Ultrasonic Thickness Gauging at Mukran Port and Sassnitz on Rügen

Inspection services for ships at Sassnitz

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

Where gauging happens at Sassnitz and Mukran

Most work is at Mukran's quays. Service operation vessels lie alongside for crew change and stores, a window of hours rather than days, and the scope is agreed with the vessel's technical team to fit it. Crew transfer vessels are alongside every evening and at weekends when weather keeps them in port, which gives repeated short windows that suit a campaign across a fleet rather than one large job. Heavy-lift ships at the heavy-load terminal lie alongside while cargo is delivered and secured, and their holds and decks can be measured outside the lifting zone. Mukran has no drydock, so dockings go to yards elsewhere on the Baltic or the North Sea, and CTVs are usually lifted out at smaller yards around the coast.

Work on the floating LNG terminal is planned with its operator and follows strict gas-safety rules, with access confined to spaces outside the cargo containment, such as ballast tanks, voids, deck structure in safe zones and engine-room systems. The Bornholm ferry turns around quickly and is gauged mainly for systems the crew can release. In the old harbour, fishing vessels and excursion boats are examined at their home berths in winter. Ships at anchor off Sassnitz can be reached by boat for small scopes, though easterly weather often rules that out.

• Mukran O&M berths — hull, deck and tank gauging on crew transfer vessels, with penetrant testing of welds on aluminium structure.
• Mukran quays for service operation vessels — tank, deck and piping gauging, plus magnetic particle testing of gangway and crane pedestal welds at crew change.
• Heavy-load terminal — tank top, tween-deck and hatch cover gauging on heavy-lift and multipurpose ships while wind components are loaded.
• Floating LNG terminal — ballast tank, void, deck and sea water piping gauging under the operator's permits, outside the cargo containment.
• Ferry berth — piping, void and tank checks on the Bornholm ferry during its port stay.
• Sassnitz old harbour — hull and deck plating on fishing cutters and excursion boats during the winter off-season.

Offshore rules, LNG operations and port state control

Cargo ships, ferries and offshore vessels calling at Mukran come under German port state control within the Paris MoU, carried out by the Ship Safety Division of BG Verkehr. Offshore service vessels are also inspected by their charterers, the wind farm operators, whose vetting looks closely at gangways, cranes and the structure supporting them. EU climate rules are extending to this fleet: offshore ships of 5,000 GT and above have reported emissions under EU MRV since 2025 and are due to enter the EU Emissions Trading System from 2027, while smaller offshore vessels from 400 GT also report under MRV. Ships of every flag calling here need an Inventory of Hazardous Materials.

The LNG terminal brings gas-carrier rules into a port that was built for ferries. Floating storage and regasification units are kept on station for long periods, so their class follows a programme designed to avoid regular dry-docking, and owner's condition gauging helps track ballast tank and piping wastage in between class surveys. LNG carriers delivering cargo work under terminal procedures that restrict any outside work aboard. Mukran's offshore role is growing as new Baltic wind farms are built and older ones need maintenance, which keeps a large fleet of small service vessels working out of the port all year.

Ships trading to Sassnitz 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 Sassnitz

A gauging job at Sassnitz 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.

Berlin Brandenburg and Hamburg are the main international airports, with rail connections through Stralsund to Sassnitz; Rostock-Laage is closer but has few international flights. Mukran's terminals are ISPS-controlled, and the LNG terminal and offshore operators add their own inductions, so the agent or operator registers the team well before arrival. Technicians from India travel on Schengen visas, and offshore vessels' crew-change dates are usually fixed weeks ahead, which helps us book the mobilisation in good time.

• 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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