Ultrasonic Thickness Gauging for Vessels at Stord and Leirvik

Inspection services for ships at Stord

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

Yard quays, harbour berths and anchorages around Stord

Most gauging at Stord takes place at the yard quays or in Leirvik harbour. At the yard, work on visiting vessels is fitted into the yard's programme and permit system: heavy-lift ships and barges are measured while load-out preparations go on, with the team kept clear of lifting operations and sea-fastening crews. Floating units at the quay offer time and yard services such as staging, lighting and ventilation, which suits extensive ballast tank and hull gauging that would be hard to organise offshore. In Leirvik harbour, ferries and service vessels can be measured during lay-overs and maintenance stops.

For docking, vessels in the area go to repair yards elsewhere on the west coast, around Haugesund and Bergen, or abroad, depending on size and the owner's contracts, and aquaculture vessels often return to the specialist yards that build and maintain them. Readings taken at Stord frequently become the steel list for that docking. Vessels waiting for a yard slot or a towing window can anchor in the sheltered sounds, and a short launch-borne scope is possible there when the agent arranges transport.

• Aker Solutions yard quays — deck, framing, ballast tank and crane-pedestal measurements on heavy-lift ships and transport barges during load-out preparations.
• Yard quays for floating units — ballast tank, column and hull gauging on production or drilling units in for modification, with yard staging and services.
• Leirvik harbour — tank, piping and hull plating checks on ferries, service vessels and coastal cargo ships during lay-overs.
• Aquaculture vessel quays in Sunnhordland — well-tank and circulation piping gauging on well boats during maintenance stops.
• Sheltered anchorages in the sounds — short scopes by launch on vessels waiting for a yard slot or a towing window.
• West-coast docking yards — completion of docking and renewal survey gauging after pre-docking readings at Stord.

Rules for barges, offshore units and coastal vessels at Stord

Foreign-flagged heavy-lift ships, tugs and cargo ships at Stord fall under Paris MoU port state control, carried out by the Norwegian Maritime Authority. Floating offshore units bound for the Norwegian shelf answer to more than class and flag: the Norwegian Ocean Industry Authority, known as Havtil, supervises safety on the shelf, the operator applies its own technical requirements, and a unit in for modification at Stord may need its structural records brought up to date before it returns to the field. Hull gauging on these units follows the class rules for offshore units rather than the ship survey cycle, so the scope is agreed with the class surveyor and the operator before work begins.

Heavy cargo is the particular concern for barges and heavy-lift ships leaving the yard. A topside or module concentrates its weight on the grillage and on the deck structure beneath, and the marine warranty surveyor approving the voyage looks at the condition of that structure as part of the transport plan. Thickness readings of deck plating, longitudinals and transverse frames under the footprint, with magnetic particle testing at padeyes and sea-fastening welds where requested, give the owner documented evidence. For the aquaculture fleet, the issue is continuous seawater circulation through well-boat tanks and piping, which wears steel steadily between dockings.

Ships trading to Stord 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 Stord

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

Bergen Airport, Flesland, is the main international gateway, followed by road and ferry travel south to Stord; Haugesund Airport on Karmøy, reached by road over the Triangle Link, is the other option. The Aker Solutions yard has its own access control, safety induction and permit system, organised through the vessel's owner, the yard or the agent, and the harbour quays are covered by ISPS. As Norway is a member of the Schengen area, each technician mobilised from India needs a Schengen visa; yard and towing dates are usually fixed early enough to apply 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.

Related