Ship Gauging and Thickness Measurement at Trelleborg

Inspection services for ships at Trelleborg

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

Where gauging is done at Trelleborg

There is no drydock for large ships at Trelleborg. Ferries are sent for their renewal surveys and refits to yards in Poland, Germany or elsewhere on the Baltic, often during a winter overhaul period, and the gauging done here helps to plan that visit. An operator who knows where the deck, frames, door surrounds and piping have thinned can send the yard a list of steel and pipe renewals in advance, which shortens the time the ship spends out of service.

At the berths, the available time is the whole difficulty. We therefore work in short, prepared blocks. Crew mark test areas, remove deck coverings where agreed, and open access to engine-room spaces; the team starts as the last vehicles leave and aims to be finished as boarding starts. Longer scopes are planned for lay-by periods, relief ships and the occasional weekend when a vessel is held. Cargo operations, security rules and the ship's safety management system control entry to each area.

• Ferry berths — vehicle-deck plating, drainage gutters, ramps and door surrounds on ro-pax ships during turnarounds.
• Ro-ro freight quays — trailer decks, tween decks and lower holds on ro-ro ships between loadings.
• Engine rooms alongside — fire main, sea-water cooling, bilge and ballast piping readings in prepared sections.
• General cargo and forest-product berths — hatch covers and hold structure on multipurpose ships during discharge.
• Lay-by berths — longer programmes on ships relieved from service, held for charter or for sale.
• Yards in Poland, Germany and Denmark — the usual dockings, planned from readings taken here.

Swedish port state control and the ro-pax inspection regime

Port state control in Sweden is carried out for the Paris MoU by the Swedish Transport Agency (Transportstyrelsen). Passenger ships on regular routes between EU ports are covered by Directive (EU) 2017/2110, so ro-pax ferries calling at Trelleborg are inspected by the host state both before they start a service and at regular intervals afterwards. Inspectors give close attention to fire protection, watertight integrity, fire mains, sea-water systems and the structure and securing of bow and stern doors, so recent wall-thickness readings on those items are useful evidence of maintenance.

The regional picture also includes the Swedish and Finnish ice-class rules, which apply to ships that continue north into the Bothnian Sea, and rising emissions obligations. EU ETS has covered shipping since 2024 and FuelEU Maritime since 2025, which puts a financial weight on every crossing; a ferry operator watches hull condition because added roughness and extra weight cost fuel. Every ship entering an EU port must have an Inventory of Hazardous Materials on board under the Ship Recycling Regulation, and surveyors examine the records during port state control.

Ships trading to Trelleborg 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 Trelleborg

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

The usual arrival points are Copenhagen Airport, with its road and rail links across the Øresund Bridge, and Malmö Airport, which is smaller. Trelleborg is roughly an hour from Malmö by road or train. Sweden is a Schengen state, so technicians from India travel on Schengen visas, which should be requested early. Access to the ferry quays is controlled, and the ship's agent or the operator arranges security passes before the team arrives.

• 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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