirt and traces of old oil or grease frommetal surfaces to be treated with rust preventives, paint,or other preservatives. Wash away all soap, then see thatthe surfaces are dry; and, finally, apply rust preventives(or paint) without delay. It is sometimes hard to get atpockets or cavities where water collects; be sure theyare not neglected.

The standard finish for United States naval shipsuperstructures is a gray paint; the exact color andcomposition are prescribed by NAVSEA. You will alsouse gray paint for the exterior of gun mounts.

A prescribed gray-blue paint is used for exteriorsteel decks. Interior bulkheads and overheads arepainted with a white paint prescribed by NAVSEA, andinterior steel decks are usually finished with gray deckpaint, although white is prescribed for decks inammunition spaces. These are the general rules forpainting; you will receive details on painting jobs fromyour leading GM.

BARREL MAINTENANCE

LEARNING OBJECTIVES: Describe therequired care and maintenance of naval gunbarrels and the purpose of using the propertools, gauges, and inspection instruments.

Every gun used in the Navy has a bore and chamber.Taking care of them is one of the first duties of theGunner’s Mate.

Care of the bore and chamber is no once-a-year oronce-a-month matter. They must be cleaned, dried, andinspected before firing. They must be cleaned,inspected, and oiled weekly. They must be gaugedperiodically, and the bore must be decoppered whennecessary. Maintenance of the bore and chamber is animportant job-not ordinarily a very dificult one, butone that must be done properly and at the prescribedtimes.

Frequent reference has been made throughout themanual of the need for keeping your guns cleaned andlubricated. This has been done for a purpose-the needto emphasize the importance of your job in keeping yourequipment “fire-ready.”

TOOLS USED

With the exception of one or two small-armsweapons for which maintenance tools are usually issuedseparately, every naval gun is equipped with certainbasic maintenance tools and accessories. Larger gunsand mounts are, of course, equipped with more elaboratesets of tools, but all sets include, as a minimum, theimplements that are required for care of the bore andchamber.

Cleaning Gear

The bore and chamber maintenance tools andaccessories issued for the 5"/54 are typical of suchimplements. The wire bore brush (with the sectionalhandle), the bristle sponge, and the lapping head are thebasic cleaning instruments.

The sectional handle is a wooden rod with couplingsat both ends that can be fitted either to similar couplingson other sections or to bore maintenance tools, likelapping heads and gauges. In the 5"/54 set, there areseveral of these sections supplied so that, by joining oneto the other, you can make a pole of any appropriatelength for the job at hand. The number of sectionssupplied with any gun makes any part of the boreaccessible.

The bristle sponge is a cylindrical brush used forcleaning the bore and chamber. It fits onto the end ofthe sectional handle. When stowed, it is covered with acanvas protecting cap.

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The lapping head is a cylindrical block on which canbe mounted four removable spring-loaded segments. Itis intended for removing relatively slight constrictionsin the bore. In stubborn cases, you will need to use thewire bore brush. Its stiff steel wire bristles are effectivein all but the very worst cases.

The tompion is used to keep dirt out of the gun boreand chamber. It is not used when there is a likelihoodof condensation forming in the barrel with the muzzleplugged. It is also not used in wartime when there mightnot be time to remove it before firing. Sometimesplastic or canvas covers are used over the muzzle; theguns can fire through them if necessary (unless heavilyice-coated or if supersensitive nose fuses are used).

Gauges

The bore plug gauge is a metal cylinder accuratelymachined so that it just passes through the bore whenthe gun is new. After the gun has been put to active use,constrictions may develop in the gun bore. The boreplug gauge is used to locate these constrictions. On gunsof 5 inches or smaller, the bore plug gauge fits onto theend of a section handle in the same manner as thepreviously covered accessories or is attached to a lineand pulled through the bore.

The bore erosion gauge is used in the gun barrel tomeasure the amount of erosion of the metal caused byfiring.

NOTE: The Mk 9 Mod 0 projectile seating distance(PSD) gauge was developed to repIace the 5" Mk 2 boreerosion gauge for estimating velocity losses andpercent-expended conditions in all 5"/54 gun barrels.

The PSD gauge is similar in construction to the oldMk 2 bore erosion gauge. The major difference is thatthe PSD gauge measures the seating location of theprojectile, rather than the wear near the origin of thebore. For instructions and use of the Mk 9 Mod 0 PSDgauge, see OP 1549, NAVSEAINST 8300. 1, and MRCs.

Inspection Instruments

Visual inspection of the bore and chamber precedesand folIows cleaning operations. Alight, of course, isvery helpful in finding inadequately cleaned areas,pitted areas, rust or corrosion, deformed lands or riflinggrooves, cracks, or other deviations. A bore searcher isused on 20 mm and larger guns. Look for corrosion atthe muzzle end caused by salt spray.

If the chromium plating in the chamber of the boreappears pitted, the combat systems officer will decide ifit is bad enough to need replating.

PREPARATION FOR FIRING

To prepare the gun for firing, you must inspect andclean the bore and chamber. Removal of the lubricantand the muzzle cover, or tompion, is but one of theoperations in the preparation for firing.

Removing the muzzle cover, or tompion, is easy. Toclean out the bore, however, you must wipe away thelubricant coating. In small arms, as you remember, thisis done with a cleaning rod and a patch. In larger guns,you use the sectional handle instead of a cleaning rodand clean toweling wrapped around the bristle spongein place of the patch. But the idea is exactly the same.

These instructions apply to guns that have been inuse and were given afterfiring care when last used Ifyou are preparing a gun barrel that has been taken fromstowage or if it is a new one, you have much more workto do. The preservative used on new or stowed barrelsmust be removed with dry-cleaning solvent. When allthe preservative has been removed, the solvent must bewiped out of the gun.

CAUTION

Observe ventilation and fire precautionrules when using dry-cleaning solvents.Remember also that solvents are drying andirritating to the skin and destructive to rubberand insulation.

AFTERFIRING CARE

Afterfiring care is more elaborate than prefiringcare. Every time a gun is fired, something besides thecartridge case is left behind. Deposits of corrosive salts(powder fouling) are left on the interior of the bore andthe chamber. As the rifling cuts into the projectilerotating band, some of the metal of the rotating band isleft behind as a deposit of copper in the bore (metalfouling or copper fouling). Both kinds of deposits areharmful and must be removed.

Standard maintenance procedure (postfiringmaintenance) is to remove the dirt and powder foulingsby washing out the bore and chamber with a Break-Freesolution (CLP#7) that cleans, lubricates, and preservesin one application. The gun is then secured until the nextfiring or a scheduled maintenance action. Pre- and

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postfiring barrel maintenance requirements are listed indetail on the appropriate MRC, normally a situationrequirement (R) card.

WEEKLY MAINTENANCE

Weekly maintenance is principally concerned withinspecting the bore and the, chamber for signs ofcorrosion and renewing the coating of oil. Decopperingand gauging may also be done at the time of weeklyinspection although they are usually apart of the beforeand afterfiring routine. Weekly maintenance isparticularly important during periods when the gun isnot being fired every day.

GAUGING

The plug gauge, described earlier, is used with guns3 inches and larger for detecting constriction of the bore.After the bore has been cleaned, attach the gauge to theextended sectional handle and pass it carefully throughthe muzzle until it clears the chamber end. If it passesthrough smoothly, the bore is not constricted.

If the bore has been constricted by copper fouling,the gauge will not pass. The next step is to mark the partof the sectional handle that is flush with the muzzle endto locate the constriction. Then draw out the gauge,remove it from the sectional handle, and attach thelapping head in its place. Push it into the gun bore upto the mark you placed on the handle and rotate it in theconstricted area. Use the cylindrical segments for thelands and the rifled segments for the grooves. A mixtureof pumice and oil maybe used as an abrasive. Continuelapping until the bore gauge will pass freely. Never tryto force the gauge through the bore; it may stick, causingdamage to both bore and gauge.

The plug gauge is the gauge you will use most inmaintenance of gun bores. But there are othergauges—headspace gauges, breech bore gauges, andstar gauges.

Information about the types and uses of gauges is insystem Ops and ODS.

DECOPPERING

We have already described the use of lapping headsand a fine wire brush (0.003-inch wires) to removecopper deposits in gun barrels. If the constriction is notremoved after a few trials with the lapping head, thedecoppering head maybe used. These are mechanicalor abrasive methods.

If there is metallic lead in the propellant, there ismuch less copper fouling when the round is fired. Thatis why older propelling charges were manufactured withlead foil in the case. However, the lead causes flash, andthe more lead, the brighter the flash, which you do notwant. To keep the flash to a minimum, you must keepthe lead in most charges to a minimum. Propellingcharges now being manufactured contain lead salts fordecoppering effect.

MAINTENANCE TOOLS

LEARNING OBJECTIVES: Describe the useof common hand tools, power tools, types oftorque wrenches, and special tools used in gunmount maintenance.

You must be familiar with the techniques and toolsrequired to maintain, repair, and adjust ordnanceequipment. Further, a GM must be able to select theproper general-purpose tools and special tools and knowthe safety rules applicable to their use. Maintenancetools can be classified as follows:

General-purpose hand tools

Power tools

Measuring tools and gauges

Torque tools

Special tools

HAND TOOLS

General-purpose hand tools are hand-powered andhand-operated. They are designed to perform simplemechanical operations. Examples of typical hand toolsare hammers, screwdrivers, and hacksaws. Generalinformation about hand tools is in Use and Care of HandTools and Measuring Tools, NAVEDTRA 12085.

POWER TOOLS

Power tools can either be electrically orpneumatically powered and are hand-operated. Theyare designed to save time and manpower, Examples ofpower tools used by the Gunner’s Mate are solderingguns, electric drills, and pneumatic grinders.

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MEASURING TOOLS AND GAUGES

Measuring tools and gauges are used for measuringand for layout work. Accurate measurements areessential for proper fitting and trouble-free equipmentoperation. Measuring tools and gauges range from asimple ruler to a highly accurate micrometer. Use andCare of Hand Tools and Measuring Tools gives adetailed discussion on all types of measuring tools andgauges that includes the common steel rules, calipers,micrometers, dial indicators, feeler gauges, and depthgauges. When studying Use and Care of Hand Toolsand Measuring Tools, pay particular attention to readingmicrometers and how to make feeler gauge readings.These two measuring tools are used for testing,checking, and adjusting many types of electrical,mechanical, and hydraulic units used with ordnanceequipment.

TORQUE WRENCHES

There are times when, for engineering reasons, adefinite pressure must be applied to threaded fasteners(nuts and bolts, as they are commonly called). Thispressure can be properly applied by a torque wrench.Proper torque aids in the locking of all types ofthread-locking fasteners. After tightening, nuts andbolts are held by the static friction of the nut and bolthead against the surface of the items being held togetherand the friction on the threads of the nut and bolt againsteach other. This friction is caused by the clamping forcecreated by a slight stretching of the bolt when the nut istightened. The metal, being slightly elastic, will pull

back toward its original dimensions, creating largeclamping forces. Excessive tightening will cause themetal to pass its limit of elasticity and cause a permanentstretch.

The principle of torque is based on the fundamentallaw of the lever; that is, force times distance equals amoment, or torque, about a point. Torque is often calleda torsional or twisting moment. It is a moment that tendsto twist a body about an axis of rotation. For example,if a common-end wrench is used to tighten a bolt, a forcetimes a distance, a torque is applied to overcome theresistance of the bolt to turning.

Figure 12-7 shows three torque wrenches-thedeflecting beam, the dial-indicating, and themicrometer-setting types. The deflecting beam isprobably the simplest and most common. The primarycomponent is the beam or measuring element. It is madeof alloy steel and maybe round, double round, straightflat, or tapered flat. To one end of the beam is attacheda headpiece containing the drive square (tang) and fixedpointer mounting. A yoke is attached to the other end.Mounted on the yoke is the torque scale handle and,when provided, the signaling mechanism. As a force isapplied to the handle, the beam deflects with the scale.The pointer remains fixed; hence, a torque is indicatedon the scale.

The torsion bar or rigid case dial-indicating type ofwrench, also shown in figure 12-7, has its actuatingelement enclosed in a rigid frame with a removableaccess cover. The deflecting beam, used in some rigidcase wrenches, is similar to that explained previously.

Figure 12-7.—Torque wrenches.

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The third torque wrench shown is themicrometer-setting type. To use this wrench, unlock thegrip and adjust the handle to the desired setting on themicrometer type of scale, then relock the grip. Installthe required socket or adapter to the square drive of thehandle. Place the wrench assembly on the nut or boltand pull in a clockwise direction with a smooth, steadymotion.

There are several different types of torquewrenches, but all of them have two basicparts-something that will deflect with the load andsomething to show how much the sensing element hasdeflected.

The torque wrench should be calibrated frequently.One that has not been recently calibrated and is notnormally stowed in its protective case should beconsidered as a dangerous tool. You cannot expect toget a meaningful reading from a precision instrumentthat has been abused. The flat- and round-deflectingbeam types will normally give true readings as long astheir pointers indicate zero and the drive heads are tight.Because this type can be kept in calibrations, it isrecommended for shipboard use.

Other types of wrenches that indicate by means ofdial indicator or by releasing or signaling when a presetload is reached are more sensitive to shock and dirt,hence should be calibrated whenever possible. Aminimum of 30 days between calibrations isrecommended. Never check one torque wrench againstanother.

An important point to remember always use theproper size wrench-the one with the desired torquenear the three-fourths mark of full scale.

When torquing, the critical maneuver is theapplication of force to the wrench handle. It must beapplied slowly and evenl y until the desired torque valueis indicated on the wrench scale. When installing a unitthat is circular or has more than one side, you shouldcross-torque the bolts. It may be necessary tocross-torque two to three times before an even torque isreached, but be sure the maximum torque is notexceeded.

Nuts and bolts should be tightened to the torquereading required by the installation drawings. Theformula often used is torque in foot-pounds is 0.2 timesthe bolt diameter times the desired bolt load. A load ofabout 60 percent of the yield stress of the bolt materialis used for most naval applications. However, bolt loadvaries depending upon whether the bolt or stud is usedto support the load itself or to hold together two

load-supporting members. Installation drawings willindicate the torque value specified by the designer.

If the bolts are loaded in tension, the torque must begreat enough to maintain tightness when the assemblyis unloaded and not so large that the bolts yield underload With this type of loading, all bolts must be equallytorqued to share the load.

NOTE: Always inspect for clean, lightly oiledthreads and clean surfaces before torquing. Discard allhardware with burred threads. For more detailedinformation on the use and care of torque wrenches,refer to Naval Ships’ Technical Manual (NSTM),chapter 075.

SPECIAL TOOLS

Special tools are used for one purpose and only onone type of equipment. They are supplied by NAVSEA,and instructions for their proper use are provided in theOps applicable to the specific type of equipment.

NONSPARKING TOOLS

Nonsparking tools are common hand tools andspecial tools made from nonferrous metals (metal notcontaining iron). These tools are used by the Gunner’sMate when working on or around explosives. Thesetools are generally made from a copper alloy (bronze).However, they may be made from other nonsparkingmaterials. Since these tools are made from a relativelysoft material, care must be exercised when using themto prevent breakage or distortion of the tool.Nonsparking tools should be stowed in separatetoolboxes and should not be used as common hand tools.

RULES APPLICABLE TO REPAIR TOOLSBEFORE A JOB

Before a job is started, all work procedures shouldbe planned and the proper tools selected to complete thejob. Tools not actually needed for a job should beproperly stowed in toolboxes or tool lockers.

The quality and type of all tools must conform withNavy standards.

All tools inactive use must be properly maintained.Defective tools should not be used.

Portable electric and pneumatic tools must be keptin the best condition possible. These tools should bechecked frequently by the tool keepers for defectiveswitches, electric cords, control valves, and hoseconnections.

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Extensions to the tool handles should never be usedto increase leverage.

PRESSURE GAUGES

Pressure gauges are used frequently in conjunctionwith ordnance equipment. Accurate pressures arenecessary to obtain proper operation of hydraulic,pneumatic, and nitrogen accumulator systems used inordnance equipment. Pressure gauges are also usedwith hydraulic test kits and magazine sprinkler systems.These gauges are the means of accurately measuringpressures in pounds per square inch (psi). Pressuregauges are used in weapon systems to measurehydraulic fluid pressures (oil gauge), magazinesprinkler system pressure (water gauge), counterrecoilsystem pressure (air gauge), and accumulator systemspressure (nitrogen gauge).

NOTE: Gauges used on weapons equipment areconsidered critical and require annual testing andcalibration.

The two most common types of gauges used withordnance equipment are the Bourdon and Schroederpressure gauges. The theory of operation of thesegauges is explained in Fluid Power, NAVEDTRA12964.

The following are some precautions to be observedwhen using pressure gauges.

Do not allow pressure to remain on gauges thatare permanently installed in hydraulic systems.

CAUTION

Never use a hydraulic fluid gauge fortesting air pressure, nor an air gauge for testingfluid pressure. A diesel action may occur!Diesel action is the ignition of hydraulic fluidby air that causes combustion.

Never use a gauge on any system in which themaximum pressure exceeds the maximumdesignated range of the gauge.

SOURCES OF MAINTENANCEINFORMATION

LEARNING OBJECTIVES: Discuss thesources of ordnance data and maintenanceinformation.

It would be impractical to try to squeeze into thischapter the many details you must know to performmaintenance, troubleshooting, disassembly, andreassembly to ordnance equipment assigned to you.Since there are many different marks and mods ofequipment performing the same function “but havingdifferent working parts, the Naval Sea SystemsCommand (NAVSEASYSCOM) prints a publicationrequirement list for every active-duty ship now inservice. This list is based on the major units installedand lists all the Ops, Ods, FMs, and TMs needed forrepair, maintenance, test, and operation of theseequipments. Copies of all the publications listed in thislist are furnished to the vessel as part of the originalcommissioning allowance. If additional copies arerequired, they can be ordered through the appropriatesupply point.

OP 0 is the index of the NAVSEASYSCOMordnance publications. It lists by number and subjectthe ordnance publications (Ops) and ordnance data(Ods) used in the Navy. OP 0 also lists all currentrevisions, changes, and supplements to OPs and ODs.In addition, it includes current Army field manuals(FMs) and Army technical manuals (TMs) used by Navyactivities. Your OP 0 may or may not be on microfiche.

ORDNANCE PUBLICATIONS

OPs are used by the operating forces and containdescriptions of ordnance equipment and theircomponent parts and instructions on how to operate,maintain, disassemble, reassemble, test, and adjust theequipment. All OPs have a section on safetyinstructions for operating the equipment and general andspecific safety orders when troubleshooting. The OPsare published by NAVSEASYSCOM, each under itsown OP number. Newer OPs are issued using the newTechnical Manual Identification Numbering System(TMINS). As older OPs are updated, they are oftenconverted to the new numbering system. They maybeprepared by some other naval activity, by themanufacturer, or by the command itself. Any changesto OPs are issued by NAVSEASYSCOM. Changesissued to the fleet are numbered and a record of allchanges is listed on a change record sheet posted in thefront of every OP. The information on these sheetsincludes the change number, the date the change wasmade, the title or brief description of the change, and thesignature of the person making the change.

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ORDNANCE DATA

ODs are a kind of catchall. They are used forpublishing advance information or instructions onordnance equipment installation and alignment data,parallax data, and other miscellaneous information,such as tables of weights and dimensions. ODs arenumbered consecutively by the issuing agency. ODs,like OPs, are listed in OP 0.

One OD that is required reading for you and for allother Gunner’s Mates is OD 3000, Lubrication ofOrdnance Equipment. It is the one OD that your ship’slibrary of ordnance publications must not be without.Other ODs maybe useful to you, depending on the typeof ship you are aboard and its armament. For thisinformation you should consult OP 0. If the ODs are notalready in your ship’s library, they can be ordered.

Revisions

Revisions are made to OPs and ODs when theoriginal publication becomes obsolete due to manydesign changes to the equipment. Revisions arenumbered and the latest revision supersedes theprevious one. When revisions of OPs are madeavailable, be sure you check the new OP for the purposeof the revision. In some cases, a revision maycompletely replace other OPs or ODs and theirsupplements. A statement in the front of each revisedOP or OD identifies those publications that are madeobsolete by the revision.

Changes

Changes may consist of pen-and-ink changes,complete page changes, or changes to drawings andsketches. Changes are made to OPs and ODs afterOrdnance Alterations (ORDALTs) have been completedor when errors and inaccuracies are found in apublication.

Supplements

A supplement is an addition to an OP or OD thatreflects changes to equipment or its operation madesince the OP or OD was published. The originalpublications are still used; the supplements describeonly the differences between the major assemblies or thedifferences between the marks and mods of gun mounts,missile launchers, and rocket launchers.

Supplementary Sources

At times, during the course of your work, you mayrequire information not covered in OPs or ODs. Whereyou find this information depends upon the type ofordnance equipment with which you are working. Ifyou are working with demolition equipment, forexample, explosives ordnance demolition bulletins(EODBs) could help you. Other types of publicationsare special weapons ordnance publications (SWOPs),NAVSEA instructions and notices for general policymatters, and such other publications as ORDALTS-00that supply information on all ORDALTs for aircraft,shore stations, and all classes of vessels.

The Army prepares several publications that arealso applicable to Navy ordnance. These include fieldmanuals (FMs), technical manuals (TMs), technicalbulletins (TBs), and joint publications of the Army,Navy, and Marine Corps. These publications are listedin the Index of Doctrinal, Training, and OrganizationalPublications, DA-PAM 310-3, U.S. Army, or SL-1-3,Index of Publications Authorized and Stocked by theMarine Corps (PASMC).

ORDNANCE DRAWINGS

LEARNING OBJECTIVES: Discuss the maintypes of drawings used in gun maintenance andoverhaul. Discuss the purpose of the illustratedparts breakdown (IPB) publication. Discussthe purpose of the standardized symbols usedin hydraulic diagrams.

To do any kind of maintenance work on yourequipment, you must know it well. A good way to learnabout it is to study the hardware itself. But you will learnfaster and you will learn more by using certain sourcematerials. This manual is such a source; so are the OPs,ODs, and other publications. In many ways, however,your most valuable source material could be ordnancedrawings.

All manufacturers of ordnance equipment makedrawings of all equipments they manufacture. Copiesof these drawings, reproduced by blueprinting, Xeroxprocess, or in some other way, are supplied to everynaval ship or installation that either has the equipmentor, for some other reason, requires copies of thesedrawings. Many drawings are reproduced in OPs andother technical manuals. Some of the drawings you willuse are made by NAVSEA, but many others are made

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by the contractors who manufacture the equipment forNAVSEA.

TYPES OF DRAWINGS

Drawings differ depending on their purpose. Themain types of drawings, as classified according topurpose by NAVSEA, are as follows:

1. General arrangement drawings. This kind ofdrawing shows the complete equipment assembled. Itindicates general appearance and relationships ofimportant component assemblies and identifies thedrawings that describe the components of theequipment.

2. Installation drawings. These drawings showsuch features as mounting pads and brackets, shockmounts, points for entrance of cabling and matingmechanical parts, type of cable required, dimensions ofmounting hardware needed, and directions for how toorient the equipment and secure it to its place on thebulkhead or deck. One variety of this type of drawing,called an outline drawing, shows overall dimensions andclearances required for operating and servicingequipment.

3. Assembly and subassembly drawings. Thesedrawings show the constructional details of theassemblies that make up the complete equipment. Ingeneral, you can think of an assembly (or subassembly)as any group of two or more parts assembled to makeup a unit. An assembly drawing is intended to enable aproperly equipped shop to make up the finishedassembly from the prescribed parts and assembly andfinishing materials.

4. Detail drawings. When you disassemble anypiece of equipment far-enough, you eventually get downto individual pieces that cannot be disassembled anyfurther. These are represented by detail drawings thatgive all the information that a properly equipped shopwill need to make the piece exactly as required.

5. Wiring drawings. The main purpose of a wiringdrawing or diagram is obvious from its name—it showsyou how to wire apiece of equipment or a system. Thereare several varieties of wiring diagrams.

An external wiring diagram shows how to connectan item of equipment to the ship’s wiring system or toother pieces of equipment. It shows terminal boards,binding posts, plugs, jacks, and other connection pointsand devices, and identifies them by letters and numbers.Lines denote the electrical conductors to be installed.The drawing shows the size and type of wire to be used;

the kind of insulation, shielding, ductwork, andarmoring specified, as applicable; length needed; whereground connections are to be made; where joints mustbe soldered, welded, or clipped; and so on. It alsospecifies the kind of current (ac or de), frequency, andvoltage for each conductor.

An internal wiring diagram does the same for wiringinside an equipment. It also identifies and shows wherethe fuses are, the size and type to be used, and theircircuits. It locates and identifies, with standardsymbols, all lamps, motors, synchros, resistors,capacitors, transformers, chokes, switches, relays, andall other electrical components in the equipment andgives their electrical values, as applicable. It identifiesall the terminals and connection points. This is one ofthe most useful kinds of drawings for electricalmaintenance and troubleshooting.

An elementary wiring diagram is about halfwaybetween the diagrams we have just discussed and theschematic to be taken up shortly. It shows terminal andconnection points, component locations and values, andsoon, but it is also arranged so that it is much easier tofollow and understand the circuit than with the usualwiring diagram. But note that the elementary, like thepure schematic, has little respect for the actual sizes andshapes of parts or equipment or for their physicallocation or orientation. The traceability of the circuit isa much more important consideration.

6. Schematic drawings. About the only generalstatement you can make about schematic drawings ordiagrams is that their primary purpose is to help the userunderstand the functioning of the equipment. Inordnance, schematics of electric, hydraulic, andpneumatic systems are of great importance in assistingyou as a repairman. Schematics often have very little todo with the actual physical appearance or constructionof the equipment diagramed.

7. Lubrication drawings. A lubrication drawing orchart for naval equipment is often a general arrangementdrawing, or a group of them showing several views,where lubrication fittings and other points are called outby labels. The OP on older equipment normally has alube chart in its appendix.

8. Tool drawings. Special tools, such as spannerwrenches, for specific marks and mods of guns aredescribed in tool drawings—usually assembly or detailtype. These tools are listed in the specific OP.

9. Lists of drawings (LDs). LDs, as mentionedpreviously, is considered by NAVSEA to be a variety ofsketches. In itself, this detail of classification is ‘not

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especially important in your job, but it is worthremembering that an LD looks like and is treated like akind of engineering drawing, rather than like apublication.

LDs are, in a sense, the key to the drawing systemused by NAVSEA. Beginning at the top of the system,a master list of drawings, or master LD, is prepared foreach major ordnance equipment (such as a gun mount).This list includes all components of the equipmentconcerned Each component is itemized by assemblies,subassemblies, and details on a separate LD.

The identifying number for each component LD isgiven, together with the general arrangement drawingnumber on the master LD for the equipment. Eachcomponent LD also shows the special tools required forservicing that component. By reference to the LD andthe drawings for the mark and mod of a given assemblyor subassembly, it is possible to work down to anindividual part and to identify the correct nomenclature,drawing, piece number, design dimensions, tolerances,and all other necessary information.

When we refer to a drawing or engineering drawingwithout qualification, we usually refer to an assembly,subassembly, or detail drawing. Such drawings, as wehave seen, explain how to manufacture some part orassembly. And they are also valuable guides for you inoverhauling and repairing equipment. These drawingsare valuable not only because they show how parts fit(though this is very important itself) but also becausethey describe and enumerate the fastening hardware youneed to put the assembly together (including the properbolts, nuts, patent fasteners, pins, etc.). They also showthe minor, but essential, parts that the assembly musthave so that it will continue to function as the designerintended. A watertight enclosure, for example, will leakif it does not have the exact gasket called for in thedrawing; screws may loosen if they have not beenassembled with the lock washers specified in thedrawing; and nuts will work free if they have not beensecured with the cotter pins listed in the drawing.

Other types of drawings are equally valuable.General arrangement drawings are good references forthe exact nomenclature of major units and as guides todrawings on component assemblies. Installation andoutline drawings contain just the information onclearances and dimensions that ship’s personnel requirewhen a new piece of equipment is to be installed, andthey show how to arrange the piping and wiring to beconnected to it. External wiring diagrams show justhow to hook equipment into the ship’s wiring. Afterinstallation, they aid in troubleshooting for faulty

circuits and malfunctioning components and inelectrical alignment of synchros and other datatransmission devices. Internal wiring diagrams areequally valuable for making circuit checks in case oftrouble in the equipment. Elementaries are helpful intraining personnel and can be used in checking circuits.And, finally, LDs are valuable guides in tracking downthe particular piece of information you maybe lookingfor.

Every ship carries copies of drawings on itsequipment in the form of blueprints, photoprints,microfilm, or microfiche. These copies are assembledinto sets, each set covering one item. Photoprints areusually bound in books. Aboard ship, both blueprintsand photoprints are called ordnance drawings.Blueprints and photoprints are available to you either ina special file in the repair shop or in the custody of yourdepartment head. Make use of them; they will help youbecome familiar with the ordnance you will overhaul.(Remember to treat Confidential drawings as you wouldany other Confidential publication.)

Down in the lower right-hand corner of eachdrawing you will find a drawing number. On each detailpictured in the drawing, you will find another smallernumber. These are the piece numbers. These numbersidentify both the hardware and the drawing. Sometimesyou will find a letter after the piece number showinghow many times that piece has been changed ormodified since the original design.

Every part of every ordnance device (unless it isvery small) has a part number stamped on it. The firstnumber is the drawing number; the second is the piecenumber. For example, you will find numbers like120460-2. This should read: “drawing number120460, piece number 2.”

Look for these numbers and use them. Refer tothem when you report on a particular piece or when youorder new parts.

ILLUSTRATED PARTS BREAKDOWN

An illustrated parts breakdown (IPB) is apublication usually in the form of an OP that describesand illustrates all components used in ordnanceequipment. An IPB is broken down into sections thatidentify component parts by major assemblies,subassemblies, and detailed parts. All illustrations inthese publications have figure and index numbers forproper repair part identification. The figure numberrepresents a unit; the index number identifies just onepart of that unit. Each unit has an identifying part

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number and accompanying each part number are thename and description of the part it represents. Partnumbers are then cross-referenced to a current NSN toorder replacements. The IPB illustrates the assembly ofyour equipment using expanded drawings. Theseexpanded drawings are very helpful in locatinglubrication fittings and other components that oftenelude a maintenance person.

Some IPBs have a cross-reference section thatconverts the identifying number to a part number ornational stock number (NSN). These cross-referencesmay not have the latest NSN; the appropriate section ofthe Coordinated Shipboard Allowance List (COSAL)should list all the latest NSNs. An index of IPBs is listedin OP 0.

HYDRAULIC DIAGRAMS

Hydraulic symbols are used throughout the worldin design, operation, and maintenance of fluid powersystems. A thorough knowledge of hydraulic symbolswill enable you to read and understand hydraulic circuitdiagrams and other drawings of hydraulic circuits.

Hydraulics today have many and variedapplications; therefore, a standardized set of symbolswas agreed upon at a joint industrial conference ofleaders . This conference recommended asystem of designating symbols that some of thecommercial manufacturers are presently using. Thesesymbols for fluid power diagrams are listed in USASY32.10.

Graphic symbols provide clear-cut circuitinformation, and well-prepared circuit diagrams showevery part of a hydraulic circuit clearly. Symbols areavailable for most commercial components. Drawingsthat use symbols will normally also supply a legend fortheir interpretation. Blueprint Reading and Sketching,NAVEDTRA 12014, and Fluid Power, NAVEDTRA12964, give some elementary information on thetheoretical background of drafting, on how to readdrawings of all types, how to sketch, what type ofinformation is found in a title box of drawings andschematics, and additional information on symbols usedin electrical, electronic, and pneumatic sketches,schematics, block diagrams, and mechanical drawings.

PARTS NUMBERS

When ordnance parts are identified through the useof the IPB, ordnance drawings, or from part ofmanufacturer’s numbers stamped on the parts, an NSNfor each part is required before the parts can be

requisitioned. These NSNs are listed in the COSAL thathas across-reference section that converts apart numberto an NSN.

The COSAL establishes the shipboard allowancefor installed and portable equipment, equipage, andsupporting material. Each COSAL is prepared for anindividual ship and enables that ship to have a maximumself-supporting capability for an extended period oftime.

Ships are issued a separate COSAL for eachcategory of material. The index to all COSALs is issuedby the Naval Supply Systems Command. Normally, onecopy of the ordnance COSAL is kept by the supplydepartment and one copy by the weapons or combatsystems department,

If an NSN for a part cannot be found, the part canbe requisitioned by the drawing and piece number andany other identification, such as the equipment’s markand mod, the manufacturer’s name, the amperage andvoltage rating, the name of electrical parts, and the serialnumber of the major unit from which the part wasremoved. Additional information about apart can alsobe obtained from equipment IPBs.

COMMON MAINTENANCEPROCEDURES

LEARNING OBJECTIVES: Discuss hydraulicand mechanical maintenance procedures, sealreplacement, and special tools used on navalgun systems.

Traditionally, some of the most common preventivemaintenance procedures have had to be learned by themaintenance person on the job. This is the case withreplacing hydraulic seals and making mechanicaladjustments. In this section we will provide you withsome insight into the performance of these procedures.It maybe helpful to have the maintenance manuals foryour system handy to refer to as we go through theseprocedures. In all cases, you must consider the systemmaintenance manuals and maintenance requirementcards (MRCs) as your primary source of guidance andinformation. The information provided here is intendedto augment and clarify these manuals.

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HYDRAULIC SEAL REPLACEMENT Types of Seals

Most modern gun systems are loaded andpositioned by hydraulic machinery. System pressures,in many cases, exceed 1,000 pounds per square inch(psi). As a Gunner’s Mate performing routinemaintenance on your gun, you need to be constantly onthe lookout for hydraulic fluid leaking past the sealsaround pistons and operating shafts. When your systemis leaking, it is telling you something. The seals arebreaking down or are worn and could rupture at anytime. Should the packings around a large high-pressurepiston fail, you could dump 10 or 15 gallons of hydraulicfluid before the system can be secured. All leaks needto be reported, documented, and repaired as soon aspossible.

Leak Documentation

When a leak is first discovered, it should be reportedto your leading petty officer (LPO) and/or work centersupervisor (WCS). Normally as the maintenanceperson, you will also be required to document the leakusing the ship’s 3-M Systems, Form 4790-2K. In thewrite-up, it is important to use proper terminology indescribing the exact location and component where theleak exists. In describing what is required to correct theproblem, it is helpful to include the part number andquantity of seals and other repair parts needed to do thejob. Component names and part numbers are found inthe IPB. Providing an exact description of the problemand the parts required to effect the repair serves twopurposes. If, for some reason, you are not available tohelp when the repair is scheduled, other maintenancepersonnel will be able to identify the problem and itssolution easily. Second, when a problem isdocumented, it is incorporated into the Current Ship’sMaintenance Project (CSMP). The CSMP providesNavy managers at all levels with informationconcerning the readiness of the systems aboard ships. Itis used to plan and coordinate maintenance actions inthe work center and to put together overhaul packagesfor completion by tenders and shipyards.

This documentation procedure not only applies tohydraulic leaks but to all other corrective maintenanceyou will perform. It is not normally necessary todocument routine mechanical adjustments. However, ifthe adjustment is necessary due to replacement of adamaged or worn component, the circumstancessurrounding the component replacement should berecorded.

Before we go into the actual repair process, we needto describe some of the common types of seals used inordnance equipment. A normal high-pressure packingconsists of a U-Cup seal and a wiper ring. The U-Cupseal is installed with the cup facing the pressure it is tocontain. As hydraulic pressure is applied, the cup fallsand the sealing edge is held against the shaft or pistonsurface. The wiper ring keeps the piston surface cleanto prevent wear of the U-Cup seal. These seals are oftencontained in an insert, called a packing gland, that isbolted or screwed into a valve block or cylinder. Thepacking gland allows for easy replacement of the sealssince it can be removed. Figure 12-8 shows these sealsand how they are installed in an actual valve block TheU-Cup seal is contained in a machined groove on theinside surface of the packing gland. The wiper ring isinstalled into another machined groove at the outsideedge of the gland. Note the rubber O-ring seal in themachined groove around the outside of the packinggland. Since both are machined to very closedimensions, an O ring is sufficient to contain anyseepage that may occur. O rings are used throughoutordnance equipment in low-pressure sealingapplications.

Figure 12-8.—A typical high-pressure hydraulic seal.

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Another type of seal you may encounter is theencased seal (fig. 12-9). This type of seal is found whererotating shafts exit gearcases or other fluid-filledreservoirs. As the name implies, the seal is encased ina metal housing. Sealing surface tension around therotating shaft is maintained by a spring located underthe lip of the seal. The metal case of the seal allows itto be pressed into the component casing.

Seal Replacement

In replacing hydraulic system seals, you must takecare not to contaminate the system. Contaminates in ahydraulic system can have devastating effects. Damagecan range from accelerated seal wear to the totaldestruction of pumps, valves, and drive units. Usingsome simple precautions can help make sure yoursystem remains free from contamination. First, makesure the area around the component you are going todisassemble is thoroughly cleaned Second, after acomponent is removed, coverall exposed openings intothe system with rags. Components removed for accesscan be reinstalled with their bolts turned finger tight.Reinstalling components and their retaining bolts alsohelps you to keep track of them. Last, make sure thecomponent and the area it is to be reinstalled into arethoroughly cleaned. Anything you can do to limithydraulic system exposure to outside conditions willhelp you maintain a system free of contamination.

Seal replacement often requires the use of specialtools. A good example of this is the tool used to reinstallthe packing gland over the end of the recoil piston (fig.12-10). The tool is in the form of a ring, tapered on theoutside, that is slid over the threaded end of the recoilpiston and up against the squared end of the enlargedsection of the piston. The tapered outside of the toolallows the sealing surface of the U-Cup seal, which isfitted into a machined groove inside the packing gland,to slide easily past the squared end of the enlargedsection of the recoil piston. The disassembly andreassembly of major gun system components aredescribed in the system maintenance manual. Anyspecial tools needed are identified throughout theprocedure as required. All gun mount special tools areillustrated and described in the system maintenancemanual.

Figure 12-9.—Encased seal.

Figure 12-10.—Use of a hydraulic seal replacement specialtool.

The disassembly of hydraulic equipment inevitablycauses air to get into the system. Your system will befitted with vent plugs for releasing this air. Air iscompressible and can cause your system to operateerratically or sluggishly. Be sure to follow the detailedinstructions found in your systems maintenance manualor the appropriate MRC for venting air from thehydraulic system.

You may also find it necessary to replenish yoursystem with hydraulic fluid after a repair is completed.The procedure for adding fluid to the system can befound both in the system maintenance manual and on asituation requirement (R) MRC. You will normallyfollow the procedure described on the MRC. Additionalinformation on seals and seal replacement can be foundin Fluid Power, NAVEDTRA 12964.

MECHANICAL ADJUSTMENTS

Gun loading system hydraulic machinery useshydraulic pressure to position mechanical devices thatmove rounds of ammunition through the system forfiring. Almost without exception, these mechanicaldevices must be adjusted to maintain travel andproximity tolerances to ensure proper performance.Some adjustments are verified during routinemaintenance as part of the procedure contained on anMRC. Most often, however, you will need to makeadjustments to mechanical equipment after it has beendisassembled, repaired, and reassembled. Such is thecase, for example, after a linkage has been removed toget to a hydraulic packing that required replacement orafter a damaged component has been removed andreplaced You must refer to the system maintenancemanual to determine the exact procedure and tolerancesbefore making any mechanical adjustments. With this

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in mind, we will now provide you with some generalinformation on the different types of mechanicaladjustments found on gun mounts.

Clevis

The most common mechanical adjustment involvesa threaded linkage that is screwed into or out of anothercomponent to adjust its travel or proximity to othercomponents. Most mechanical linkages are connectedto each other and to the components they control oroperate with a clevis (fig. 12-11). A clevis is a U-shapedpiece of metal with holes through the ends where a pinis inserted to attach one thing to another. The clevis isused as a flexible connection for mechanical linkages.It can be adjustable or nonadjustable and is oftenrefereed to as a yoke. The adjustable clevis may beeither threaded through the base to allow for theinsertion of a threaded shaft or it can be manufacturedto include a threaded shaft. Often, the twoconfigurations are used together as opposite ends of anadjustable linkage.

Threaded Shaft

Another common mechanical adjustment consistsof an operating shaft threaded in one or both ends. Aconnecting shaft or actuator is screwed in or out of thesethreaded ends to adjust its travel or proximity to anothercomponent. This configuration can be used to adjustcam followers and mechanical actuators that push orpull a component to cause its operation (fig. 12-12).

Figure 12-11.—The clevis. Figure 12-12.—Threaded linkage adjustments.

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Figure 12-13.—Eccentric shaft.

Eccentric Shaft

In some special instances a mechanical adjustmentmay involve shifting the rotational axis of a pivotingcomponent. This is accomplished through the use of aneccentric shaft. An eccentric shaft, as shown in figure12-13, is an otherwise straight shaft with an offset diskin the middle. The offset disk is the rotational axis of apivoting component. Being offset, it allows this axis tobe adjusted simply by rotating the shaft. In some cases,the eccentric shaft may be used as an adjustable securingpin instead of a pivot point.

Shims

Some gun mount adjustments are accomplishedusing shims. This is often the case when a majorcomponent is replaced and must be “fitted intoalignment or proximity with surrounding components.A shim is a noncompressible material, in sheet form, thatis inserted between two components that are boltedtogether. Shim material is available in a standard packof three different dimensions that can be cut and addedtogether to achieve the desired thickness.

Hydraulic and mechanical maintenance is at thecore of the traditional work of the Gunner’s Mate.Mastery of hydraulic and mechanical maintenance,along with proficiency in troubleshooting electroniccontrol circuits (chapter 5), is the definingcharacteristics of your expertise as a Gunner’s Mate.

DAMAGE CONTROL PMS

LEARNING OBJECTIVES: Discuss theimportance of divisional damage control onnaval ships.

A common attitude throughout the fleet is thatdamage control (DC) is the responsibility of theengineers. As a result, the material condition of a shipfrequently deteriorates due to a lack of attention todamage control maintenance at the various levels ofperformance. In fact, DC is an all-hands responsibilityand should be performed and managed as such. What’sthe value of having a gun or radar working at 100 percen”capacity if the ship is already sinking?

A large amount of DC maintenance, such asweighing fire extinguishers or checking the operabilityof battle lanterns, are considered to be routine tasks andcan be accomplished by just about anyone. Figure12-14 shows atypical organizational structure of the DCPMS program aboard ship. As shown, a senior HullTechnician/Damage Controlman serves as the

Figure 12-14.—Representative organizational structure for damage control PMS.

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shipboard damage control work center supervisor. Eachdivision assigns a damage control petty officer (DCPO)to the DC work center. The DCPO then performs theroutine maintenance on the DC equipment located in hisor her division spaces as assigned by the DC work centersupervisor.

PMS schedules for DC are kept in nearly the samemanner as regular PMS schedules and are maintainedfor the entire ship by the DC work center supervisor.Individual weekly schedules may also be maintained bythe DCPO within his or her spaces in the division. Sincethe quarterly schedule lists each division assigned toperform DC PMS, it will not match the cycle scheduleline for line.

Scheduling instructions for DC PMS is located inchapter 5 of OPNAVINST 4790.4. Shipboard damagecontrol organization and requirements are outlined inSurface Ship Damage Control, NWP 62-1.

PMS MANAGEMENT

LEARNING OBJECTIVES: Discuss theimportance of PMS management at shipboardand type commander levels, and the definitionsused to evaluate the PMS program.

One of the most important considerations in theoperation of a PMS program is the proper managementof that program at all levels concerned.

SHIPBOARD EVALUATION OF PMS

To have an effective maintenance program, youshould be involved at all levels of management aboardship in the supervision and evaluation of PMS. It canbe safely said that every officer and most chief pettyofficers will be tasked with evaluating theaccomplishment of PMS aboard their ship. A typicalexample of the structure of the 3-M organization aboard

Figure 12-15.—Shipboard 3-M Systems organization.

ship is shown in figure 12-15. As you can see, themajority of senior shipboard personnel are involvedwith PMS functions.

One of the best ways to evaluate the effectivenessof shipboard PMS is by conducting spot checks ofindividual maintenance requirements. As the leadingGM, you may often be tasked with performing a spotcheck on a work center outside of your department.Table 12-2 identifies the minimum shipboard spot checkrequirements, who they should be accomplished by, andthe periodicity at which they should be conducted.

The maintenance prescribed in the PMS package isdefined as the minimum required. Therefore, amaintenance requirement that has been deferred beyondits assigned periodicity is not considered to beaccomplished. These deferrals will affect the

Table 12-2.—Minimum PMS Spot Check Requirements and Periodicity of Accomplishment

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accomplishment rate of the PMS of the work center andshould be kept to a minimum. The work group or workcenter supervisor should know at all times whatmaintenance requirements have been deferred and forwhat reason(s).

TYPE COMMANDER EVALUATION OFPMS

In addition to shipboard evaluation, typecommanders (TYCOMs) are also tasked withmonitoring the effective management of PMS withintheir respective commands. The TYCOM conductsPMS inspections at periods of 18 to 24 months, usinghis or her own qualified inspectors, working inconjunction with the ship’s 3-M coordinator and othershipboard managers as required. These inspections areconducted on a “no advance notice” basis. A PMSPerformance Rate (PPR) of less than 75 percent is afailing grade and will definitely bring down somehigh-powered attention from such people as yoursquadron or group commander.

To ensure standardization for the measurement ofPMS performance, you should use the followingdefinitions to evaluate PMS performance:

PPR—(PMS Performance Rate). This is anoverall quantitative evaluation of the actualperformance of the required maintenance plannedfor accomplishment.

RAR-—(PMS Recorded Accomplishment Rate).This is the percentage of maintenance scheduledduring the period of examination that is recorded asaccomplished.

ACF—(PMS Accomplishment ConfidenceFactor). This is the percentage of maintenancerecorded as accomplished that is evaluated asactually having been performed.

A— This is the symbol that identifies thenumber of maintenance requirements actuallyscheduled. It is used to compute the RAR.

B— 1 This is the symbol for the number ofmaintenance requirements recorded as fullyaccomplished. It is also used in computing theRAR.

C— This is the symbol for the number ofpartials and is the final factor required tocompute the RAR.

N— This is the symbol for the number ofmaintenance requirements evaluated by the

inspector as not accomplished. It is used tocompute the ACF.

P— This is the symbol for the number ofmaintenance requirements evaluated by theinspector as having been partiallyaccomplished. It also is required to computethe ACF.

S— This symbol represents the number ofmaintenance requirements sampled by theinspector and is the final factor required tocompute the ACF.

The ship’s final grade is determined by computationof its PMS Performance Rate (PPR) as follows:

First, you must determine the RAR by using thefollowing formula:

Second, determine ACF by using the formula

Now you can determine your PPR by using theformula

This system may seem complicated but is actuallysimple once you have learned to use it. You can use itto monitor your accomplishment rate, as well as toidentify problem areas within your ship’s PMS program.Detailed instructions on PMS inspections and theirprocedures are located in chapter 5 of OPNAVINST4790.4.

QUALITY ASSURANCE

LEARNING OBJECTIVES: Discuss thequality assurance program, its importance, andresponsibilities of the Gunner’s Mate withrespect to naval ordnance.

The Quality Assurance (QA) program is designedto provide the fleet with safe ordnance material of thehighest quality in a timely manner. The basic prioritiesare safety first, quality second, and quantity third. Theprogram is conducted when the material is acquiredfrom the contractors and during receipt, production,

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maintenance, stowage, and issue of ordnance materialat naval activities.

Quality assurance requirements and proceduresensure that:

1. Incoming ordnance material is of the designatedtype and quality; has not been damaged in shipment; isidentified with the appropriate condition code status(serviceable, unserviceable, suspended, etc.); and ispacked, packaged, and preserved as necessary. This willpermit further processing in a safe manner and aid in theprevention of material damage or deterioration duringstowage, handling, and issue.

2. Ordnance material is segregated into compatiblegroups by explosive content and condition code forstowage, further processing, or transshipment.

3. Ordnance material is controlled during handlingand stowage to prevent the existence of unsafeconditions or degradation of serviceable material.

4. Periodic maintenance is performed as requiredand maintenance and renovation operations arecontrolled to ensure that ordnance material completingthese operations conforms to all applicable specificationrequirements.

5. Only safe and serviceable ordnance material isissued to operational units.

6. Ordnance material destined for outload ispacked, packaged, and preserved as specified inapplicable technical documents and, after loading, issecurely blocked, braced, and dunnaged in the carrier tofacilitate safe transport.

ORGANIZATION AND RESPONSIBILITIES

The commanding officer of an activity has finalresponsibility for the quality of issued ordnancematerial. Weapons and ordnance personnel areresponsible for ensuring the quality of ordnancematerial to be issued and for maintaining control ofordnance material throughout activity operations. Thequality assurance organization within a command isresponsible for providing assurance that the necessarycontrols are established and maintained and thatordnance material being issued meets specified qualityrequirements.

A quality assurance organizational elementresponsible for performing quality assurance functionson ordnance material is required at each activity. Thisquality assurance element must be established at a levelthat provides the organizational independence

necessary to achieve full implementation of qualityassurance procedures. Each activity must plan,establish, staff, and maintain the ordnance qualityassurance organization commensurate with local workload. The head of quality assurance serves as thecommanding officer’s representative and reportsdirectly to the CO.

At ordnance-oriented activities, such as navalmagazines and naval ordnance facilities or navalstations, the ordnance quality assurance organizationshould be established as a division within theweapons/ordnance office. Another alternative at thesetypes of activities is to include the ordnance qualityassurance organization as a division within the QAdepartment of the activity, along with quality assuranceorganizations for other programs.

Each division within the QA department must bedivided into branches as necessary to perform therequired QA functions effectively.

The head of an ordnance QA organization ashoremay be military or civilian. However, it is essential thatthis person be well-qualified in ordnance QAprocedures, methods, and techniques, in addition tobeing knowledgeable in the technical aspects of thespecific ordnance material being processed. In anyevent, the individual must have the ability to plan andmanage the ordnance quality assurance functions andtrain subordinate personnel as required. Collateralnonquality assurance functions assigned to the ordnanceQA organization should be kept to a minimum. This isnecessary to avoid detracting from the essentialordnance QA functions. Subordinate personnel mustalso have a good working knowledge of both thetechnical aspects of the material and ordnance QAprocedures.

In some cases, because of budgetary, manpower, orother limitations, it may not be possible to establish aseparate quality organization. In this case, qualifiedpersonnel from within the activity must be selected andtrained to perform the QA functions. Such personnelshould be permitted to perform the assigned QAfunctions without undue external pressure, the bias ofinspecting their own work, and being held responsiblefor delays in production.

The weapons department should have an ordnanceindoctrination/training program. The QA organizationshould provide the materials for the quality assurancesegment of the indoctrination/training. The QAsegment of the indoctrination maybe accomplished by

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QA personnel or through normal activity trainingprogram procedures.

A list of military and civilian personnel whose workassignments may directly affect the quality of ordnancematerial must be compiled and the personnel scheduledinto the indoctrination/training program. Newpersonnel destined to perform work related to ordnancematerial should be scheduled into the indoctrination/training program as they arrive on station. Weaponssupervisory personnel and QA personnel must beconstantly alert to the need for refresher training or otherspecific ordnance-related training requirements asevidenced by the quality of work performed. Weaponssupervisors will ensure that the necessary on-the-jobtraining (OJT) or classroom training is provided beforeassigning personnel to new jobs related to ordnancematerial processing. Records of OJT and classroomtraining for weapons personnel must be prepared andmaintained.

The head of the QA organization will schedule allpersonnel who will be assigned to perform QA functionsinto training in the content and application of the qualityassurance procedures.

Each supervisor will provide OJT throughrotational work assignments to provide increased rangeand depth to the capability of QA personnel. Theseperiods of OJT should be of a sufficient duration toensure that the trainee is fully qualified to perform hisor her duties in that area of assignment.

CALIBRATION OF TEST ANDMEASURING EQUIPMENT

QA must ensure that only currently calibrated testand measuring equipment is used to record or generatequantitative measurements or data during maintenanceactions. Each QA inspector should verify thatcalibration labels and tags are affixed to all test andmeasuring equipment within his or her work area. Thelabels and tags must indicate that the equipment is in an“in-calibration” status or does not require calibration.Any discrepancies noted should be documented.

QA personnel should perform daily monitoringwithin each work area to ensure that only those gaugesauthorized for use by the ordnance work instructions arebeing used or are available for use by weaponspersonnel and that the gauges display current evidenceof calibration. During these daily monitoring actions,QA should verify that all activity organizationalelements properly use, handle, and stow these gauges.

QUALITY DEFICIENCYREPORTING

Information feedback is needed for correctiveaction purposes when deficiencies are found in materialreceived as serviceable (RFI) from other activities orfrom the supply system. NAVMATINST 4855.8establishes a DoD system for reporting qualitydeficiency data and provides the reporting proceduresand forms for this purpose.

Quality deficiency reports are submitted to ascreening point within the activity originating the report.Here, the responsible action point (activity responsiblefor resolution of the deficiency) is determined and thereport is forwarded to that action point. Completeinstructions on quality deficiency reporting arecontained in NAVMATINST 4855.8. Only Category Ireports will be addressed in this text.

A Category I report is submitted when a deficiencyis found that might affect life or limb of personnel orimpair the combat capabilities of the using organizationor individual. Deficiencies that affect an operationalcapability to the extent that accomplishment of themission is jeopardized are included in Category I.

Category I reports must be submitted by message.When urgency dictates, reports may first be transmittedby the most expeditious means available (e.g., telephoneor local visits). Oral communications must beconfirmed by a message. Information copies ofCategory I reports may be submitted to any activityconsidered necessary to alert them to the problem.

The originator of the Category I report mustforward the report to the designated screening pointwithin 24 hours after discovery of the deficiency.The report must be screened for completeness andaccuracy and forwarded to the appropriate actionpoint within 48 hours after receipt. The component oractivity responsible for action must acknowledgereceipt of each report to the screening activity within 24hours.

SAFETY

LEARNING OBJECTIVES: Discuss theimportance of observing proper safetyprocedures when working on naval gun systemsand ordnance.

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The primary reason for the vast amount ofinformation available on the subject of safetyprecautions is simply the desire to prevent accidents.Research has shown that a majority of all accidents cameabout through sheer carelessness. Not only is there aloss of time involved in an accident but there is also anaccompanying loss of equipment, material, or, in theextreme case, life itself. Aside from these importantconsiderations, there is a vast amount of money wastedin replacing damaged equipment, making investiga-tions, paying for hospitalization or funerals, and forman-hours not worked during convalescence. These arebut a few of the problems faced everyday by the Navybecause personnel fail to heed the posted and requiredsafety precautions.

Safety is everybody’s job. Awareness of danger,knowledge of how to avoid it, and constant vigilance arethe three basic requirements for the prevention ofaccidents while you are working on or operatingordnance equipment.

Safety is both a result and a reflection of goodtraining. The crews of a gun mount maybe trained sothat they know how to do their jobs; however, the crewstill cannot be considered well trained unless each ofthem is safety conscious. Safe working habits must beimpressed upon every crew member through properinstructions, constant drills, and continuoussupervision. Carelessness, cockiness, and lack oftraining have led to disaster while working with all typesof ordnance equipment and materials.

Practical safety features are incorporated into Navyequipment to eliminate potential hazards to personnel.Since familiarity with equipment leads to carelessness,observation of all safety notices and rules is mandatory.No relaxation of vigilance should ever be permitted.

Each piece of ordnance equipment has a specific listof safety precautions to be observed during operationand/or maintenance. Study these thoroughly beforeattempting to operate or repair any piece of equipmentthat you are not familiar with.

The following safety rules are but a few of the manythat must be observed when operating or working onhydraulic or pneumatic systems:

Never disconnect hydraulic lines or disassemblehydraulic equipment when the hydraulic system powermotor is running.

Never disconnect hydraulic lines or disassemblyhydraulic equipment until the accumulators have beenmanually dumped to the tank.

Never manually actuate switches, solenoids,relays, or valves on hydraulic systems under pressureunless you are competent and qualified to perform theseactions.

Report hydraulic leaks immediately so that theymay be repaired at the first opportunity.

If clothing becomes drenched with hydraulicfluid, immediately change into dry clothing. Hydraulicfluid is injurious to health when in prolonged contactwith the skin. It is also a fire hazard. Immediately wipeup all spilled fluid.

Do not direct a high-pressure air jet at any part ofthe human body; this may be fatal.

All personnel taking part in and observing operationof power equipment must remain alert, keep clear ofmoving parts, and be thoroughly familiar with the safetyprecautions applicable to that equipment. At no timeshould skylarking be allowed in the vicinity of operatingpower equipment.

Hydraulic systems operate under hydraulicpressures ranging from approximately 100 psi to 2,000psi. Some pneumatic systems operate in approximatelythe same range of pressures as hydraulics. Thesepressures are dangerous and can be hazardous topersonnel.

Safety precautions must be observed whenperforming maintenance, testing, and operatingordnance hydraulic and pneumatic equipment. Thehigh-pressure liquid or air can cause major injuries toyour face, hands, and other parts of the body by jets ofair or liquid escaping from valves or pipe connectionsthat are highly pressurized.

The following summary of safety precautions isintended to be general in nature, but its importanceshould not be misunderstood:

Do not service or adjust live equipment withoutthe presence of another person capable of rendering firstaid.

Never measure potentials over 600 volts bymeans of flexible test leads.

Do not tamper with interlocks or any otherequipment safety feature.

If possible, use only one hand when working onlive circuits.

Never use electrical or electronic equipmentknown to be in poor condition.

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Do not allow unqualified personnel to operate thecontrol panels. Trainees or other persons undergoinginstructions should be allowed to operate control panelsonly under the strict supervision of a qualified andresponsible operator.

Except for general quarters, always sound thetrain warning bell and get an all-clear signal beforetraining and/or elevating the gun mount (before eachtime the equipment is to be moved).

Whenever any power drive unit that is capable ofinflicting injury to personnel or material notcontinuously visible to the person controlling suchmotion is moved, the officer or petty officer authorizingthe unit to be moved by power must ensure a safetywatch. The on-deck safety watch is not necessaryduring general quarters but must be maintained in areaswhere such injury is possible, both inside and outsidethe unit being moved. There should be a telephone orother effective voice communications established andmaintained between the station controlling the unit andthe safety watch.

The following are a few basic rules that you shouldkeep in mind when using wrenches:

Always use a wrench that fits the nut properly.

Keep wrenches clean and free from oil.Otherwise, they may slip, resulting in possible seriousinjury to you or damage to the work.

Do not increase the leverage of a wrench byplacing a pipe over the handle. Increased leverage maydamage the wrench or the work.

Provide some sort of kit or case for all wrenches.Return them to it at the completion of each job. Thissaves time and trouble and facilitates selection of toolsfor the next job. Most important, it eliminates thepossibility of leaving them where they can cause injuryor damage to personnel or equipment.

Determine which way a nut should be turnedbefore trying to loosen it. Most nuts are turnedcounterclockwise for removal. This may seem obvious,but even experienced personnel have been observedstraining at the wrench in the tightening direction whenthey wanted to loosen it.

Learn to select your wrenches to fit the type ofwork you are doing. If you are not familiar with thesewrenches, make arrangements to visit a shop that hasmost of them and get acquainted.

The following precautions should be observedwhen using torque wrenches:

Do not use the torque wrench as a hammer.

When using the micrometer-setting type, do notmove the setting handle below the lowest torque setting.However, it should be placed at its lowest setting beforebeing stowed.

Do not use the torque wrench to apply greateramounts of torque than its rated capacity.

Do not use the torque wrench to break loose boltsthat have been previously tightened.

Never stow a torque wrench in a toolbox or in anarea where it maybe damaged.

Be thoroughly familiar with all posted safetyprecautions and those listed in the OP pertaining to theequipment to which you are assigned.

Do not think that once you have learned allapplicable safety precautions you can sit back and takethings easy. Review the precautions periodically,particularly those for jobs seldom performed. Try toimprove upon any rules in effect. Safety is everyone’sresponsibility, not just those who developed theregulations. Most accidents are caused by personnelwho are so familiar with their job they think they cantake shortcuts; by personnel who do not know theapplicable precautions; by practical jokers; or, in themajority of instances, by plain carelessness.

PMS SAFETY

As in all other evolutions, the observance of propersafety procedures is also an important considerationwhen performing PMS. It is extremely important thatpersonnel involved in maintenance are thoroughlytrained in safety practices. Nothing can replace goodcommon sense when performing any kind of task, butawareness of the specific hazards of a given job will savelives and prevent damage to equipment. MaintenanceRequirement Cards (MRCs) have warnings andcautions inserted immediately before the proceduralstep they apply to and should be obeyed as closely aspossible. Any discrepancies or inadequacies in PMSsafety procedures should be reported immediately viaan urgent PMS Feedback Report. Navy SafetyPrecautions for Forces Afloat (OPNAVINST 5100)contains safety instructions and precautions to be usedwhen performing PMS.

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SPECIAL SAFETY MARKINGS

Index marks and safety lines are painted on or nearordnance equipment and are used by the GM to indicatea complete mechanical function and to indicate safeareas.

An example of the index mark is the breech-closedindex painted on the gun housing (fig. 12-16). Theindex mark shows at once whether the breechblock risespromptly to full breech-closed position, or is sluggish,or sticks. Some guns also have index marks on thehousing and slide to indicate full return to the battery.These index marks tend to wear off and requireperiodical freshening up. Be careful not to get the painton any other part of the sliding surfaces.

Safety lines mark off safe working areas. Circularsafety lines are painted on the deck around a gun mountto indicate the areas you should stay out of when the gunis being trained. “Blast area” lines are painted on thedecks around rocket launchers to show how far awayyou must get to be safe from the hot-rocket blasts.Similar safety lines are necessary to show safe workingareas around overhead conveyors and other machinesthat may be dangerous to personnel who fail to keepaway from working parts.

SUMMARY

Gun maintenance involves a wide variety of skillsand knowledge. However, all of the skill andknowledge in the world are useless without a highdegree of personal dedication to your job and the peoplearound you. The dangers involved in gunnery arereadily apparent. Your vigilance as a maintenancetechnician may well make the difference between asuccessful gunshoot or missile launch and a catastrophic

Figure 12-16.—Breech-closed index mark.

accident. Take the time to learn your system and neverassume anything.

In this chapter we have discussed the variousmaintenance requirements involved in keeping a gunand missile system operational. We described theimportant foundational role preventive maintenanceplays in both system readiness and your personaldevelopment as a technician. We described thelubricants and tools used in routine maintenance as wellas the reference publications that provide in-depthinformation about the operation, upkeep, and repair ofyour gun or launcher. We described some specificmaintenance actions that you will be involved in, suchas barrel maintenance, replacement of hydraulic seals,and mechanical adjustments. We also discussed somemaintenance-related safety precautions. We concludedwith a brief discussion of PMS, quality assurance, andsafety.

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