CHAPTER 11

ALIGNMENT

For any weapon system to be effective, thedestructive device must be delivered to the targetaccurately. Many air targets are now capable of speedsfaster than sound; therefore, they must be detected andengaged at greater distances. Technologicalimprovements in modern weapons systems require thatequal improvements be made in their associateddetection and fire control systems. Proper batteryalignment is a must if ordnance is to be delivered ontarget.

In this chapter we will describe the basicfundamentals of alignment principles and batteryalignment. We will also discuss firing cutoutmechanisms, radar alignment, and the final alignmentand test.

ALIGNMENT PRINCIPLES

LEARNING OBJECTIVES: Descr ibealignment principles and procedures on navalgun systems.

The elements of a modern combat system mustwork together with a great degree of accuracy to deliverordnance on target. All are electrical y and/ormechanically linked to pass data from one unit to thenext. Each equipment with alignable properties must bealigned to a common reference to ensure a correctexchange of data between the various systems. Datatransmission and response synchros must be properlyzeroed. All gun bores, missile launchers, fire controldirectors, radar antennas, gyrocompasses, and othersimilar pointing lines must be parallel (when no parallaxor ballistic corrections have been made). Combatsystem alignment is the process of establishingparallelism, within acceptable tolerances, between theelements of the combat system.

In this section we will describe the sequence usedin establishing combat system alignment. Followingthat, we will discuss the more familiar sequence ofalignment verification.

SEQUENCE OF ALIGNMENT

Combat system alignment begins with the design ofthe ship. Alignment is established as the ship isconstructed. Once constructed, alignment iscontinually perfected up to the point where the ship isplaced in commission and its permanent operationalcrew is on board. As a ship goes through its normal lifecycle, it is the job of the crew to verify this alignmentcontinually, making corrections as necessary.

Certain steps in a combat system alignment processmust be accomplished according to a specifiedsequence. The sequential steps are as follows:

1.

2.

3.

4.

5.

6.

7.

Establishment of reference planes

Establishment of reference marks

Establishment of parallelism

Performance of fire control radar radiofrequency (RF)—optical alignment

Performance of train and elevation alignment

Establishment of benchmark and tram referencereadings

Performance of dynamic train alignment

Establishment of Reference Planes

The first major alignment step is the establishmentof reference planes. A position can only be describedby relating it to a known reference point. Referenceplanes allow combat system elements to be described asto how they are situated in relationship to each other.Reference planes are established during the initialconstruction of the ship and are used as required duringalignment of the combat system. Reference planesconsist of the center-line reference plane (CRP), the shipbase plane (SBP), the master reference plane (MRP),and the weapons control reference plane (WCRP).

CENTER-LINE REFERENCE PLANE.— Thecenter-line reference plane (CRP) is the first planeestablished. It is the plane containing the ship’s centerline and is perpendicular to the SBP. The CRP is thereference used to establish the train zero alignment ofall of the combat system equipment.

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SHIPBASE PLANE.— The shipbase plane (SBP),the basic plane of origin, is perpendicular to the CRPand includes the base line of the ship, but is notnecessarily parallel to the keel.

MASTER REFERENCE PLANE.— The masterreference plane (MRP) is a plane within the ship parallelto the SBP. On most ships, the MRP is represented bya master level plate that has been accurately leveled tothe SBP and aligned in bearing to the CRP. The MRP isused as the machining reference to establish thefoundations of the combat system equipment. Afterinitial construction alignment, the MRP is only used asa reference plane following major damage ormodernization.

W E A P O N C O N T R O L R E F E R E N C EPLANE.— The weapon control reference plane(WCRP) is established during initial construction and isusually represented by the roller path plane (RPP) or theequipment that has been designated the alignmentreference. This is the plane, which most people arefamiliar with, that is involved with alignmentverification. On the FFG-7 class ship, for example, theWCRP is the roller path of the Mk 75 gun mount.

Establishment of Reference Marks

The second major alignment step is theestablishment of reference marks. Reference marksinclude center-line reference marks, offset center-linereference marks, and equipment bench marks.

CENTER-LINE REFERENCE MARKS.—Center-line reference marks are established duringinitial construction to represent the ship’s center line.Several small plates (at least two forward and two aft)will be installed at intervals along the center line toindicate its location.

OFFSET CENTER-LINE REFERENCEMARKS.— Offset center-line reference marks are alsoestablished during initial construction to facilitate thecombat system alignment. The offset center line isestablished parallel or perpendicular to the ship’s centerline. These marks are installed to prevent repeating thecenter-line survey during subsequent alignments. Theymust be maintained within 1 minute of arc of the CRP.

BENCH MARKS.— Bench marks are the mostfamiliar of all the reference marks to the averageequipment operator/maintenance person. A bench markis installed for each equipment that has an alignmenttelescope. Bench marks are installed at any convenientlocation that is visible through the equipment telescope.

Equipment bench marks are used throughout the life ofthe ship to verify alignment.

Establishment of Parallelism

The third major alignment step is the establishmentof parallelism between the roller path planes (RPPs) ofaIl the equipment in the combat system. This step is alsoaccomplished during initial construction. It isaccomplished again as new systems are added or oldequipment is replaced. The steps necessary to achievethe required degree of parallelism are foundationmachining, inclination verification, and interequipmentleveling.

FOUNDATION MACHINING.— Before thecombat system equipment is installed aboard ship, theequipment foundations are machined so that the planesof the foundations are parallel, within tolerance, to thereference plane and then smoothed to the requiredflatness.

When the equipment is mounted aboard ship, theRPPs will not be precisely parallel. It is not possibleunder normal conditions to attain perfect accuracy inmachining or in the construction of equipment. Therewill always be some error. However, once machinedwithin tolerance, there are devices incorporated intomost equipment that can be adjusted to compensate forroller path alignment error. These devices are discussedlater.

INCLINATION VERIFICATION.— Inclinationverification consists of the measurement of the tiltbetween equipment RPPs of the equipment in thecombat system and the reference plane. Figure 11-1shows a plane tilted with respect to the reference plane.Note that the inclination varies with the bearing. In thedirection of line OA, the inclination is zero. Inclinationincreases gradually in the direction of line OB until itreaches maximum positive angle at 90° from line OA.Point B is the bearing of the high point (Bhp). Point Dis a negative angle, proportionate to the positive angleof point B. All the references to roller path alignmentare expressed in terms of the bearing and inclination ofthe high point. The tilt of the RPP is determined by usingclinometers or similar devices.

INTEREQUIPMENT LEVELING.— YOU canaccomplish equipment leveling through the use ofleveling rings, shims, adjusting screws, equipmentadjustments, or offset by software.

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Figure 11-1.—Variation of roller path inclination with bearing.

A common device used to offset the effects ofroller path misalignment is the roller pathcompensator. The roller path compensator isincorporated into the elevation receiver-regulatorof most gun mounts. It is connected through gearsand linkages to the train drive unit. The rollerpath compensator is set with the bearing andmagnitude (in minutes) of the high point. As thegun moves in train, the compensator is moved andeither adds or subtracts from the elevation order thenumber of minutes necessary to cancel out theroller path error at that bearing. For furtherinformation on roller path alignment, see NAVSEAOP-762, chapter 5.

Performance of Fire Control RadarRF-Optical Alignment

The fourth major alignment step is the verificationof fire control RF-optical alignment (collimation). Thisis the alignment between the axis of the RF energy beamemitted by the fire control radar and an optical deviceattached to the radar antenna. During initial installation,the alignment is established and the optics are securedin place. During subsequent alignment checks, you canmake adjustments to correct any errors detected. Radarcollimation checks are normally conducted using acertified shore tower facility. Some radars, however,may be collimated while tracking a target. Figure 11-2shows the essence of radar collimation.

Figure 11-2.—Radar collimation.

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Performance of Train and Elevation Alignment

The fifth major alignment step is the performanceof train and elevation alignment. This alignment isperformed by fleet support personnel to make sure thepointing lines are parallel. This procedure is the sameone performed by fleet personnel to verify systemalignment. Two procedures can be used for train andelevation alignment. The first is the establishment oftrain and elevation zero (theodolite method); the secondis the train and elevation space alignment (star checkmethod).

The theodolite method aligns train zero to thecenter-line reference plane and elevation zero to theroller path plane of the equipment. The more familiarstar check method establishes parallelism betweencombat system elements by having them all sight on acelestial body, then aligning their dials to match thoseof the weapons control reference plane (WCRP). Thestar check method will be discussed further in the nextsection of this chapter.

Establishment of Bench Mark and TramReadings

The sixth major alignment step is the establishmentof bench marks and tram reference readings to furnishan easy means of verifying the alignment of equipmentin the future. It is necessary to have reference readingsbecause the equipment position data dials and datatransmission synchros may become misaligned due towear, vibration, or normal maintenance. Thesereference readings are normally established by ashipyard or NAVSEA representatives after all of thesystem elements are aligned. The application of thesereference readings will be discussed further in the nextsection of this chapter.

Performance of Dynamic Train Alignment

The last major step is the train alignment betweenthe reference and alignable combat system equipmentnot equipped with a telescope. This is accomplished bycomparing equipment position with the position of thealignment reference while simultaneously tracking anisolated target. Fleet and fleet support personnelconduct this alignment.

These steps are used to establish the combat systemalignment. Shipboard personnel are not usually directlyinvolved in most of this process. What we havedescribed thus far is what takes place while a ship isbeing constructed or in a major overhaul.

established, it is the responsibility of shipboardpersonnel to verify and maintain the alignment of thesystem. This is the part of the combat system alignmentthat is more familiar to most fleet personnel.

ALIGNMENT VERIFICATION

Several procedures are fundamental to alignmentverification. In this section we will describe a typicalgun mount alignment verification procedure, includingtram and bench mark readings and star checks. Sinceeach system is configured differently, we will notattempt to explain in any detail how corrections areactually made.

Tram and Bench Mark Readings

Once established, tram and bench mark readingsgive the maintenance person a ready reference to checkthe alignment of the equipment. Apiece of equipmentwill be fitted either for tramming or with a fixedtelescope for sighting a bench mark. Typically, gunmounts and missile launchers are trammed, whiledirectors are aligned to bench marks. Some systems,however, may be fitted for both.

TRAM.— A gun mount is fitted with two sets oftram blocks-one set each for train and elevation. Theblocks are welded, one to the rotating element and theother to a stationary element nearby. Elevation tramblocks are attached, one to the underside of the slide andthe other to the trunnion support. Train tram blocks areattached, one to the bottom of the carriage and the otherto the stand. Tram blocks are provided with machinedplates with concave centers that fit the ends of the trambar. The telescoping tram bar is the most common typein use and will be the only type discussed here.

The telescoping tram bar consists of two parts, onesliding inside the other. The parts have a smallmovement with respect to each other and are extendedby an internal spring. Ascribe mark on the inner part isvisible through an opening in the outer part. Engravedon the edges of the opening is a zero mark. When theinner scribe mark and the outer zero mark are aligned,the tram bar is at the correct length. The tram bar isplaced in the tram blocks, and the gun mount is trainedor elevated to compress or expand the bar until the marksare aligned. This serves to place a known distancebetween two fixed points, corresponding to a specifictrain or elevation angle. Once this angle is determined,it becomes the reference for future alignmentverification.

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Figure 11-3 shows a tram bar installed in a set ofgun mount train tram blocks. Tram readings are takenas an average of several readings. The air drive motorsare used to move the gun mount. Several readings aretaken, moving the mount to compress the tram bar intoalignment alike number of readings are taken, movingthe mount to extend the bar into alignment. By movingthe gun mount in both directions, you can detect any lostmotion in the gear train. The readings are then averagedand compared to the reference readings that areinscribed on a plate normally attached to one of thetrunnion supports.

NOTE

Elevation tram readings are almost alwaystaken with the gun mount trained to 90° fromthe bearing of the high point. At any other trainbearing you will get erroneous elevationreadings due to the offsetting inputs of the rollerpath compensator. Refer to your ship’salignment manual for exact instructions foravoiding this situation.

BENCH MARK— The bench mark is used muchthe same as tram readings. The equipment to be alignedtrains and elevates to align the telescope cross hairs withthe bench mark. The bench mark, however, may besome distance from the equipment you are aligning.This increases the probability that the bearing to thebench mark will change in relation to your equipmentdue to hull distortion. No alignment adjustments shouldever be performed based on a single tram or bench markreading.

Figure 11-3.—Tram bar and tram blocks.

Star Checks

Star checks are used to verify parallelism betweenelements of the combat system and the WCRP. Toillustrate this process, we will assume that the gundirector is also the WCRP. We will now align the gunmount to the director. To begin with, you can fit the gunwith a borescope and all the ballistic and parallaxcorrections are set at zero by the GFCS. The borescopeis inserted into the breech of the gun and its cross hairsaligned with the axis of the bore.

In the evening, a celestial body (star) is selected, andthe directories moved to track the star with its optics. Becareful not to choose a satellite. Satellites show up earlyand are usually very bright. This makes them temptingchoices for star checks. However, once you have lockedonto a satellite, you will find that it moves very quicklyacross the sky, making it difficult to track.

The gun is driven simultaneously with the air drivemotors to track the same star through the borescope.Once the star can be seen through the optics of both thegun and the director, each is moved to pass the verticalor horizontal cross hair over the star. When the star iscentered in the cross hair, the person at the telescopegives a “MARK.” When both the director and the gunMARK at the same time, all the movement is stoppedand the dials are read This is done several times fromeach direction from the bottom and the top in elevationand from the left and the right in train. Each crew thenaverages their train and elevation readings individually.The averages are compared and the gun is adjusted tothe director if the error is out of tolerance.

Each time this is accomplished, the results of theverification, as well as any adjustments, are recorded inthe Combat Systems Smooth Log. Refer to AlignTheory, SW225-AO-MMA-010/OP762, and theappropriate volume of the SW225-XX-CSA-010 seriesof publications pertaining to your ship type for furtherinformation on combat systems alignment procedures.

BATTERY ALIGNMENT

LEARNING OBJECTIVES: Discuss thepurpose and procedures for proper batteryalignment.

The purpose of battery alignment is to adjust all theelements of a weapons system and fire control systemso that the weapons can be accurately aimed and the

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ordnance delivered on target. In other words, youshould target the gun barrel to the exact point that thegun radar or sight is centered on.

Several things may cause your systems to be out ofalignment—normal wear and tear, gun-bore erosion,improper maintenance, alterations/modifications to thesystem or ship, and so on. Initially, alignment isaccomplished in the shipyard by the builder, but thecontinued accuracy of the ordnance installation reliesupon constant maintenance.

SHIPYARD ALIGNMENT

The alignment of a weapons system is primarilyconcerned with the directions that the equipment(launchers, guns, directors, etc.) are pointed. Toestablish directions, you must use a definite andcomplete set of geometric references. The necessaryreferences are contained in the geometric structure,called a reference frame. The reference frame consistsof a reference point, a reference direction, and areference plane.

Directions are expressed by giving instructionsfrom a specific point. Any desired point maybe selectedas the starting point, and once this selection has beenmade, it becomes a part of any measurement. Since thismeasurement must refer to the starting point, it is calledthe reference point.

After a reference point has been selected, it isnecessary to have a reference direction from which tomeasure angles. The angles are measured about thereference point, starting from the reference direction. Innaval ordnance, a fore-and-aft line, pointing in thedirection of the ship’s bow, is the most frequently usedreference direction.

Angles expressing direction cannot be describedcompletely unless a means is available for specifyingthe particular planes in which the angles are to bemeasured. This condition is met when a reference planeis selected. The horizontal plane (also called a deckplane) is one of the most commonly used referenceplanes. When the ship is afloat and you are comparingthe horizontal plane to several other planes, two spiritlevels are necessary for each comparison—theinclination of one plane with respect to another.

The three references described in the precedingparagraphs must all be used when measurements aregiven to describe directions. In the complete referenceframe, directions are specified by two angles measuredabout the reference point. One angle is in the reference

direction, and the other angle is a plane perpendicular tothe reference plane and is measured from the referenceplane.

Before any alignment can be accomplished on anew ship, you must establish the reference frame.During the construction of a ship, one baseplate isinstalled within the ship’s hull. This plate is referencedto a similar plate on a fixed ground installation. Theplate is leveled as accurately as possible before the shipis launched, and an imaginary base plane is figured fromthe average readings taken from the baseplate. Thefoundation and the roller paths for the fire controldirectors, launchers, and gun mounts are machined sothat they are (as nearly as possible) paralleI with the baseplane. The fire control reference plane or weaponscontrol reference plane (WCRP) is the horizontal planeto which all combat system elements are aligned. TheWCRP is perpendicular to the ship’s center line (SCP)and parallel to the ship base plane (SBP). In practice, itis defined by the roller path plane of one and sometimestwo of the major elements of the ship’s combat systemsinstallations.

After battery alignment in train has beenaccomplisheed, you can begin alignment in elevation.The purpose of this alignment phase is to set all theelements so that when they are positioned in elevationwith their lines of sight parallel to their own roller pathplane, the elevation dials of all the elements will readzero and the elevation synchros will be at electrical zero.

So that guns, directors, and launchers can berealigned to the same position, you can provide benchmarks and tram readings. Once established, tram andbench mark readings give the maintenance person aready reference to check the alignment of theequipment. Apiece of equipment will be fitted eitherfor tramming or with a fixed telescope for sighting abench mark. Typically, gun mounts and missilelaunchers are trammed, while directors are aligned tobench marks. Some systems, however, may be fitted forboth. Upon completion of initial alignment orsubsequent realignment by shipyard or supportactivities, you must submit a shipyard alignment reportto the commanding officer of the ship. Included in thisreport are the alignment data, tolerances, demonstrationresults, and any other pertinent data for all of the combatsystems and subsystems aligned by shipyard personnel.This data is maintained in the Combat Systems SmoothLog.

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SYSTEM ALIGNMENT

Shipyard personnel initially install equipment usingprecision methods in a newly constructed ship. Theytake into account stress caused by operational loadingand adjust for accurate alignment when the ship iswaterborne and contains 90 percent of the total load(builder yard only). When alignment procedures areundertaken thereafter, the ship should contain80 percent of the total load of fuel, water, armament, andstores, distributed normally. The greater part of thework will consist of checks and small adjustmentsunless the equipment has been damaged or moved outof alignment.

System alignment requires orienting and adjustingseveral components to each other so that they functionproperly together as a whole. No alignment workshould ever be undertaken without first making carefultests to make certain that adjustment is necessary. Anincorrect or unnecessary adjustment can cause seriousproblems in the system.

SHIPBOARD ALIGNMENT

The alignment requirements for a weapons systeminclude the internal alignment of each of the componentsand system alignment of the different components orequipment with each other. The internal alignment ofan ordnance component is established by themanufacturer. A high degree of machining and fittingof structural parts assures good internal alignment. Ifany basic alignment is necessary because of faultymanufacture, overhaul at a shipyard usually is required.Each director should be internally aligned with theship’s references. All the parts of the weapons systemare aligned to the reference while the ship is beingoutfitted or in dry dock, and the whole system is tested.When the ship is afloat, you must recheck the operationof the system. If there are serious distortions, the shipis returned to the shipyard for adjustments.

The launchers and gun mounts must be aligned tothe directors in train and elevation.

Before any alignment work is undertaken afloat,you should perform a transmission check. Synchro anddial errors corrected at this point will keep you fromcompounding the errors or from introducing errors intothe ensuing alignment procedures. Initially undetectederrors would be revealed before the alignment wascompleted. At this point, you could be faced with thetask of redoing one or more of the alignment phases.

You should not proceed with synchro alignmentunless the preliminary checks show a misalignment. Ifthe synchro is close to zero, you should make only thefine adjustment.

MOUNT ALIGNMENT

Precise mount alignment requires extreme accuracyin the performance of alignment checks andadjustments. These checks should be made with theship moored to a pier or anchored in calm seas.

Train alignment checks provide an accurate methodof determining the degree of parallelism between thezero train lines of all the components of the system.When the director is trained to any point and the mountdial pointers are matched with zero settings, the directorand mount lines of sight are parallel in train.

Because the ship is afloat, it is impracticable to usemultiple targets to obtain parallelism between the mountand director. However, if the lines of sight of both thedirector and the mount are aligned on a target at infiniterange, they will, for all practical purposes, be parallel.The most accurate method of alignment is to use acelestial body.

When train alignment is performed simultaneouslyfor several components, the train dial readings from allthe stations should be transmitted to a central station(such as CIC) for systematic recording. The recordersat the individual components should cross-check all thereadings to eliminate possible errors in recording thereadings. Rotation of the earth and ship’s motion maycause the line of sight to drift from the target, but thisdrift is not detrimental as long as the line of sight is onthe target when the reading is taken.

The mount is aligned in elevation to the director. Itis elevated in manual control to bring its bore (orlaunching rail) into a position parallel to its roller pathplane (at a point of known inclination) within 3 minutesof arc. All the elevation indicators are adjusted toindicate zero elevation.

FIRING CUTOUTMECHANISMS

LEARNING OBJECTIVES: Discuss theimportance of firing cutout mechanisms.

It is hard to overstate the importance of checkingthe firing cutout mechanisms after making the original

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alignment or after doing any work or repair on the mountthat would disturb the firing cutouts. Every casualtycaused by the ship’s firing into their own superstructurestestifies to the seriousness of any misalignment of thefiring stop mechanisms. In every case, these casualtiescould have been prevented. These casualties haveresulted from negligence on the part of ship’s forcepersonnel-the cams were cut improperly (in somecases misaligned) or the firing cutouts were inoperativethrough a lack of preventative or correctivemaintenance.

As you may remember, firing cutout mechanismsare designed to interrupt electrical firing circuits andfiring mechanism linkages whenever guns andlaunchers are trained or elevated to position where firingthe mount would endanger personnel or cause damageto the ship. They should not be confused with thelimit-stop assemblies that are used to limit themovement of some mounts to a safe firing zone. Firingcutout mechanisms do not interfere with the freemovement of the gun or launcher.

The Naval Sea Systems Command has issueddefinite instructions for personnel responsible forplotting, cutting, installing, and checking firing cutoutcams and mechanisms. These regulations are to becomplied with in all cases. In addition, specialinstructions govern particular installations. Thecomputations for the safety clearances of the mountrelative to the ship’s structures and equipment arecomplicated and extensive. A high degree of precisionand skill is required to make these computations and toprepare and install the cutout cams in the mount. Thecomputations are now done with computers at the NavalSurface Weapon Center (NSWC), who prepares thecutout data for the requesting ship. NSWC alsoprepares the cutout cams and assists in their installationand adjustment.

When anew cam is installed, it is essential that thetwo train reference points be reestablished. These arethe train B-end stopped position and the nonpointingzone cam arrested position. The nonpointing zoneswitches must be set accordingly. NSWC personnelwill assist in performing this task

The firing cutout cams are plotted, scribed, and cutduring the final stages of the initial installation oroverhaul period. This is accomplished after all theinstallation and alterations to the topside,superstructure, masts, and rigging are completed.

Procedures for scribing and matching the firingcutout cams are outlined in the applicable system OPs.

Performance of the cams should be checked beforeeach firing, whenever new cams are installed, and asprescribed by the PMS schedule of your system.

The train and elevation limit stops restrict mountmovement under certain conditions. When activated,the limit-stop system neutralizes the associated powerdrive, thus limiting the movement of the mount. Thelimit-stop cam controls the deceleration rate of thepower drive of the mount. Train and elevation requiredifferent rates of deceleration, so their cams differ incontour. The actuating cams are identical. When themount approaches a nonpointing zone, the actuatingcams start the limit-stop system.

An adjustment screw is secured to the bottom ofeach limit-stop cam. As an aid in alignment, scribe linesare scored into the cams. The cam-stacks, whichindicate position-plus-lead to the automatic-pointing-cutout and automatic-firing-cutout systems,have a vernier that permits simultaneous adjustment ofall of the cams in the stack, and each cam can be adjustedto a vernier in its base.

Firing cutout cams, limit-stop cams and associatedshafts, switches, and components are preset by themanufacturer and checked by the installing activity.These cams do not require routine adjustment. Theyshould be checked periodically and reset only if they arenot within plus or minus 1° of actual mount settings.

RADAR ALIGNMENT

LEARNING OBJECTIVES: Discuss theimportance of radar alignment on a guidedmissile battery.

All the elements of a guided missile battery arealigned in the same manner as a conventional weaponsbattery. There is, however, one additional step you mustaccomplish before the physical alignment of the battery.You must first align the radar reference beam and theboresight telescope of the radar antenna. This can beaccomplished by using a shore tower approximately 100feet high and at least 1,300 feet from the ship. The towermust be equipped with an optical target and a tunableradar transmitter.

On some missile systems, the radar beam is used asthe reference for this alignment. The radar beam istrained and elevated to the tunable radar transmitter andelectrically aligned. The boresight telescope is thenadjusted to the optical target and locked in place. In

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other missile systems the boresight telescope is thereference. The boresight telescope is trained andelevated to the optical target on the tower and then theradar beam is aligned to the tunable transmitter. This isthe most critical alignment, because, in both cases, theboresight telescope, after alignment, becomes the onlyreference line of sight for the director. Benchmark datais provided to check this optical alignment periodically.

The above explanation is for dry dock alignmentperformed by shipyard personnel, perhaps assisted bythe ship’s force personnel. When the ship is afloat, theradar reference beam is again checked by the ship’sforce. While at the pier, the shore towers are used. Atsea, all the guided missile ships will use bow and/or sterntowers installed according to current NAVSEAinstructions. Each tower will contain an opticalboresight target, a capture antenna, and a track andguidance antenna.

FINAL ALIGNMENT ANDTEST

LEARNING OBJECTIVES: Discuss theimportance of testing after a battery alignmentand recording the results in the Combat SystemsSmooth Log.

The success of a weapons system depends to a greatextent upon the mechanical and electrical alignment ofthe system. Minor errors in synchro or dial adjustmentscan result in missing the target by a great distance.

If any error corrections were made to train orelevation receiver-regulator dials, you must establishnew alignment readings. Obtain the detailedinstructions for your system and follow them with care.

Upon completion of the train and elevation checks,the elements of the system are rechecked against theirrespective bench marks and new dial readings arerecorded in the ship’s battery alignment and fire controlsmooth logs.

Although both of the above tests can and should beconducted by the ship’s force, it would be wise to askfor technical assistance from a repair facility if you areunsure of the procedures.

Modern ordnance installations are operated almostexclusively in automatic control, except under certainspecial conditions or in emergencies. Therefore, it isespecially important for an installation to be aligned

accurately for automatic operations. If the alignmentmethods described in this chapter are used so that thedials of each element are aligned accurately with thedials of the reference element, you should end up witha good alignment. It is advisable to check the resultsunder conditions which approximate those under whichthe equipment will be used. The checks should beperformed with the system in automatic control and withthe parallax equipment functioning.

If possible, select several targets with differentbearings and at ranges that will be as close as possibleto the mean battle range for the equipment. Forantiaircraft installations, try to use air targets which areat an elevation angle near 45°. The target shouldproduce a slow bearing so that accurate tracking is notdifficult.

Train and elevate the director to track a target asaccurately as possible, especially in train. When ontarget, the director-trainer will call “MARK” bytelephone to the operators at their stations. The operatorat each station observes the target through the boresighttelescope or the boresight and makes a note of any trainerror present when the director is on the target. Thisshould be done for targets at various bearings, somemoving to the right and some moving to the left. In thischeck,some small error is to be expected because thereis always some lag-and-lost motion in the follow-upservomechanisms. Regardless, the error observedwhen tracking to the left should be essentially equal tothat observed when tracking to the right and should bein the opposite direction. If the errors do not changedirection when the direction of tracking is changed or ifthey are considerably larger for one tracking directionthan the other, a misalignment is indicated This can becorrected by adjusting the train synchros. Before anyadjustment is changed, however, a careful analysisshould be made to be certain that the error is not causedby some other factor. For example, a misalignment ofthe sight telescope could cause an error. This should becorrected by boresighting the telescope, not by adjustingthe synchros. Adjusting the synchros, in this case,would result in firing errors. If, after careful analysis,an adjustment is made to the synchros, a check shouldbe made to see whether or not a correspondingadjustment must be made to the dials or any other partof the system.

As you can see, every component in a weaponssystem is linked either directly or indirectly to the others,as are the operators and maintainers of the equipment.You must think and act in terms of the weapons system

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as a whole. What you do, and how your equipmentoperates, will affect the operation of the system as a unit.

Before undertaking any alignment tasks, you shouldbecome thoroughly familiar with the contents ofSW225-AO-MMA-010/OP762, Align Theory, Theoryof Combat System Alignment Manual. This publicationwill assist you in obtaining a general understanding ofthe total combat system alignment methods. It definescombat system alignment, why it is needed, and what itdoes and does not accomplish. The principles ofalignment and the general reasoning behind theprocedures involved in alignment are explained.Detailed instructions for the alignment of specificsystems are not covered in this TRAMAN.

The SW225/OP 2456 series, Total Combat SystemAlignment Manual, contains specific alignmentprocedures for each class of ship. This publication isintended to be used as a guide when performing combatsystem alignment. It is to be used in conjunction withPMS testing and maintenance. PMS tests are designedto check the proper operation of all the subsystems,either as a single entity (total combat system) or asindividual subsystems. Although most PMS tests arenot developed solely for alignment purposes, review ofthe results of those tests that provide alignmentverification over a period of time will indicate trendstoward out-of-tolerance alignment conditions.

The importance of maintaining an alignmentsmooth log cannot be overemphasized. Uponcompletion of the alignment, data must be documentedto provide information for future alignments and toinform responsible personnel of system and subsystemalignment status. A complete and accurate alignmentdata package is essential for effective combat systemalignment.

Upon completion of the initial, or a subsequent,alignment by a shipyard or support activity, analignment report is submitted to the ship’s commandingofficer. The data in this report becomes the base line

information in the Combat Systems Smooth Log forfuture system alignment verification. The CombatSystems Smooth Log is a perpetual record of allalignment, calibration, and internal ballistic data. Theimportance of maintaining the smooth log cannot beoveremphasized. A general outline of data that shouldbe included in the smooth log is provided in table 11-1.Reproducible forms for use in the Combat SystemsSmooth Log are located in the back o fSW225-AO-MMA-010/OP762.

The Combat Systems Smooth Log, section J,contains weapon system configuration data from theShip Configuration and Logistics Support InformationSystem (SCLSIS) Manual for your ship. The centralSCLSIS data base contains the configurationinformation related to each unit’s installed and plannedequipment hardware. It identifies the proper level oflogistics support required to maintain each piece ofequipment. Through the SCLSIS process,configuration data is passed to the Weapon Systems File(WSF) at SPCC, which is used to determine spare partsrequirements for ships. The on-board availability ofspare parts is critical to keeping your systems up andoperational. Therefore, you should always make surethis section is 100 percent accurate. For moreinformation on SCLSIS and SCLSIS reporting, seeNAVSEA Technical Specification 9090-700A.

SUMMARY

The main role of a GM is to deliver the ordnance ontarget. Your weapon system may be fully operational,but if you cannot hit your target, it’s useless. Theimportance of accurate battery alignment cannot beoveremphasized. Although some alignment proceduresare described in this chapter, it is more important thatyou know where to find alignment procedures andinstructions that are written specifically for the systemsyou will be working with on a daily basis.

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Table 11-1.—Smootb Log Data and General Outline

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