Thickness Measurement for Ferries and Cargo Ships at the Port of Larvik

Inspection services for ships at Larvik

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

Where ships are measured in and around Larvik

The ferry berth, the container quay and the general cargo and bulk quays are the working locations. On the ferry, the chief engineer releases one system at a time during turnarounds and the team measures it while passengers and vehicles move above; car-deck work follows the vehicle flow and stops when loading starts. On cargo ships, measurement goes on alongside cargo work, with the team kept clear of crane and grab operations. Stone and aggregate cargoes leave dust and impact damage in the holds, so the tank-top usually needs sweeping before readings can be taken, and the ship is asked to plan for that as the hold empties.

Larvik is a cargo and ferry port rather than a docking port. The ferry and the cargo ships take their dockings at yards elsewhere on the Norwegian coast, in Denmark, in Poland or further afield, and readings from Larvik serve as a pre-docking estimate for those yards. Ships with a longer wait between cargoes can sometimes lie at a quay for a day or two, which is the best chance for ballast tank entry, since tanks can be emptied, ventilated and certified without competing with cargo handling.

• Ferry terminal near the town centre — engine-room piping and car-deck plating on the Hirtshals ro-pax ship, released system by system during turnarounds.
• Container quay — scrubber lines, deck plating and void spaces on feeders while containers are worked.
• Bulk and general cargo quays — tank-top and hopper gauging on stone and aggregate carriers as each hold is cleared and swept.
• Lay-by time at the cargo quays — ballast and double-bottom tanks on ships waiting between cargoes, once tanks are certified for entry.
• Docking yards chosen by the owner — completion of renewal survey gauging after pre-docking readings taken in Larvik.

Port state control and cargo wear at Larvik

Foreign ships at Larvik are inspected by the Norwegian Maritime Authority under the Paris MoU. Short-sea general cargo and bulk ships calling here are often older tonnage, and port state control officers look closely at hatch covers, coamings, air pipes and ventilators, where wastage on these ships tends to show first. A detention, or a deficiency that class must clear before sailing, gives the owner little time, and readings taken at the berth can settle whether a temporary repair is enough to reach the next yard. Older short-sea ships trading to EU ports need an up-to-date Inventory of Hazardous Materials as well, which owners often renew at the docking where the steel work is done.

The wear that matters at Larvik comes from the cargo. Stone blocks are heavy and concentrated, and both blocks and crushed aggregates are loaded and discharged by grab, crane and front loader, which dents and abrades tank-top plating, scrapes hopper slopes and damages the lower parts of hold frames. Over years that mechanical wear combines with corrosion, especially where water collects at bilge wells and along the tank-top edges. Ferry car decks see a different load pattern, with heavy freight trailers on fixed lanes and lashing points loaded and released on every crossing, and fatigue cracking around supports and doublers is as much a concern there as thinning.

Ships trading to Larvik 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 Larvik

A gauging job at Larvik 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.

Sandefjord Airport Torp, a short drive from Larvik, has European and domestic flights, and Oslo Airport at Gardermoen is the alternative, with onward rail travel via Oslo on the Vestfold line. Passes for the ferry terminal and cargo quays are arranged by the ship's agent under ISPS, and the ferry operator adds its own safety briefing for work in passenger and vehicle areas. Larvik is in the Schengen area, so each technician from India needs a Schengen visa, and because ferry and feeder schedules are fixed, jobs here can usually be planned with a comfortable lead time.

• 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