Ultrasonic Thickness Measurement for Ferries, Coasters and Workboats at Oskarshamn

Inspection services for ships at Oskarshamn

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

Gauging at the floating dock, the ferry berths and the cargo quays

Damen Oskarshamnsvarvet, the harbour's ship repair yard, works a floating dock and a repair quay for vessels that trade mainly in the Baltic: ferries, general cargo ships, workboats, fishing vessels and pilot and coastguard craft. When a ship is lifted in the floating dock, the bottom and side shell, sea chests, rudder area and double-bottom tanks can all be gauged with the yard's staging and lighting in place, and the readings handed to the yard planners before blasting and steel renewal begin. The yard decides whether a given ship fits its dock; we work for the owner or manager, alongside the yard's programme and the attending surveyor.

Larger bulk carriers and tankers that exceed the dock's limits still have useful windows here. At the cargo quays, holds can be measured as they empty, and ballast tanks prepared by the crew can be entered during a longer stop. The ferry berths suit small in-service scopes on piping, vehicle decks and void spaces during a layover, split across several calls if needed. Ships waiting off the port in calm weather can be boarded by launch for a short deck and air-pipe scope arranged by the agent. For a renewal survey on a ship too big for Oskarshamn, the readings taken here become the pre-docking estimate for whichever yard the owner has chosen.

• Damen Oskarshamnsvarvet floating dock — bottom, side shell, sea chests and tanks gauged on ferries, workboats and coasters while the hull is lifted.
• Yard repair quay — afloat repair periods, with piping, deck and tank readings taken alongside the yard's steelwork and blasting.
• Gotland ferry terminal — machinery piping, vehicle decks and voids measured during layovers between Visby crossings.
• Cargo quays — hold, hatch coaming and ballast-tank readings on timber and bulk ships during loading or discharge.
• Waters off the harbour approach — short deck and air-pipe scopes by launch on ships waiting for a berth, weather permitting.

Port state control, ferry inspections and the Baltic short-sea fleet

Ships calling at Oskarshamn fall under Paris MoU port state control, carried out in Sweden by the Swedish Transport Agency. Ro-pax ships and high-speed craft on regular services face a further layer: the EU regime for inspecting the safe operation of ro-ro passenger ships in regular service, under which the authorities inspect a ship before it enters a service and periodically afterwards. Hull and vehicle-deck condition sits naturally inside that attention, and an operator that can show recent thickness data on car decks, ramps and ballast spaces goes into those inspections with fewer open questions. Non-EU-flagged ships calling here must also carry an Inventory of Hazardous Materials under the EU Ship Recycling Regulation.

Much of the tonnage on this coast is small and old by deep-sea standards. Short-sea coasters in the Baltic timber and bulk trades often keep working for decades, and many carry Finnish-Swedish ice class so that they can serve northern ports in winter. General cargo coasters fall outside the Enhanced Survey Programme, yet their owners face the same questions about wastage in holds, double bottoms and hatch covers, especially before a sale or a long charter. Workboats and fishing vessels add their own pattern of wear, concentrated at the waterline, around fendering and in wet spaces, which is why condition gauging on them tends to follow damage or a planned refit rather than a fixed calendar.

Ships trading to Oskarshamn 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 Oskarshamn

The sequence for a thickness measurement job at Oskarshamn is short and written down, so the yard, the surveyor and the superintendent know who arranges what.

Technicians usually fly into Copenhagen or Stockholm Arlanda and continue by train or road; Kalmar Airport, further south on the same coast, has domestic flights from Stockholm. Sweden is in the Schengen area, so the team travels on Schengen visas, applied for as soon as the yard slot or the call is known. Entry to the shipyard is by yard pass, and access to the ferry and cargo quays goes through the ship's agent, who also books a launch when a ship is to be boarded off the port.

• 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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