0121_B_LOWER_FOREPEAK_INSPECTION_AND_REPAIRS_Rev1.docx

USNS TRENTON (T-EPF 5)

LOWER FOREPEAK INSPECTIONS AND REPAIRS

1.0 ABSTRACT

1.1 This item describes inspection and repair of hull shell plating of the lower forepeak voids.

2.0 REFERENCES

2.1 8442785 B Molded Lines and Offsets

2.2 8442878 B Standard Structural Details

2.3 8442879 B Weld Schedule

2.4 8442880 B Weld Details Construction

2.5 8442884 A Shell Expansion

2.6 8442887 F Structural Fr 7 Forepeak

2.7 8443364 F General Arrangement

3.0 ITEM LOCATION/DESCRIPTION

3.1 Location: Port and Starboard Lower Forepeak Voids. Frame 7 forward, 2nd platform and below.

3.1.1 400 each slot welds: port and starboard underwater hull, frame 7 and forward. Estimate each slot weld perimeter is 3 inch x 1.5 inch.

4.0 GOVERNMENT FURNISHED EQUIPMENT/MATERIAL/SERVICE: None.

5.0 NOTES

5.1 The contractor and all subcontractors, regardless of tier must 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.

5.2 The contractor and all subcontractors, regardless of tier are advised to review other work items under this contract 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 0001.

6.0 QUALITY ASSURANCE REQUIREMENTS

6.1 The contractor shall document the findings as stated in this SOW and provide a report.

7.0 STATEMENT OF WORK REQUIRED

7.1 Furnish services of Marine Chemist to certify spaces for “Safe for Man” and “Safe for Hot work”.

7.1.1 Note: Port and Starboard lower forepeak voids are not common with each other or to the centerline upper forepeak void.

7.2 Blank void vents and bilge suction piping using contractor provided gasketed steel blanks or pipe plugs. Vents shall be blanked at first flange located within the upper forepeak.

7.3 Pressurize voids to 2 psi using a u-tube manometer in order to prevent over pressurization. Inspection shall occur while the ship is in drydock. Provide access to the void boundaries to include hull shell surfaces, upper forepeak shared plating and frame 7 bulkheads for visual and soap and blow inspection while the voids are pressed up. Inspection shall be in the presence of MSCREP and ABS.

7.4 Remove coating and perform repairs to ten (10) slot welds using reference 2.4 thru 2.6 as guidance.

7.4.1 Prepare an ABS accepted slot weld repair procedure and submit to MSCREP. Demonstrate weld procedure with MSCREP present on sample work piece before welding to hull.

7.4.2 Perform dye penetrant testing of all repaired locations. Testing shall not be accomplished within 3 days after the completion of welding and hotwork. Testing shall be witnessed by MSCREP and ABS. Submit the results of inspection to MSCREP in CFR.

7.4.3 Repeat pressure test of para 7.5 after NDT para 7.6.2. Testing shall be witnessed by MSCREP and ABS.

7.4.4 Investigation may be required for determining sources of leaks in and around locations surrounding the inaccessible void. Additional structural repairs and air leak troubleshooting shall be covered by Contract Change Order.

7.5 Record the results of all work. Provide an electronic copy of the Service Report listing all completed repairs to MSCREP.

7.6 Install contractor furnished coatings and restore disturbed areas to match existing.

8.0 GENERAL REQUIREMENTS: None additional.

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