Thickness Measurement for Crude and Product Tankers at Lysekil and Brofjorden

Inspection services for ships at Lysekil

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

Where a tanker can be gauged around Brofjorden

There is no drydock or tanker repair yard at Brofjorden or in Lysekil, so work here is done afloat, either alongside one of the refinery's jetties or at anchor. At the jetties the terminal's safety rules come first: equipment must be acceptable for the hazardous zones it enters, enclosed spaces are entered only on the ship's permit with a valid gas-free certificate, and the cargo operation sets the timetable. Cargo tanks stay closed during discharge or loading, so in-port scopes concentrate on segregated ballast tanks, void spaces, cofferdams, the forepeak, deck plating and longitudinals, and pipe supports on deck.

Anchorage work is reached by launch booked through the agent, and the exposed outer anchorage used by the largest crude carriers is only workable in moderate seas. For a full renewal or CAP programme, including cargo tanks, the readings taken here feed the yard where the tanker will dock. The largest crude carriers usually dock at big-ship yards far from Scandinavia, while product tankers trading in northern Europe commonly dock in Baltic, Polish or other European yards, and our team can travel there to complete the work.

• Crude oil jetty near the fjord mouth — deck, void-space and segregated ballast tank gauging on crude carriers during discharge, within terminal and master approval.
• Product jetties on the south shore of Trommekilen — ballast tank, forepeak and deck readings on product tankers while they load refinery cargo.
• Anchorage positions east of Bohus-Malmön and around Lindholmen — launch-borne deck, air-pipe and accessible tank work on tankers waiting for a berth.
• Deep-water anchorage south-west of the approach — waiting area for the largest crude carriers, workable for short condition checks in moderate weather.
• Lysekil's town harbour — smaller craft lying in the Gullmarn gauged alongside when a job is arranged.
• The tanker's docking yard — Brofjorden readings carried forward on the TM plan, or the team mobilised to the yard to finish cargo-tank gauging.

Port state control, vetting and tanker rules at Brofjorden

Port state control in Sweden is carried out by the Swedish Transport Agency under the Paris MoU, and oil and chemical tankers more than twelve years old fall into the Paris MoU's expanded inspection category, so the older crude carriers calling at Brofjorden can expect a thorough look at structure, ballast tanks and safety systems. Commercial scrutiny is often tougher still: oil majors and refiners screen tankers through OCIMF's SIRE 2.0 inspections and their own acceptance criteria, and a vetting observation on ballast tank coating or deck corrosion can keep a ship off charter. Ships calling at EU ports also carry an Inventory of Hazardous Materials under the EU Ship Recycling Regulation, and voyages to and from Brofjorden count towards EU ETS and FuelEU Maritime obligations.

For tankers the Enhanced Survey Programme sets the gauging pattern, with transverse sections across the cargo area and close-up survey that grows at each renewal survey, and many charterers now ask older tankers for a CAP rating as well. The corrosion that matters most on a crude carrier is often in places only reachable gas-free: bottom pitting under crude sludge, wastage under heating coils, and grooving at the bottom of longitudinals in cargo tanks. Ballast tanks, where coating breakdown starts at edges, welds and the upper parts of side tanks, are the in-port opportunity, which is why so many Brofjorden calls are used to measure them ahead of a docking.

Ships trading to Lysekil 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 Lysekil

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

Göteborg Landvetter Airport is the nearest international gateway, and from there the team continues by road up the Bohuslän coast to Lysekil and Brofjorden. The refinery harbour is an ISPS facility with its own safety induction, so the agent registers the technicians' names and passport details with the terminal in advance and books launches for anchorage work. Sweden is a Schengen state, so the team travels from India on Schengen visas, and because tanker berthing dates move with the refinery's crude programme, we plan the visa period with room for the call to slip.

• 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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