Thickness Gauging for Ro-Ro, Ro-Pax and Car Carriers at the Port of Hanko

Inspection services for ships at Hanko

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

Gauging windows at Hanko's harbours

The Western Harbour is where most of the work happens. On ro-ro freighters and ro-pax ships we measure main-deck and tank-top plating in the trailer lanes, the areas around lashing points, internal ramps and the stern ramp, working deck by deck as the ship empties and stopping cleanly when loading resumes. Ballast tanks and voids are entered only after the crew has ventilated them and issued an entry permit, so tank work is planned for the longest window in the rotation. Car carriers at the car-import berths give access to car decks between discharge and loading, with the ship lighting the hoistable decks for the team.

Koverhar suits longer jobs on bulk and general cargo ships, where holds, hatch covers and ballast tanks can be measured over a stay that is not governed by a liner timetable. Hanko has no dry dock for merchant ships; the nearest Finnish docking yards are Turku Repair Yard at Naantali and the shipyard at Rauma, and many ro-ro owners dock at yards around the Baltic. Readings from a Hanko call give that yard and the class surveyor a measured starting point, and help the owner decide which tanks and decks must be opened during the dock period.

• Western Harbour ro-ro berths — trailer-lane decks, lashing areas and ramps on ro-ro freighters during lay days or weekend lay-overs
• Car-import berths — car-deck plating, hoistable-deck supports and ramps on car carriers between discharge and loading
• Ro-pax berths — vehicle decks, voids and ballast tanks gauged in stages on ships that cannot leave their rotation
• Koverhar Harbour — holds, hatch covers and tanks on bulk and break-bulk ships with longer, less timetabled stays
• Anchorage in the Hanko approaches — launch-borne jobs on ships waiting for a berth, weather permitting

Inspection, regulation and trade patterns at Hanko

Finland applies Paris MoU port state control through Traficom, the Finnish Transport and Communications Agency, and in a ro-ro port with frequent calls the same ships are seen again and again, so a structural deficiency recorded once tends to be followed up on later visits. On ro-ro and ro-pax ships, inspectors pay close attention to bow and stern doors, ramps and the watertight and weathertight integrity of the hull, which makes wastage and cracking around those openings a practical concern as well as a class item. Hanko's liner services run between EU ports, so their emissions fall wholly within the EU ETS and FuelEU Maritime, and the operators' fleet decisions, whether to replace older tonnage or keep it with steel renewal, rest on the condition data their superintendents collect.

Car carriers raise questions of their own. Battery-electric cars weigh more than the models many car decks were designed around, and they burn differently, so owners of older car carriers are reviewing deck strength and the state of their hoistable decks with that trade in mind. Ice class still matters at Hanko in hard winters, and under the Finnish-Swedish Ice Class Rules the ice belt must keep its scantlings for the ship to keep its class notation. Ships on year-round Baltic rotations collect ice abrasion across many ports, and Hanko's milder conditions often make it the convenient place to measure what those voyages have taken.

Ships trading to Hanko 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 Hanko

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

Helsinki-Vantaa is the nearest international airport, and the team continues by road west along the coast to the Hanko peninsula. Access to the Western Harbour, the Outer Harbour and Koverhar is arranged by the ship's agent, including ISPS passes and, for ships at anchor, a launch. Our technicians come from India and need a Schengen visa for Finland; because Hanko windows are short, we tie mobilisation to a confirmed lay day or call, keep the agent updated on travel, and build consular processing into the plan.

• 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.

Related