Hull and Hold Gauging for Ships Serving the Raahe Steel Works

Inspection services for ships at Raahe

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

Gauging sites at the Raahe raw-material and steel berths

On the raw-material side, bulk carriers are gauged as they discharge. Ore pellets and coal leave fine abrasive dust and damp residues that hide pitting, so reading points are cleaned locally, and the lower parts of hold frames, brackets and hopper plating, where the grab works hardest, get a closer reading pattern. Topside and double-bottom tanks are entered once the crew has issued the enclosed-space permit. On the steel side, holds are measured before the stow is built, with particular attention to tank top plating under the coil rows and to the frames, brackets and lashing points that take cargo loads at sea.

We do not plan dockings in Raahe; ships on this trade dock at repair yards elsewhere in the Baltic, chosen by the owner. The useful role of Raahe comes earlier in the cycle: a ship that calls regularly can be measured at one or two calls before her docking, so the yard knows how much tank top, frame and ballast tank steel to prepare. Work at anchor is not part of our Raahe planning, because ships berth directly and in winter arrive under icebreaker escort.

• Raw-material berths at Lapaluoto — bulk carriers discharging iron ore pellets, coal and limestone; hold, hopper and tank-top gauging as each hold empties
• Steel loading quays — general cargo, multipurpose and open-hatch ships; tank-top and hold-frame gauging before the steel stow is built
• Ballast tanks and double bottoms on both fleets — measured under the ship's permits during the cargo stay
• Hatch covers and coamings — gauged on steel carriers, where weathertightness protects a cargo that rusts quickly
• Repair yards elsewhere in the Baltic — in-dock follow-up of readings first taken at Raahe

Inspection, ice class and the steel trade's demands

Raahe is a Finnish port, so port state control is carried out by Traficom under the Paris MoU, and bulk carriers are among the ship types the regime targets more closely. Ice class is a practical condition of trade here: the Finnish winter traffic restrictions decide which ships may call and be assisted by icebreakers, and a ship whose ice belt has thinned below the class requirement risks the notation she needs for winter contracts. Bulk carriers fixed for Raahe through the winter are therefore checked by charterers for ice class, and owners are better placed with recent ice-belt readings to hand.

Steel receivers are particular about cargo condition. Hot-rolled steel that gets wet in the hold rusts and leads to claims, so the ships that load at Raahe need weathertight hatch covers, sound coamings and no leaks from ballast tanks or air pipes into the holds. Gauging of hatch cover plating, coamings and the hold boundaries with the ballast tanks addresses exactly that. On the raw-material side the ESP rules apply to the bulk carriers, so their renewal and intermediate surveys bring the full set of transverse sections and close-up survey requirements, and a Raahe discharge is a good place to begin that work.

Ships trading to Raahe 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 Raahe

Most of the work on a Raahe job happens before the team boards: scope, plan and access are settled first, so the time on board goes on measurement.

Raahe has no scheduled airport, so the team flies from India to Helsinki and on to Oulu Airport, then drives south along the coast to Raahe. Our technicians travel on Schengen visas, and we begin the application as soon as the ship's arrival window is clear. Access to the berths at Lapaluoto and to the steel works' areas is arranged through the ship's agent, and the works' own safety rules and induction apply to everyone entering. In winter we allow a margin for road conditions 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.

Related