0202_A_SEAL_CHANGE_OUT_FOR_REDUCTION_GEAR_MAIN_THRUST_BEARINGS_ARCTICROH20_REV2.docx

USNS ARCTIC

(T-AOE 8)

SEAL CHANGE OUT FOR REDUCTION GEAR MAIN THRUST BEARING(S)REV1

1. ABSTRACT

1.1. Port and Starboard Main Propulsion Thrust Bearings require inspection, cleaning and seal replacement.

2. REFERENCES/ENCLOSURES:

2.1. References:

2.1.1. NAVSEA S9244-A4-MMA-010, Main Thrust Bearing Maintenance and Operation.

2.1.2. NAVSEA S9241-B3-MMA-010, Main Reduction Gear Assembly, Volume I

2.1.3. NAVSEA S9241-B3-MMA-020, Main Reduction Gear Assembly, Volume II

2.1.4. NAVSEA S9241-B3-MMA-030, Main Reduction Gear Assembly, Volume III

2.1.5. MFG DWG 061 000 084- Pad Equalizing. STBD Thrust Bearing Assy.

2.1.6. MFG DWG. 061 000 087- Pad Equalizing. PORT Thrust Bearing Assy.

2.2. Enclosures: None

3. ITEM LOCATION/DESCRIPTION:

3.1. Location/Quantity:

3.1.1. Location:

3.1.1.a. MMR No. 1; 1-455-0-E 3.1.1.b. MMR No.2; 1-510-0-E

3.1.2. Quantity: Two, One each in MMR No.1 and MMR No. 2

3.2. Item Description/Manufacturer's Data:

3.3. Bill of Materials:

3.3.1. The Contractor shall provide additional material such as miscellaneous pipe fittings, gaskets, weld material, cable hangers, cable tags, etc., which are not included in the List of Materials, in order to install a fully functional system which meets the requirements of this specification.

4. GOVERNMENT FURNISHED EQUIPMENT/MATERIAL/SERVICES:

4.1. Government Furnished Equipment: None

4.2. Government Furnished Material:

4.3. Government Furnished Services: None Additional

5. NOTES:

5.1. The contractor and all subcontractors regardless of tier shall consult the General Technical Requirements (GTR) to determine applicability to this work item. In performance of this work item, the contractor and all subcontractors regardless of tier must comply with the requirements of all applicable GTRs including but not limited to GTRs: 1 through 7.

5.2. The contractor and all subcontractors, regardless of tier are advised to review other work items under this contract, including but not limited to work items 009, 010, and 015, 201 through 204 and Item 905 to determine their effect on the work required under this work item. Many of the definitions relating to performance of this work item are found in Work Item 001.

6. QUALITY ASSURANCE REQUIREMENTS: None Additional

7. STATEMENT OF WORK REQUIRED:

7.1. General:

7.1.1. Contractor is responsible for the temporary removal of all interference associated with this work item.

a. Contractor shall clean up and dispose of any liquids or debris resulting from interference removal and work under this item.

b. Ventilation openings and piping shall be fitted with hard gasketed blanks to prevent contamination and unintentional leakage. (WOODEN OR PLASTIC BLANKS ARE NOT PERMITTED).

c. Prior to disconnecting any electrical components contractor shall complete a hook-up sheet for use during reassembly. Wire runs shall be coiled back with ends tapped or bagged.

7.1.2. A containment barrier around the thrust bearing is mandatory and shall be to the satisfaction of the MSCREP.

a. The containment shall be constructed using plastic sheathing or other material to prevent unauthorized access of personnel and the intrusion of foreign material.

b. Once constructed, the contained area must be cleaned thoroughly of any loose debris.

c. Contractor shall verify integrity of containment daily, containment shall be secured when work is not on going and shall remain in place (Except as required to ship and unship bearing components) until bearing and all openings are closed or removal is approved by MSCREP.

d. Checkpoint: Verify containment prior to opening of Thrust Bearing.

7.1.3. Provide a Custom Panels and Control representative to perform removal, reinstallation, and grooming of Shaft Speed indicating system with MSCREP.

7.1.4. Lock-out and tag-out effected systems with the aid of ships force. Contractor is responsible for ensuring equipment is properly secured prior to start of work.

7.1.5. RCC stator vanes may be a potential interference to rigging the thrust bearing cap out of place. Contractor is to evaluate this potential and remove any RCC stator vane assemblies that are determined to be interference in accordance with reference 2.1.5. Fabricate temporary 1/8” steel blanks to bolt to the stator vane openings in the RCC.

7.1.6. Prior to start and during work under this item match mark, bag, tag or otherwise mark all components to ensure proper reassembly in original position.

7.1.7. All disassembly, reassembly, inspection and testing shall be done under the guidance of an authorized OEM representative for the thrust bearing.

7.2. Structural:

7.2.1. Provide and install padeyes, jacking pads, rigging equipment, tooling, and lift fixtures as necessary to disassemble thrust bearing per references 2.1.1 through 2.1.4 and to accomplish static thrust checks and other work under this item. Rigging shall not be accomplished by slinging around pipes, equipment, handrails, or parts of reduction gears.

7.2.2. ANY REQUIRED WELDING IN THE VICINITY OF REDUCTION GEAR SHAFT BEARINGS SHALL BE PERFORMED UTILIZING A LOCAL GROUND TO PREVENT STRAY ARC DAMAGE TO GEARS AND BEARINGS

7.2.3. Provide platforms and staging to accomplish required work and to support components during cleaning and inspection.

7.3. Mechanical/Fluids:

7.3.1. Drain and dispose of residual oil from piping and bearing housing. Hard gasketed blanks shall be installed on open piping connections to the Thrust Bearing and other systems to maintain system cleanliness.

7.3.2. Under the guidance of an authorized OEM representative accomplish work necessary to obtain initial static thrust reading and bull gear CC and CD dimensions prior to disassembly.

7.3.3. Using two 80 ton jacks to jack the line shaft, set the axial position of the thrust bearing in the middle of its travel.

7.3.4. Install additional hard blocking to hold the shaft’s axial position in the event the jacks leak down.

a. Disassembly of propulsion shafting flanges and removal of thrust disc is not required.

b. Maintain location of thrust disc relative to it original ahead location unless regrinding of the shims is required.

c. Completely disassemble thrust bearing to allow for thorough inspection of shoes and leveling links, internal components and housing.

d. Notify MSCREP and ABS when accomplishing initial inspection after opening.

e. All components, thrust disc, and bearing housing shall be thoroughly cleaned and laid out / presented for inspection.

f. Match mark each shim for its location.

g. Measure and record location and thickness of all shims

h. Checkpoint: Match mark and measure shims.

7.3.5. Depending on the results of the bull gear axial position measurements CC and CD, new spacers may be required. Consult with MSCREP and CGSR for final recommendations on spacer sizes on the new forward and aft spacers.

a. Rough machine new spacers as required.

b. Finish grinds each spacer to the specified size within .002 on size and .001 on flatness and parallelism.

c. Mark new spacers to designate their location fwd or aft in the thrust bearing

d. Checkpoint: Witness spacer size measurements, flatness and parallelism checks.

e. Measure and record by group the thickness of each thrust shoe.

f. Verify condition of breather vent

g. Check mating surfaces for nicks and dents

h. Check threads of nuts, bolts, screws, and castings for signs of wear.(ASSUME 25% OF ALL FASTENERS WILL REQUIRE REPLACEMENT AT THE CONTRACTORS EXPENSE)

i. Check babbited surfaces for contamination, nicks, smears, and deformity.

7.3.6. Checkpoint: Thrust bearing components shall be inspected in the presence of the MSFSCREP, CHIEF Engineer and ABS Rep.

7.3.7. Submit as-found condition report documenting condition and recommended repairs to MSFSCREP.

7.3.8. Contractor shall restore all removed components using hand means including Twenty (20) Thrust Pads (Four (4) have embedded RTD’s) per bearing. Contractor shall grind existing shims if directed by MSCREP.

7.3.9. Manufacturing or replacement of parts and/or rebabbiting of pads shall be subject to Change Order.

7.3.10. Prior to reassembly contractor shall conduct blue contact check of thrust bearing halves. Scrape and stone mating surfaces to obtain ninety percent overall contact with a continuous contact band inside the bolt holes at least 1/4 “ wide. It is expected that the bluing and scraping process will have to be repeated several times.

7.3.11. Reassemble thrust bearing under supervision of authorized OEM Representative.

a. Re-assemble thrust bearings using GFM listed in Para 4.2.

b. Install dowel pins and torque to prescribed value in sequence per guidance of authorized OEM Rep.

c. Recheck torque after oil system has been in operation at normal temperatures.

7.3.12. Checkpoint: Inspect thrust bearing components during installation.

7.3.13. Checkpoint: Inspect thrust bearing sealing surfaces immediately prior to installation

7.3.14. Checkpoint: Verify proper RTD operation prior to cover installation.

7.3.15. Checkpoint: After bearing reassembly and prior to operation remeasure thrust float and bull gear CC/CD dimensions. Verify that thrust reading and CC/CD dimensions are within required tolerance.

7.3.16. Checkpoint: Verify proper RTD operation after cover is initially installed and then after tightening.

7.3.17. Reinstall interferences using new gaskets and hardware, install new flame safety shield on all flammable liquid lines following successful completion of dock trials.

7.3.18. Reinstall any removed RCC stator vane assemblies with new o-rings and gaskets in accordance with reference 2.1.5.

7.3.19. Submit condition report documenting final condition and measurements following bearing closing to MSCREP

7.4. Electrical:

7.4.1. Temporarily remove and disconnect Bearing RTD Cabling, and shaft speed indicating system, record hookup data on all wiring. Record wire routing information prior to disconnecting any wiring internal to thrust bearing. Internal leads to pads are soldered.

7.4.2. Reconnect realign and groom bearing RTD and shaft speed indicating system following completion of work on thrust bearing; Final shaft speed system alignment will be accomplished by Government supplied Representative .

7.5. Electronics: None

7.6. Preparation of Drawings/Documentation: None

7.7. Inspection/Test:

7.7.1. CHECKPOINT: For any piping that was cut for interference removal perform 150% hydrostatic test of reinstalled piping. Allowable leakage is None:(CONTRACTOR TO CORRECT ANY LEAKS NOTED PRIOR TO SEA TRIAL)

7.7.2. Verify joint tightness at all disturbed mechanical joints. Allowable leakage is None. (CONTRACTOR TO CORRECT ANY LEAKS NOTED PRIOR TO SEA TRIAL)

7.7.3. Thrust bearing shall be inspected and readings taken every 15 minutes for flow, leakage, pressure and temperature readings during Dock Trials and Sea Trial. This shall be addressed in Sea Trial agenda submitted by contractor. No unusual noise or vibration allowed. All operating parameters shall be within authorized OEM parameters.

NOTE: Normal Max RTD temperature on USNS ARCTIC is less than 170 degrees F during full power. Operating temperatures above this shall be addressed by OEM representative to the satisfaction of the MSFSCREP, ABS and CHIEF ENGINEER. Under no circumstances shall RTD temperature exceed 225 Degrees.

7.7.4. Contractor shall instrument shaft, and record thrust readings between 50% ahead and 50% astern and between 100% ahead an 100% astern. These checks shall be integrated into sea trial test plan submission required in Work Item 204. Submit report of final thrust clearances to MSFSCREP.

7.8. Painting:

7.8.1. All new and disturbed surfaces

7.9. Marking: None

7.10. Manufacturer’s Representative:

7.10.1. Shipyard shall provide authorized OEM representative for thrust bearing listed in 3.0. OEM representative to be onsite and oversee all aspects of work under this item including but not limited to, thrust checks, disassembly, inspection, reassembly, and operational checks during Dock Trials and Sea Trials (Item 022)

8. GENERAL REQUIREMENTS: None Additional.

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