Ultrasonic Thickness Gauging for Ships Calling at the Port of Leith

Inspection services for ships at Leith

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

Where ships are gauged in Leith and on the Forth

The bulk of gauging at Leith is done alongside inside the enclosed docks. The crew or the stevedores clear a hold, it is ventilated and declared safe, and the team works through frames and plating in sequence while other holds carry on discharging. Ballast tanks are opened under the ship's own entry procedures, and any fuel or cargo tank needs a gas-free certificate first. Because the docks are impounded, shell readings near the waterline can be taken from a work boat or a cherry picker on the quay without the water level shifting during the day.

For a docking, ships trading to the Forth generally look to the Babcock docks at Rosyth, a short way upriver, or to a yard across the North Sea. A Leith call before that docking is a sensible moment to take pre-docking readings, so the steel list travels to the yard with the repair specification instead of being discovered once the dock is pumped out. Laid-up ships in the docks give the longest windows of all, with time to open every tank in turn.

• Enclosed dock berths inside the sea lock — hold, tank and deck gauging during discharge or a repair spell.
• Offshore wind berths — deck, crane foundation and ballast tank gauging between installation campaigns.
• Cruise berths in the docks — piping and tank checks during a summer turnaround, when time allows.
• Lay-up berths in the enclosed docks — full condition surveys on idle offshore and cargo ships.
• Outer Firth anchorages — short targeted scopes by launch on ships waiting for a berth or the lock.
• Rosyth drydocks upriver — follow-on gauging when a ship moves from a Leith call to a docking.

Port state control, UK rules and the Forth trades

Ships calling at Leith come under port state control by the Maritime and Coastguard Agency, which continues to target and inspect foreign ships under the Paris MoU even though the UK has left the EU. Inspectors begin with what the crew can show them, but corroded air pipes, wasted deck plating around hatch coamings and leaking ballast lines are the kind of visible defects that turn a routine inspection into a detention. Owners whose ships trade regularly to the Forth therefore have an interest in keeping deck structure and piping in a condition that survives a walk-round, and current thickness records help answer an inspector's questions when they arise.

Outside the EU, the UK applies its own ship recycling regulations instead of the EU regulation, but a ship trading between Leith and continental ports still needs an Inventory of Hazardous Materials to call at EU ports, and half of the emissions on a voyage between Leith and an EU port fall under the EU Emissions Trading System. For the wind vessels the closer scrutiny comes from the developers and contractors who charter them, whose vessel audits ask for evidence of deck, tank and foundation condition before a campaign begins.

Ships trading to Leith 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 Leith

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

Edinburgh Airport is the obvious arrival point, with connections through London and other European and Gulf hubs, and Leith is reached by road across the city. Teams travelling from India need UK visitor visas, so we ask for the expected call as early as possible and keep visas valid for owners who use the Forth often. The port runs under ISPS controls, so the ship's agent requests gate passes and confirms the berth and lock time; for wind vessels the charterer may also require a site induction before the team boards.

• 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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