COMBAT SYSTEM ALIGNMENT

184a. Scope

This section consists of the requirements for performing the mechanical and electric adjustments and alignments of the ship's combat system elements, such as gun mounts, launchers, gun directors, missile directors, 2D and 3D RADAR sets, gyrocompass, stable element and inertial navigation sets.

184b. Definitions

Ship Base Plane (SBP) - The SBP is the basic plane of origin. The SBP is perpendicular to the ship centerline plane and includes the baseline of the ship but is not necessarily parallel to the keel of the ship.

Master Reference Plane (MRP) - The MRP is a plane within the ship parallel to the SBP.

Ship Centerline Plane (SCP) - The SCP is the vertical plane that bisects the ship from stem to stern along its axis of symmetry. It contains the ship's centerline reference line.

Weapon Control Reference Plane (WCRP) - The WCRP is the horizontal reference plane for elements of the combat system. The WCRP is perpendicular to the SCP, parallel to the SBP and is established by reference to the roller path plane one of the major elements of the combat system.

Train zero - Train zero is the train angle at which an element's line of sight, bore axis or pointing line is parallel to the ship's centerline reference sight, bore axis or pointing line is parallel to the ship's centerline reference line.

Elevation zero - Elevation zero is the elevation angle at which an element's line of sight, bore axis or pointing line is parallel to the element's own roller path plane.

184c. General Requirements

To minimize the effects of stresses and distortions resulting from exposure of the ship to direct sunlight, the following alignment operations shall be conducted during the period beginning 3 hours following sunset and ending one hour after sunrise. This period may be extended continuously into additional day-light hours when, in the judgement of the Supervisor, a heavy overcast sky or rain will inhibit ship exposure to direct sunlight. These operations are:

Foundation machining.

Checking the inclination of foundation planes.

Checking the inclination of element roller path planes.

Establishing element train and elevation zero.

184d. Alignment References

The SBP shall be used to establish the MRP.

The MRP shall be used as the foundation machining reference and for verification of foundation machining tolerances.

Ship centerline reference lines shall be established by installation of permanent bench marks in conformance with Sect. 602. These lines shall be used to establish element train zero.

The WCRP shall be used as reference for measurement of the roller path plane inclination of applicable combat system elements.

184e. Detailed Requirements

Foundations for combat system elements shall be machined so that the faying surfaces are flat, smooth and parallel to the appropriate reference plane within tolerances specified. Foundation and element faying surfaces shall meet the condition of contact requirements specified in Sect. 702. Foundations shall be machined only after all structural welding and straightening is complete in the vicinity of the foundation location. Unless otherwise approved by NAVSEA the ship shall be waterborne during foundation machining operations, except for special circumstances when NAVSEA permits machining to be conducted while the ship is on building blocks or equivalent. The foundation machining tolerances for those elements that can be leveled using leveling rings, tapered liners, shims or other device for adjusting element roller path plane shall be plus or minus 20 minutes of arc or one-third the range of the leveling device whichever angle is smaller. Mechanical roller path tilt correctors and digital computer compensation or the equivalent of either are not considered to leveling devices.

1 Section 184

The inclination of the roller path planes of all combat system elements shall be checked and, when possible, leveled to the appropriate reference planes within the tolerances specified. Final verification that element roller path inclination is within specified tolerances shall be conducted when the ship is waterborne and loaded in excess of 90 percent of the weight estimate for sea trials.

Train and elevation zero alignment shall be conducted on all combat system elements and related equipment. All devices in the combat system elements used for transmitting or receiving functional data within each element, between each element of a system and between systems shall be checked for proper alignment. Tram bar readings and bench mark sightings shall be recorded or all elements provided with tram bars and sighting devices.

184f. Alignment Validation

After the combat system has been mechanically and electrically aligned, the Contractor shall conduct validation tests to demonstrate that each sub-system (such as gun system and missile system) and the whole combat system operating as a unit is properly aligned.

184g. Tolerances

The tolerances for each ship class will be specified in its own Tolerances Tables.

184h. Technical Documentation

The primary definitive documentation relating to installation alignment of the Combat System, in the order of precedence, are:

1. The specific ship/ship class Combat System Alignment Manual (SCAM), OP 2456 Series.

2. Theory of Combat Alignment, OP 762.

184i. Testing Requirements

The following tests shall be conducted, in order listed, to verify that the requirements of Sections 184 and 602 have been met:

1. Reference planes and benchmark verification 2. Foundation alignment verification

3. Mechanical battery alignment

Reference planes and benchmark verification - The benchmark shall be verified to be in accordance with the requirements of Sect.

602. After these verifications, the benchmarks shall be used to verify that the reference planes are in accordance with the requirements as specified herein.

Foundation alignment - The Master reference plane shall be utilized for verifying that the foundation machining is in accordance with the requirements as specified herein.

Mechanical battery alignment - Tests shall be performed to verify mechanical alignment including, where applicable, nulling of synchro outputs by external excitation. These synchro alignments shall be performed in accordance with the individual equipment specifications. The mechanical alignment shall include, where applicable, roller path inclination, and elevation and train zero alignments.

The mechanical alignments shall be verified to be in accordance with the requirements as specified herein.

GENERAL SPECIFICATIONS FOR OVERHAUL OF SURFACE SHIPS (GSO)

DEPARTMENT OF THE NAVY NAVAL SEA SYSTEMS COMMAND

SECTION 192

COMPARTMENT TESTING

192a. Scope

This section consists of strength (tightness) and completion test requirements for compartment, tank, and void boundaries.

192b. Definitions

Strength Test - Frequently referred to as tightness test. Strength tests serve to assure the designed strength and tightness of the structure under reasonable expected conditions of use and loading.

Strength tests are performed by applying a pressure equivalent to the specified design head of the structure.

Completion Test - Completion tests demonstrate adequate tightness of a completed compartment, tank, or void. Completion tests are performed by applying air or liquid pressure, by hose testing, or visual inspection. Any lack of tightness is detected by observing the drop in pressure (drop test), the leakage of liquid (leakage test), or visible openings (visual test).

192c. General Requirements

After any alteration or repair work which could affect the tightness of a compartment, tank, or void required to be periodically air tested or inspected, a completion test shall be conducted, except as noted below.

1. Opening of tanks or voids only for inspection or access, or both, does not constitute work requiring a completion test.

2. As an alternate test method to a full compartment, tank, or void completion test, an individual penetration test using one of the methods in paragraph 192f may be substituted, provided:

a. The repaired or altered area is susceptible to localized differential air pressure testing at the required pressure by means of a vacuum box, a pressurized cofferdam, air hose testing, water hose testing, or a running air pressure test.

b. Local record keeping procedures assure that all portions of compartments, tanks, and voids which may have been affected by the work, and could affect watertight integrity are identified and tested.

Completion tests shall not be performed until work on the compartment, tank, or void involved has been completed, including any attachments or penetrations which might affect the tightness of compartment, tank, or void boundaries; however, where practical, completion tests should be performed before painting. All permanent access and closure fittings shall be installed. Should any work, which could affect tightness, be performed on boundaries of a compartment, tank, or void after a completion test has been made, an additional test shall be applied. The additional test need be performed only to prove work done and may be accomplished utilizing alternate test methods of paragraph 192f in order of the following preference:

1. Rerun of completion test as a running air test 2. Cofferdam method

3. Vacuum box method 4. Air hose method 5. Water hose method

6. Chalk test method (preliminary test only)

Only if an alteration involves a change in the design of a tank carrying liquids is a strength test to be performed using either water or oil as the testing medium. In tests requiring 10 lb/in2 and under, where it is considered necessary and safe, an air test may be substituted for the testing medium. The pressure shall be in accordance with existing Compartment Test Schedule requirements or the construction drawing; however, the pressure selected must not exceed the design head for the weakest boundary of the tank. If a strength test is conducted, the completion test is not necessary, provided the strength test is conducted after all work affecting the tightness of the structure has been completed.

Design heads are in feet of salt water unless otherwise specified; however, salt water shall not be used as the testing medium. If a design head is specified, an equivalent head of the testing liquid shall be used.

When a compartment, tank, or void is ready for testing, the Supervisor shall be notified and testing shall not proceed until the Supervisor has inspected the space and authorized proceeding with test.

Unless specified otherwise in the Schedule of Watertight Integrity Tests and Inspections (SWITI), and except as noted in paragraph 192d, the air pressure for completion tests shall be 2 lb/in2 for watertight and oiltight structure and 4 oz/in2 for air tight structure.

1 Section 192

A compartment, tank, or void tested by a completion air test will be considered sufficiently tight if the drop in air pressure, from the specified test pressure, during a 10-minute period does not exceed the following values:

Compartment Allowable Drop

For those cases where the pressure used is less than 2 lb/in2 allowable pressure drops shall be changed in the ratio of actual pressure to 2 lb/in2.

If performing an air pressure test, the space being tested shall be pressurized and maintained at test pressure for 15 minutes for temperature stabilization before beginning the 10-minute test.

192d. Miscellaneous Tests

New or repaired bilge keels, rudders, rudder support assemblies, and shaft tubes shall be tested to a pressure of 5 lb/in2. Under these tests, there shall be no drop in pressure over a 10-minute period.

These tests shall be conducted prior to filling with preservative coating. Sonar domes shall be tested as required by the individual Sonar Dome Handbook if a dome is repaired or replaced.

New compartments, tanks, or voids installed on a ship shall be tested in accordance with the completion or strength test requirements on the construction drawing. Completion test requirements shall be added to the SWITI.

192e. Air Test Fittings

An air test fitting (drawing, NAVSHIPS No. 810-1385791) shall be provided for each new compartment which requires periodic air testing. Air test fittings, where practicable, shall be located on or adjacent to the normal access of the compartment. Air test fittings on hatches shall be located so as not to form an obstruction to traffic. Air test fittings shall be used for the purpose of conducting completion air tests.

192f. Alternate Test Methods

Running Air Test Method - Running air tests, used in lieu of completion tests, shall be performed as follows:

1. Pressurize the space to the specified completion test pressure.

2. Boundaries of the space, which have been affected by repair or rework, shall be inspected for leakage by applying a soapy solution to the outside of the structure under pressure or by using an ultrasonic translator detector (similar to Hewlett Packard Delcon 4905A).

3. Acceptance criteria for running air tests shall be no evidence of leakage indicated either by no formation of bubbles in the soapy solution or no reading on the ultrasonic translator detector.

Cofferdam Test Method - A pressure cofferdam can be used to verify tightness of patches or components after reinstallation, if it is physically possible to cover the item. Cofferdam tests, used in lieu of completion tests, shall be performed as follows:

1. Install the cofferdam over joint or fitting to be tested so that the pressure differential will be in the same direction as a full compartment, tank, or void completion test.

2. Pressurize the air space inside the cofferdam to the test pressure specified for the completion test of the applicable compartment, tank, or void.

3. Apply a soapy solution to the opposite side of the structure and inspect for leakage.

Acceptance criteria for cofferdam tests shall be no evidence of leakage indicated by no formation of bubbles in the soapy solution.

4. If the opposite side of the structure is inaccessible, an alternate method of proving tightness is to measure the drop in pressure within the cofferdam over a 10-minute period. The gasket and fittings in the cofferdam should be checked for leakage using a soapy solution. Acceptance criteria for this alternate cofferdam test shall be no drop in pressure.

Vacuum Box Test Method - A vacuum box can be used to verify the tightness of patches or components after reinstallation, if it is physically possible to cover the item. Vacuum box tests, used in lieu of completion tests, shall be performed as follows:

1. Apply a soapy solution to the joint to be tested.

2. Install the vacuum box over the joint or fitting to be tested so that the pressure differential will be in the same direction as a full compartment, tank, or void completion test.

3. Draw a vacuum to obtain a pressure differential comparable to the completion test pressure.

4. Inspect the joint or fitting for leakage by observing through the plexiglass cover of the vacuum box for the formation of bubbles.

5. Acceptance criteria for vacuum box tests shall be no evidence of leakage indicated by no formation of bubbles in the soapy solution.

6. An alternate test method of proving tightness with the vacuum box is to measure the rise in pressure within the vacuum box over a 10-minute period. The gasket and fittings in the vacuum box shall be checked for leakage using a soapy solution. Acceptance criteria for this alternate vacuum box test shall be no rise in pressure.

Air Hose Test Method - Air hose tests, used in lieu of completion tests, shall be performed as follows:

1. The air hose nozzle shall be about 3/8 inch in diameter and the pressure at the nozzle shall be about 90 lb/in2.

2. Apply a soapy solution to the structure on the side opposite from the side the stream of air is to be applied.

3. The air hose shall be applied to produce a pressure differential in the same direction as would occur if a full compartment, tank, or void test were performed. Hold the nozzle as close as possible to the joint or fitting under test and direct the air stream in the manner most likely to reveal leakage.

4. Test procedures using the air hose test method shall contain the following statement, "WARNING: High velocity air is a personnel hazard. Nonessential personnel shall be cleared from the area being tested. Safety glasses shall be worn at all times. Care must be taken so that the air stream is not directed toward any personnel."

5. Acceptance criteria for air hose tests shall be no evidence of leakage indicated by no formation of bubbles in the soapy solution.

Water Hose Test Method - Water hose tests, used in lieu of completion tests shall be performed as follows:

1. The water hose nozzle shall be no less than l/2 inch in diameter and the pressure at the nozzle shall be no less than 50 lb/in2.

2. The nozzle shall be within ten feet of the structure under test and the stream of water shall be directed against all portions of the structure in the manner most likely to develop leaks.

Inspect the opposite side of the structure being tested for signs of water seepage.

3. All test procedures using the water hose test method shall contain the following statement, "WARNING: Prior to water hose test, conduct a survey to assure that appropriate steps and precautions have been taken to prevent damage caused by spillage or spray of fluid on ship's components and equipment adjacent to test area and to contain fluid if leakage should occur."

4. Acceptance criteria for water hose test shall be no evidence of water on the opposite side of the tested structure.

Chalk Test Method (Preliminary Test Only) - A chalk test may be used as a preliminary test for reworked knife edges and gaskets on watertight doors and hatches. One of the preceding test methods must be used to prove work tight. Chalk testing is performed as follows:

1. Chalk the bearing surface of the knife edge and close the door or hatch by normal procedure.

2. When the door or hatch is opened, the chalk from the knife edge will have been transferred to the gasket.

3. Acceptance criteria for the chalk test is a uniform and continuous chalk mark on the door's or hatch's gasket. If there are irregularities or breaks in the chalk mark, the gasket or knife edge must be adjusted or replaced and the test repeated.

192g. Safety Precautions

Safety precautions of Naval Ship's Technical Manual, NAVSEA 0901-LP-884-0004, Chapter 9880, Section IV, shall be followed to prevent over-pressurization of the compartment or tank being tested.

192h. The Schedule of Watertight Integrity and Inspections (SWITI)

The SWITI shall be updated to reflect only revisions to compartment numbering or changes to compartment tightness requirements made during the overhaul for use by ship's force in conducting periodic inspections after the ship completes overhaul. The Contractor is not responsible for conducting periodic tests and inspections unless specifically authorized,

3 Section 192

(THIS PAGE INTENTIONALLY LEFT BLANK))

GENERAL SPECIFICATIONS FOR OVERHAUL

This section contains general requirements for overhaul and repairs to the complete machinery plant. These requirements supplement those specified in the other sections of these specifications covering systems and component parts of the plant.

200b. Definitions

The machinery plant consists of the propulsion plants, independent auxiliary plants, independent auxiliaries and equipment with supporting piping, electrical and control systems required for the ship.

A propulsion plant consists of the propulsion unit steam generators, propulsion auxiliaries, associated equipment, control systems, piping systems, and electrical systems that are required to drive one propeller.

A propulsion unit consists of the machinery and equipment that are mechanically, electrically, or hydraulically connected to a propulsion shaft.

Propulsion auxiliaries are those auxiliaries directly associated with a propulsion plant, which perform functions essential to the operation of the propulsion plant.

Propulsion auxiliaries are those auxiliaries directly associated with a propulsion plant, which perform functions essential to the operation of the propulsion plant.

In document General Specifications for Overhaul of Surface Ships (GSO).pdf (Page 176-182)