Thickness Measurement for Ships at the Port of Oulu

Inspection services for ships at Oulu

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

Where ships are gauged in Oulu

Tanker work at Vihreäsaari follows the oil terminal's rules and the ship's permit system. During discharge the team can measure deck plating, the outside of cargo, ballast and fuel lines, and ballast tanks that the crew has certified safe, while cargo tank internals wait for a gas-free period or the yard. At Oritkari, container feeders and general cargo ships are measured within their working day; on a feeder the scope is cut into pieces that each fit one call, with the ballast tanks and the ice belt from inside usually done first, and decks and coamings when the cargo plan allows.

Oulu is not a docking port for large merchant ships in our planning, so renewal surveys for the ships that trade here are normally carried out at repair yards in southern Finland, elsewhere in the Baltic or further afield. Pre-docking gauging at an Oulu call gives that yard the steel quantities in advance. In winter there is little room for work at anchor, because ships move straight from icebreaker escort to the berth, so all winter gauging at Oulu is planned alongside.

• Vihreäsaari oil harbour — product tankers on the regional fuel supply run; deck, pipeline and ballast-tank gauging during discharge
• Vihreäsaari bulk berths — dry-bulk ships; hold and tank-top measurements as each hold is cleared
• Oritkari harbour — container feeders, general cargo and forest-product ships; staged gauging of tanks, decks and coamings within each call
• Nuottasaari mill harbour — ships serving the forest industry; hold and hatch cover structure gauged during loading
• Repair yards in southern Finland and the wider Baltic — in-dock verification of bottom and shell readings first taken in Oulu

Rules and winter navigation behind Oulu gauging

Port state control at Oulu is Traficom's responsibility under the Paris MoU, with inspections targeted by ship type, age and record. Tankers count among the higher-risk types, and a product tanker that trades into Oulu every winter builds up the kind of history inspectors look at: corrosion in ballast tanks, deck pipework weakened by cold and condensation, and ice-belt wear. Oil companies and terminal operators vet the tankers they use, and a vetting inspection that finds heavy wastage on deck lines or in ballast tanks can lose a ship her place on the supply run, so tanker owners here often ask for gauging ahead of a vetting.

Winter navigation is the other framework. Each season the Finnish authorities publish traffic restrictions per port, setting the lowest ice class and the minimum ship size that can count on icebreaker assistance, and at Oulu the higher ice classes are needed for the longest part of the year. Under the Finnish-Swedish Ice Class Rules the ice class rests partly on ice-belt plating thickness, which includes an allowance for abrasion and corrosion that successive winters steadily use up. Ships trading into Oulu from outside the EU also carry an Inventory of Hazardous Materials under the EU Ship Recycling Regulation, a document buyers and charterers now ask to see.

Ships trading to Oulu 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 Oulu

A gauging job at Oulu 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.

Oulu Airport, south-west of the city, is one of Finland's busiest airports, with frequent connections from Helsinki, so the team travels from India via Helsinki and drives on to Oritkari or Vihreäsaari. Finland is a Schengen country, and our technicians need Schengen visas, which we apply for as soon as the job date is firm. The ship's agent arranges ISPS passes for the harbours, and the oil terminal at Vihreäsaari runs its own safety induction. Winter itineraries carry a buffer for weather and icebreaker delays.

• 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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