Ultrasonic Thickness Measurement for Fishing, Research and Offshore Vessels in Scheveningen

Inspection services for ships at Scheveningen

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

Quays and docking options for Scheveningen vessels

Gauging at Scheveningen is mostly done alongside. A trawler or offshore vessel lying at the quays of the First Harbour can be gauged in its tanks, voids, machinery spaces, decks and accessible structure, with the crew emptying and ventilating tanks in turn and the engine room giving access to sea-water piping and the sea chest areas from inside. Shell plating above the waterline can be reached from the quay or the deck; below it, readings are taken from inside the hull where the structure allows. Insulated fish holds and freezer spaces limit internal access, so readings concentrate on the tanks and voids that border them.

For a full hull programme with the bottom exposed, vessels based here generally go to a dock or slipway elsewhere. The repair yards of the Rotterdam area, including Schiedam, are close by, and fishing and offshore owners also use repair facilities at IJmuiden and Den Helder and yards in Belgium and Germany. A scope split between Scheveningen and the docking yard works well: internal readings during a stay alongside, and external bottom readings once the vessel is out of the water. Owners of trawlers that land their catch abroad and return to Scheveningen only for maintenance should tell us their lay-over dates early, as these are the realistic windows.

• First Harbour fishing quays — tank, void, deck and engine-room piping gauging on pelagic trawlers and cutters between trips.
• First Harbour offshore berths — deck, crane and A-frame foundation, tank and piping readings on survey and support vessels between projects.
• Third Harbour — gauging on research and government vessels during maintenance periods alongside.
• Lay-over berths used during maintenance periods — longer owner's condition and pre-purchase surveys on idle vessels.
• Docks and slipways in the Rotterdam area and along the coast — external bottom readings to complete a programme started alongside.

Fishing-vessel safety rules, port state control and offshore charters

Large fishing vessels sit under a different safety regime from cargo ships. Dutch-flagged fishing vessels of 24 metres and over follow the EU safety rules for fishing vessels, with surveys by the flag administration or a recognised organisation acting for it, and many of the big pelagic trawlers are also classed. Paris MoU port state control is aimed at the merchant ships that use the harbour, such as offshore and survey vessels under foreign flags, rather than at the fishing fleet. For trawler owners, the reasons to gauge are therefore class and flag surveys, insurers' expectations and the resale value of a vessel whose hull has spent years in hard service.

Offshore vessels answer to a different audience. Charterers in the wind and survey markets inspect vessels before and during contracts, often under industry schemes such as OVID, and they look for evidence of structural condition around cranes, A-frames and deck equipment foundations, where loads concentrate. EU rules apply to the merchant vessels among them in the usual way, including the Inventory of Hazardous Materials for ships calling at EU ports; fishing vessels sit outside the EU ETS for shipping, and many offshore vessels fall below its thresholds. A record of thickness readings kept up to date between dockings answers a charterer's questions faster than a promise to check at the next yard visit.

Ships trading to Scheveningen 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 Scheveningen

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

Amsterdam Schiphol and Rotterdam The Hague Airport are the nearest airports, and from Den Haag Centraal the harbour is reached by tram or road. The harbour company controls movements and the quays, and the vessel's agent or owner arranges the team's access to the berth. Technicians are mobilised from India on Schengen visas, so lay-over dates should be shared as soon as the fishing or charter plan allows; a trawler's return can move with the catch, and we keep travel flexible around the owner's latest estimate.

• 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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