Hull, Tank and Piping Thickness Measurement for Ships at Greenock

Inspection services for ships at Greenock

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

Docks, berths and anchorages for gauging on the Clyde

For a renewal survey or a docking survey, the Garvel dry dock is the place at Greenock where a hull can be gauged out of the water. The team works to the yard's programme and the agreed TM plan with the class surveyor attending, starting on the bottom shell, sea chests and stern frame while staging and lighting are in place, then moving to tanks as they are gas-freed. Because the dock is sized for ferries and coastal and short-sea ships rather than large ocean-going tonnage, bigger vessels trading to the Clyde dock elsewhere, and a Greenock call before that docking is a good time to measure the steel the yard will need to renew.

Afloat, the options depend on the ship's business. Feeder container ships at Ocean Terminal turn round in hours, so their scope is limited to what can be done during cargo work: deck plating, hatch coamings, air pipes and engine-room piping. Cruise ships allow a similar window. Ships with time to spare, waiting for a docking slot, laid up, or changing hands, can lie at a lay-by berth such as James Watt Dock or anchor off Greenock, where the agent arranges boat transfers. Those longer stays suit complete ballast tank programmes and the condition surveys that buyers and owners rely on.

• Garvel dry dock — bottom shell, sea chest, stern and tank gauging during refits and class dockings, worked to the yard programme.
• Greenock Ocean Terminal — deck, hatch coaming and piping readings on container feeders and cruise ships during their time alongside.
• James Watt Dock and other Clyde lay-by berths — full tank programmes on ships waiting for a docking slot, laid up or changing hands.
• Anchorages off Greenock — targeted deck and tank gauging by boat transfer on ships awaiting orders or a berth upriver.
• Ferry lay-over berths on the firth — sea-water piping, car-deck and void-space checks on ferries between sailings or out of season.

The Clyde's regulatory picture: MCA, recycling rules and ferries

Port state control on the Clyde is in the hands of the Maritime and Coastguard Agency, applying the Paris MoU inspection regime through UK law, and the feeder container ships and occasional bulk and general cargo ships calling here are its usual subjects. Greenock lies on the west coast, outside the North Sea emission control area that begins on the far side of Scotland. Feeders that continue to the east coast or the Continent switch fuel or rely on their scrubbers when they enter it, so their wash-water and fuel piping work under two regimes on a single rotation, which is worth remembering when the piping scope is drawn up.

Ship recycling is an unusual part of the picture here. The UK kept the EU Ship Recycling Regulation in its own law after Brexit, so UK-flagged ships must be recycled at approved facilities and carry an Inventory of Hazardous Materials, and ships of other flags calling at UK ports are expected to have one as well. With the Hong Kong Convention in force internationally since June 2025 and plans to use Inchgreen for decommissioning, owners of older tonnage on the Clyde increasingly need a clear record of their ship's condition. Ferries add a domestic dimension: UK passenger ships are surveyed by the MCA, and their operators plan steel and piping renewal around tight seasonal timetables.

Wherever a ship is outside a sulphur emission control area, the global 0.50% sulphur cap applies, and many of the ships calling at Greenock meet it with an exhaust gas cleaning system rather than compliant fuel. Scrubber wash-water piping, the overboard discharge and the hull penetration around it corrode quickly in service, especially on open-loop systems, and are worth adding to the gauging scope.

How a thickness measurement job runs at Greenock

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

Glasgow Airport is the closest international airport, with Glasgow Prestwick and Edinburgh as alternatives, and trains and roads run from Glasgow along the south bank of the Clyde to Greenock. The technicians are mobilised from India and need UK visas, so early notice of a docking date or a ship's lay-by period helps. Dry dock access is arranged with Dales Marine Services, terminal passes through Peel Ports, and boat transfers to anchored ships are booked by the ship's agent.

• 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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