Ultrasonic Thickness Measurement for Supply Vessels, Well Boats and Coastal Ships at Sandnessjøen

Inspection services for ships at Sandnessjøen

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

Quays and slipways where a vessel can be gauged at Sandnessjøen

Most gauging here is done afloat. At Horvnes, supply vessels lie at the public quays next to the base warehouses and bulk plant, and tank cleaning is arranged through the vessel operator before anyone enters a mud or brine tank. That cleaning step sets the timetable: a liquid-mud tank that still holds residue cannot be measured, while one cleaned and ventilated over a weather day can. Deck plating, cargo rails, the stern roller area on anchor handlers and engine-room pipework can be reached while the ship works cargo, provided the quay operation allows people on deck.

For hull work out of the water, Slipen Mekaniske's slipway in the town built ferries, fishing boats, gas tankers and cargo ships until 2003 and has since concentrated on repair, maintenance and conversion. A vessel on the slip gives access to bottom plating, sea chests and the stern, which is the moment for a docking-survey gauging programme. Offshore vessels too large for a slipway go to yards further south on the Norwegian coast or abroad, and readings taken in Sandnessjøen beforehand let the owner settle the steel list before the vessel sails. Aquaculture boats, which seldom leave the region, are often measured in the inner harbour during routine service stops.

• Horvnes industrial harbour and supply base — tank, deck and piping gauging on PSVs and standby vessels between field trips or during weather holds.
• Slipen Mekaniske slipway — bottom, shell, sea chest and stern gauging on vessels hauled out for repair or conversion.
• Inner harbour berths — fish-hold, circulation-piping and hull readings on well boats and aquaculture service vessels.
• Coastal express and ferry quays — short machinery-space and car-deck checks during scheduled stops or overnight lay-bys.
• Fishing harbour berths — hull and fish-hold gauging on coastal fishing vessels landing catches or lying up between seasons.

Offshore operators, Norwegian rules and the Helgeland weather

The Norwegian Maritime Authority inspects foreign ships at Sandnessjøen under the Paris MoU, though most of the vessels here are Norwegian-flagged offshore, ferry and aquaculture tonnage for which that authority, or a classification society acting for it, is the flag administration. Supply vessels on the Norwegian continental shelf work under contracts that add the field operators' own vessel requirements to those of class, and the petroleum activity itself is overseen by Havtil, the Norwegian Ocean Industry Authority. Documented hull and tank condition is part of what an owner puts forward when a vessel is offered for a new charter.

Norway was the first state to ratify the Hong Kong Convention on ship recycling, which entered into force in June 2025, so an Inventory of Hazardous Materials is now expected on ships of 500 gross tonnage and above trading here. That touches the ageing end of the PSV fleet: when an older supply vessel is sold out of the North Sea market, the buyer usually wants recent thickness readings alongside the IHM and the class records. In aquaculture the trend runs the other way, towards larger, newly built well boats, but their seawater systems and fish holds still benefit from early baseline readings, because cleaning chemicals and constant flow wear them faster than an ordinary hull.

Wherever a ship is outside a sulphur emission control area, the global 0.50% sulphur cap applies, and many of the ships calling at Sandnessjøen meet it with an exhaust gas cleaning system rather than compliant fuel. Scrubber wash-water piping, the overboard discharge and the hull penetration around it corrode quickly in service, especially on open-loop systems, and are worth adding to the gauging scope.

How a thickness measurement job runs at Sandnessjøen

A gauging job at Sandnessjøen 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.

Sandnessjøen has a small regional airport at Stokka, just outside the town, with domestic connections from Oslo through the regional network; the airports at Mosjøen and Mo i Rana, and the coastal road, are alternatives when weather closes the runway. The base and the public quays are ISPS-controlled, and the vessel operator or the ship's agent registers the team before arrival. Norway is in the Schengen area, so the technicians travel from India on a Schengen visa issued by Norway, and offshore owners who signal planned stops early give the visa time to come through.

• 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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