Ultrasonic Thickness Measurement for Ships in Turku and Naantali

Inspection services for ships at Turku

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

Gauging locations around Turku and Naantali

At the Turku ferry berths, gauging is planned with the ship's officers around the timetable. Work inside ballast tanks and voids needs those spaces ventilated and certified safe by the crew before the team arrives, so the tank sequence is agreed in advance and each visit is used for spaces that are ready. Vehicle decks can be measured only when they are clear of cargo, which on a busy route means the night hours or a service break.

Naantali offers more time. Bulk carriers and tankers at its berths can have deck, piping and accessible-space gauging done during cargo operations under the ship's permit system, while a ship in dock at Turku Repair Yard can have bottom plating, side shell and tanks measured as soon as staging and cleaning allow. For an owner choosing where to dock, pre-docking gauging at a Turku or Naantali call gives every yard the same measured steel list to work from, which turns renewal into a planned quantity rather than a figure that grows once the ship is out of the water. Naantali hull gauging in dock is also the point at which ice-belt and damage readings from earlier calls are checked from the outside.

• Port of Turku ferry berths — Åland and Stockholm ro-pax, gauged during turnarounds or lay-by periods with tanks prepared by the crew
• Turku harbour cargo quays — ro-ro and general cargo ships; deck, hold and hatch-cover gauging while cargo is being worked
• Port of Naantali — ro-pax to Kapellskär plus liquid and dry bulk berths; deck, piping and accessible-space gauging during port stays
• Turku Repair Yard, Naantali — docking and repair yard; shell, double-bottom and tank readings taken in dock to settle renewal with the surveyor
• Anchorages in the Turku approaches — ships waiting for a berth or a dock slot, reached by launch arranged through the ship's agent

Regulation and market context for Turku shipping

Finland is one of the Paris MoU's port state control members, and the sulphur limit for fuel used in Finnish waters is the Baltic ECA figure of 0.10%. The Turku ferry routes show the main answers to that limit side by side: LNG propulsion on newer ships, compliant low-sulphur fuel on others, and exhaust gas scrubbers on parts of the wider Baltic ro-ro fleet. Ships fitted with scrubbers need their wash-water and overboard piping watched closely, because acidic wash-water attacks pipe walls and the shell connection. The Baltic is also a NOx Emission Control Area for ships built from 2021 onwards. Voyages between Turku and Stockholm run between EU ports, so all of their emissions count under the EU ETS, which took in shipping in 2024, and under FuelEU Maritime, in force since 2025, even though Åland stands outside the EU VAT area.

Ice is the other constant. The Archipelago Sea freezes in normal winters, and ships calling at Turku and Naantali in the ice season must meet the Finnish winter traffic restrictions, which set minimum ice classes under the Finnish-Swedish Ice Class Rules. Ice-class hulls lose coating and steel along the waterline each winter, and owners who want to keep trading here year-round need ice-belt structure that still meets class requirements. Hull gauging in Finland's archipelago waters therefore often pairs ice-belt work with damage assessment after a contact or grounding.

Ships trading to Turku 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 Turku

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

Most journeys end at Helsinki-Vantaa Airport, followed by a road or rail transfer to Turku; Turku Airport has fewer international links but suits some itineraries. For terminal berths in Turku and Naantali the ship's agent obtains ISPS gate passes, along with launch transport for ships at anchor; for dockings, entry comes through the repair yard. Our technicians need a Schengen visa for Finland, so we agree dates as soon as the docking slot or lay-by is known and keep a margin for consular processing.

• 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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