Thickness Gauging for Offshore Support Vessels in Aberdeen

Inspection services for ships at Aberdeen

Each service has its own page with the method, the class requirements and what the report contains.

Quays and harbours where offshore vessels are gauged

Most hull gauging in Aberdeen is done alongside in the city harbour, where the team can work deck structure, cargo tanks and engine-room piping while the vessel is in port. Tank work needs the tanks emptied, cleaned and ventilated, and mud or brine tanks in particular need thorough cleaning before readings mean anything, so the cleaning plan is agreed with the master before the team arrives. Working decks are best gauged when cargo has been discharged and the deck can be cleared in sections, with the readings plotted on the deck plan so worn and gouged areas show up as a pattern rather than a list.

The South Harbour handles larger vessels and decommissioning and wind projects, where vessels may stay longer between campaigns. Further along the coast, Peterhead to the north and Montrose to the south are also used by offshore vessels, and both can be reached by road from Aberdeen. For vessels heading to a yard in Norway, the Netherlands or Poland for their renewal survey, an Aberdeen port call is a practical place to do the pre-docking gauging, because the vessel is already alongside and the crew can prepare tanks between voyages.

• Aberdeen city harbour quays — deck plating, cargo tank and engine-room piping gauging on platform supply vessels between voyages.
• Aberdeen South Harbour, Nigg Bay — longer scopes on larger offshore and construction vessels between campaigns, including crane pedestal and A-frame foundation checks.
• Anchor handler berths — stern roller, towing pin and shark jaw foundation inspection, combining UT with magnetic particle crack detection.
• Peterhead harbour — in-service gauging on supply and standby vessels using the port, reached by road from Aberdeen.
• Montrose harbour — gauging on offshore support and wind service vessels working from the port's quays.
• Quiet-period berths — full tank programmes on idle vessels, when cargo tanks can be emptied, cleaned and opened in sequence.

North Sea regulation, charterer audits and the offshore market

Aberdeen lies within the North Sea SOx Emission Control Area, so the offshore fleet burns 0.10% sulphur fuel, and the piping concerns that matter most on these vessels are usually sea-water cooling, fire main, fuel and the cargo lines between the deck manifolds and the tanks. Port state control in UK waters rests with the Maritime and Coastguard Agency, which after Brexit continued to inspect under the Paris MoU on the basis of UK legislation. Many vessels here fly the UK, Norwegian or open-register flags, and flag-state inspections add another layer of scrutiny for owners.

The market context is the energy transition. Oil and gas production on the UK Continental Shelf continues alongside a growing decommissioning workload and a rising number of offshore wind projects off the Scottish coast. With relatively few new offshore support vessels ordered over the past decade, many owners are keeping older tonnage working, moving vessels between oil and gas and wind charters, and taking them through renewal surveys at ages where wastage becomes significant. Charterers' vessel assurance processes expect owners to know the condition of their steel, and an Aberdeen thickness measurement record is a straightforward way to show it.

Ships trading to Aberdeen are inside a sulphur emission control area, where fuel must not exceed 0.10% sulphur unless an exhaust gas cleaning system (scrubber) is fitted. Scrubber wash-water piping, the overboard discharge and the hull penetration around it are among the fastest-corroding parts of a modern ship, so they belong in the gauging scope at every docking and, on open-loop systems, between dockings.

How a thickness measurement job runs at Aberdeen

A gauging job at Aberdeen runs the same way whatever the ship type. The sequence below is what the superintendent, the attending surveyor and the yard can expect from us.

For ship inspection in Aberdeen, the international airport at Dyce is the natural arrival point, with onward connections from London and from European hubs, and the harbour is a short drive away. Supply bases and quays sit behind ISPS-controlled gates, and the vessel's agent or the base operator arranges passes in advance; offshore operators often require site inductions as well, which are completed before the job starts. The team is mobilised from India on UK visas, so we ask for the vessel's expected port days as early as possible and build in a fallback window, because offshore schedules change at short notice.

• Send the vessel name or IMO number, ship type, class society, the survey due (annual, intermediate, renewal survey number, CAP or owner's condition survey), the port and dates, and the scope you expect.
• We confirm the scope against the class rules for that survey, prepare the thickness measurement plan with frame and section references, and say whether the measurement will be credited to a class survey.
• Mobilisation is planned around visa lead times and the vessel's schedule; the ship's agent arranges port access, and the yard or ship arranges staging, lighting, ventilation and gas-free certificates.
• Gauging with calibrated ultrasonic thickness gauges: through sound coatings only where the gauge's through-coating mode has been verified on a coated reference, otherwise on cleaned bare steel, with every reading tied to its frame, strake and location on the sketch.
• Readings are compared with original thicknesses as work proceeds; substantial and excessive corrosion and any cracks are reported to the attending surveyor and the superintendent the same day.
• The final report is issued on the class thickness-measurement formats with sketches, a summary of locations exceeding the allowable margins, piping tables where piping was in scope, and the gauge calibration and technician certificates.

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