Ultrasonic Gauging for Bulk Carriers and Steel Cargo Ships at Oxelösund

Inspection services for ships at Oxelösund

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

Gauging at Oxelösund's bulk and steel berths

The discharge berths serving the steelworks are where most of the work happens. As each hold is emptied, the tank top, hopper plating, side frames and brackets become accessible, and the team can gauge them and record grab damage before the hold is swept or the ship moves on. Hopper and topside tanks are entered once the crew has issued a gas-free certificate and an enclosed-space entry permit. The stevedores' programme sets the order, so the scope is planned hold by hold with the chief officer, and quay movements follow the terminal's safety rules.

At the steel loading quays the window is the time before plate is stowed, which suits tank-top and lashing-point readings and crack detection at load-bearing details. Ships waiting for a berth sometimes lie at anchor off the port; short deck and air-pipe scopes can then be done by launch, arranged through the agent, if the weather allows. Oxelösund has no drydock for ships of this size, so a renewal survey programme is finished at the docking yard the owner selects, and the readings taken here travel with the ship as the pre-docking steel estimate.

• Ore and coal discharge berths — hold, hopper and topside tank gauging as each hold empties, with grab damage recorded by frame.
• Steel loading quays — tank-top, lashing-point and hatch-coaming readings on multipurpose ships before plate is stowed.
• General dry bulk berths — cargo hold and ballast tank measurements on bulk carriers serving the port's other customers.
• Anchorage off the approach — short deck and air-pipe scopes by launch on ships waiting for a berth.
• Docking yards elsewhere in the Baltic or North Sea — the rest of a renewal programme, built on readings taken here.

Bulk carrier rules and a steel industry in transition

Port state control at Oxelösund follows the Paris MoU and is carried out by the Swedish Transport Agency, and older bulk carriers rank among the ship types that the Paris MoU targeting system looks at most closely. Bulk carriers also carry their own body of structural rules. The Enhanced Survey Programme sets the gauging and close-up survey extent at each renewal, SOLAS chapter XII adds structural requirements for bulk carriers, and on single side skin ships IACS UR S31 sets renewal criteria for side shell frames and brackets in the cargo holds. Those frames, wasted at their lower ends and damaged by grabs, are a classic finding on ships in ore and coal trades.

The steel industry around Oxelösund is part of Sweden's push towards fossil-free steel, and the shift to electric arc steelmaking changes the cargo the port receives. Scrap and heavier, more abrasive cargoes treat holds differently from ore pellets and coal, so owners moving ships into that trade, or taking them on charter for it, have good reason to record the condition of tank tops, hopper plating and frames before the first cargo. A clear baseline also helps when a dispute arises over hold damage at the end of a charter, because on-hire and off-hire readings taken on the same TM plan can be compared directly.

Ships trading to Oxelösund 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 Oxelösund

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

Stockholm Arlanda is the usual long-haul arrival, with onward travel by train and road via Nyköping; Stockholm Skavsta, near Nyköping, is the closest airport when its European connections suit the journey. The team travels from India on Schengen visas, which we apply for as soon as the discharge date is reasonably certain. Access to the steelworks berths and the port is controlled, so the ship's agent registers the technicians with the terminal in advance and confirms any site induction required before the team can go aboard.

• 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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