Thickness Gauging for Crude Tankers Loading at Sture, Norway

Inspection services for ships at Sture

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

Where a tanker can be gauged at Sture

The jetty is the main location. The tanker's agent submits the team's names and equipment list well ahead of the call, the terminal issues passes and safety instruction, and the master and terminal agree a permit to work before boarding. Our instruments and couplants are chosen to suit the hazardous-area rules, and the scope is divided between spaces that can be read while cargo moves and spaces that must wait. Ballast tanks need to be ventilated and gas-free in advance, so the crew starts preparation on passage to the terminal.

There is no repair yard at Sture, and ships that need steel renewal usually dock at yards on the Norwegian coast or elsewhere in northern Europe. Gauging at the jetty gives the steel estimate and a record that class and the yard can use in planning. Tankers sometimes wait in sheltered fjord waters for a berth, and a short launch-borne scope on deck and in accessible tanks may be possible there, though the terminal's rules and the weather decide.

• Terminal jetties: deck plating, external piping and manifold-area structure outside the cargo hazard zone.
• Segregated ballast tanks: wing, double-bottom and peak tanks entered under permit once gas-free.
• Forepeak, aft peak and cofferdams: readings taken while loading continues in the cargo tanks.
• Engine room and sea-water piping: scrubber overboard lines and cooling systems on tankers fitted with scrubbers.
• Fjord anchorage areas: short launch-borne scopes on tankers waiting for the berth, subject to terminal rules.

Norwegian port state control, vetting and the tanker trade

Norway is a Paris MoU member, and port state control is carried out by the Norwegian Maritime Authority. Crude oil tankers are among the ship types that inspectors look at most closely, especially older vessels, where structural condition in ballast spaces and the deck is examined and thickness records may be requested. Norway is also part of the European Economic Area, so many EU maritime rules, including those on hazardous materials inventories for ships, apply through the EEA Agreement.

Tanker vetting is a commercial discipline here. Terminal operators and charterers inspect crude tankers against industry vetting standards, and a vessel with documented wastage close to the allowable diminution and no repair plan will draw questions. An owner trading medium and large crude tankers from the Norwegian terminals therefore benefits from current thickness evidence. Since the terminal is in a sensitive fjord environment, environmental rules add care around any leak or spill risk, which is another reason to keep piping and deck steel in sound condition.

Ships trading to Sture 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 Sture

A gauging job at Sture 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.

Bergen Airport Flesland is the nearest airport, with connections through Oslo and several European hubs, and the team travels by road to the terminal. The terminal controls entry, and passes and safety inductions are arranged through the vessel's agent in advance. Norway is in the Schengen area, so technicians from India travel on Schengen visas applied for once the call is confirmed; owners with regular Norwegian calls can keep visas valid. Any launch for fjord anchorage work is booked by the agent.

• 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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