Ultrasonic Thickness Measurement for Fishing and Offshore Vessels in Peterhead

Inspection services for ships at Peterhead

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

Where vessels are gauged at Peterhead

Fishing vessels are gauged alongside in the inner harbour, usually once the catch has been landed and the holds or tanks washed out. On a pelagic trawler the refrigerated seawater tanks are the main concern: chilled seawater, fish residues and coating breakdown combine to attack tank plating and internal structure, so the tanks are emptied, cleaned and ventilated and the readings are taken in a pattern that shows pitting and grooving as well as general wastage. Shell plating in way of the waterline, fish pump and deck machinery foundations, and seawater cooling and refrigeration piping complete a typical scope.

Offshore and cargo vessels use the deep-water berths in Peterhead Bay, where gauging is done alongside or, for vessels at anchor inside the breakwaters, by boat from the harbour. For a full docking, vessels usually leave Peterhead: larger pelagic trawlers often go to yards in Norway, Denmark or the Netherlands, smaller fishing boats are slipped at yards along the Buchan and Moray Firth coast, and offshore vessels dock at Rosyth or across the North Sea. Readings taken in Peterhead before a refit give the yard a steel and coating list in advance.

• Inner fishing harbour quays — RSW tank, fish hold and shell gauging on trawlers after landing or during refit.
• Peterhead Bay deep-water berths — deck, tank and piping gauging on supply, standby and construction vessels.
• Anchorage inside the breakwaters — short scopes by boat on vessels sheltering from weather.
• Offshore base quays in the bay — deck plating and crane foundation checks between offshore campaigns.
• Cargo berths — hold and tank gauging on coasters discharging bulk and general cargo.

Fishing vessel rules, port state control and offshore audits

Fishing vessels sit outside SOLAS and the normal port state control regime, so their structure is checked mainly through the UK's fishing vessel survey rules, administered by the Maritime and Coastguard Agency for UK-registered boats, through class surveys for those vessels that are classed, and through the owner's own maintenance. Pelagic trawlers fish in harsh winter seas and carry their catch in tanks that are constantly flooded and pumped out, and owners, insurers and buyers of second-hand vessels increasingly expect documented hull and tank condition rather than a visual judgement alone.

Merchant and offshore vessels calling at Peterhead are inspected by the MCA under the Paris MoU, on the basis of UK law since Brexit. Offshore vessels also face charterer assurance and OVID inspections, and the decommissioning and support work handled in the bay brings vessels whose decks and foundations have carried heavy, concentrated loads. On recycling, the UK applies its own ship recycling regulations instead of the EU regulation, which is mainly relevant to owners of older offshore and cargo vessels, and ships trading to EU ports keep an Inventory of Hazardous Materials for those calls.

Ships trading to Peterhead 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 Peterhead

A gauging job at Peterhead 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.

Aberdeen International Airport at Dyce is the arrival point, and from there the team drives north to Peterhead, which has no railway. Travel from India requires UK visitor visas, so we ask fishing vessel owners to tell us about a planned tie-up or refit early, and offshore owners to share likely port days with a fallback date. Access to the fishing harbour and to the bay berths is arranged through the port authority and the vessel's agent or owner, and offshore bases may ask for inductions before work starts.

• 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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