SOW.pdf

Hull Plating (Side Scan), Ultrasonic Testing

1. SCOPE

1.1 Intent. This work item describes the requirements for the Contractor to perform thickness measurements of the underwater (u/w) body and freeboard by ultrasonic side scan method.

1.2 Government-furnished property.

None.

2. REFERENCES

COAST GUARD DRAWINGS

Coast Guard Drawing 87 WPB 085-013, Rev B, Docking Plan

Coast Guard Drawing 87 WPB 111-001, Rev H, Shell Expansion

Coast Guard Drawing 87 WPB 111-050, Rev A, Updates to DWG 87-WPB-111-001 Exhaust Port Insert Plate Installation and Details

COAST GUARD PUBLICATIONS

Surface Forces Logistics Center Standard Specification 0000 (SFLC Std Spec 0000), 2022, General Requirements

OTHER REFERENCES

American Society for Nondestructive Testing (ASNT) SNT-TC-1A, 2016, Recommended Practice for Personal Qualification and Certification in Nondestructive Testing

3. REQUIREMENTS

3.1 General.

3.1.1 CIR.

None.

3.1.2 Tech Rep.

Not applicable.

3.1.3 Protective measures. The Contractor must furnish and install all protective measures in accordance with SFLC Std Spec 0000, paragraph 3.3.3 (Vessel component, space, and equipment protection).

3.1.4 Interferences. The Contractor must handle all interferences in accordance with SFLC Std Spec 0000, paragraph 3.3.5 (Interferences). Known interferences include, but are not limited to the following:

Hull zinc anode system

Docking blocks

3.2 Work coordination and preparation. The coast guard will complete specified vessel work detailed in this specification package to ensure the side scan survey does not necessitate a work stoppage. The goverment will abide by the following guidance, to facilitate the ultrasonic survey:

Ensure that all freeboard and u/w body surface preparation and primer coat application tasks are completed prior to the survey.

Prior to side-scan survey, inspect interior and bilge plating for the presence of bubbles of rusted metal. Break up and remove all rust bubbles to ensure accurate survey results.

Provide a continuous supply of fresh water at .50 gpm within 50 feet of the vessel with standard hose bib fitting.

Provide 110 VAC electrical power, and scaffolding or other suitable means of access to bring inspection personnel within one foot of all the hull surface inspection areas that are five feet above ground level.

3.3 Side scan requirements and procedures. The Contractor must ensure the following referring to Coast Guard Drawings 87 WPB 085-13, 87 WPB 111-001, and 87 WPB 111-050 as guidance during the performance of the tasks specified below.

3.3.1 Testing company and personnel. Provide the services of a qualified ultrasonic testing company, with suitable side scan equipment, to conduct a “Scanning Crawler Automated Test” of the vessel’s freeboard and u/w hull plating for the presence of metal corrosion and deterioration. Ensure the following:

All scanning operations are completed by personnel meeting the personnel qualification and certification, as required by contractor process. This contractor-developed personnel qualification and certification process must meet, at a minimum, ASNT Recommended Practice No. SNT-TC-1A.

An ASNT Level III Analyst is on site, to oversee the project and evaluate the collected data.

An ASNT Level III or II Analyst is on site, to verify with a hand held gauge all areas on the hull identified as thinner than the specified criteria, in order to expedite all repair procedures.

Qualified personnel are provided to complete all on-site inspections.

3.3.2 Coast Guard notification.

3.3.2.1 Provide a daily update to the COR on all areas inspected and potential issues or schedule changes.

3.3.2.2 Notify the COR at least 3 days prior to completion for an onsite review of readings and repair areas.

3.3.3 Scanning parameters. Use the following parameters during the course of this inspection:

Automated scanning resolution must be set to 0.5” x 0.5”

Plates where scan data indicating wastage greater than or equal to 25% nominal plate thickness must be highlighted in “RED” and designated “repair areas”.

Plates where scan data indicating wastage greater than or equal to 15% to 24% of nominal plate thickness must be highlighted in “YELLOW”.

Plates where scan data indicating wastage greater than or equal to 10% to 14% of nominal plate thickness must be highlighted in DARK GREEN.

Hand held UT readings must be taken to verify bad metal areas found with the side scan equipment. All readings must be provided to the COR and the lowest reading marked on the hull at the bad metal location.

Areas that are accessible but cannot be reached by the automated scanner must be scanned with a hand-held meter at a resolution of 2” x 2”. Any repair areas found during the hand scan must be marked on the ships hull and their approximate positions recorded on the plate drawings and report summary.

3.3.3.1 Any scanning parameter or scope of work changes must be approved by the KO.

3.3.3.2 The echo to echo transducer is not authorized due to inconsistent readings and technical difficulties.

3.3.3.3 There must be no deviation from the color scheme specified above.

3.3.4 Ensure that the side scan inspection area includes the Port, Starboard, and Transom exterior shell plating, but must exclude the following list.

Areas under and within 6-inches of blocks and side blocks (areas that are accessible 6 inches from blocks and side blocks must be hand scanned.)

Areas up to 6-inches around any obstacle on the hull including sea suctions, discharges, rudderposts, anodes, stern tubes, and docking blocks.

Any areas blocked by immovable scaffolding or shipyard activity.

3.4 Side scan reports. The Contractor must submit a CFR containing the final report within three working days after the side scan inspection is completed. A copy of all repair areas must be clearly marked, in yellow or white, on the provided shell plate drawing(s), and provide a summary document of same areas.

Submit two hard copies of the report with two CD’s containing the electronic (raw) data prior to departing the job site. Ensure the reports include:

Inspection overview.

Data sheets for each plate with designated repair areas outlined in blue.

Mosaic of scanned data overlaid on Coast Guard Drawing 87 WPB 111-001.

NOTE

Where hull repairs are required in the vicinity of the exhaust teardrops, use Coast Guard Drawing 87 WPB 111-050 for guidance on location of stainless steel hull inserts and when planning for plating renewal.

3.4.1 Photos. Provide digital photos of all designated repair areas.

3.4.2 Electronic files. Ensure CD’s contain a complete copy of the report, interactive data files, and digital pictures. All electronic files must be compatible with standard USCG workstation operating software.

Electronic files format must be such that the CG has the capability to change the percent of wastage (format conditioning) per plate. Electronic files must be capable of being opened using MS Word, MS Excel, or PDF software. Digital pictures must be recorded in JPEG format.

3.5 Touch-up preservation. The Contractor must prepare and coat all disturbed interior bilge surfaces to match existing adjacent surfaces in accordance with SFLC Std Spec 6310, paragraph 3.1.13 (Touch-ups and minor coating repairs.)

4. NOTES

This section is not applicable to this work item