Ultrasonic Thickness Measurement for Ships in Cardiff's Locked Docks

Inspection services for ships at Cardiff

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

Where a ship can be gauged at Cardiff

Almost all gauging at Cardiff happens alongside inside the enclosed docks. A general cargo ship discharging steel or timber gives access to holds as they empty, and the crew can open, ventilate and test ballast tanks while cargo work carries on elsewhere on board. Container feeders and tankers turn round faster, so their scopes concentrate on engine-room and ballast piping, the upper deck and tanks prepared before arrival. The dock estate is ISPS-controlled, and the agent obtains gate passes for the team and its equipment in advance.

Cardiff is a cargo port, not the place most ships go for a drydocking. When a renewal survey needs the hull dry, owners of short-sea ships in the Bristol Channel usually book a yard elsewhere, for example the drydocks at Swansea further west, or the larger repair yards on the Mersey and in Cornwall. Gauging at Cardiff in the weeks before that docking is a common way to settle the steel list early, so the yard can order plate and plan staging before the ship arrives. Ships waiting in the docks between charters, or laid up briefly, give longer windows still.

• Queen Alexandra Dock and Roath Dock quays — hold, tank and deck gauging on steel and forest-product ships during cargo work.
• Container terminal berth — piping, upper-deck and prepared-tank readings on feeder ships within their turnaround.
• Aggregate wharves — hopper, suction-pipe and hull plating gauging on sand dredgers between trips.
• Liquid bulk berths — deck and pipework measurements on coastal tankers under the terminal's permit rules.
• Lay-by berths inside the docks — fuller condition surveys on ships awaiting cargo or briefly laid up.
• Outer anchorage — short deck-level scopes by launch while a ship waits for the lock, weather permitting.

Port state control, ship recycling rules and the Bristol Channel fleet

Foreign ships at Cardiff are inspected by the Maritime and Coastguard Agency, which applies Paris MoU procedures through UK legislation. The older general cargo ships and bulk carriers that make up much of the Bristol Channel short-sea trade are the kind the risk-based targeting system tends to select, and a detention for structural wastage disrupts a voyage far more than a planned gauging programme would. Owners should also remember that the UK kept the EU ship recycling rules in its own law after Brexit, so ships calling here are expected to carry an Inventory of Hazardous Materials, and keeping the IHM current often prompts a wider look at structural condition.

Many of the ships calling at Cardiff fly open-registry or northern European flags and are managed from Hamburg, Rotterdam, Limassol or further afield, so the superintendent rarely sees the ship at the quay. That is where dependable readings taken by a third party earn their place: owner's condition gauging before a charter, or a pre-docking estimate that reaches the owner before the yard's quotation. Dredgers and coastal tankers trading only in UK waters are a different case, with crews who know the ship well and owners who prefer maintenance planned around a seasonal workload rather than a deep-sea charter.

Wherever a ship is outside a sulphur emission control area, the global 0.50% sulphur cap applies, and many of the ships calling at Cardiff 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 Cardiff

A gauging job at Cardiff 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.

The usual route is a long-haul flight into London Heathrow and the train from London to Cardiff Central, which leaves the team a short drive from the dock gates; Cardiff Airport and Bristol Airport offer some European connections. Technicians from India travel on UK visas, so the lead time for a first visit runs to weeks, and repeat jobs move faster once visas are held. The ship's agent arranges ISPS gate passes, confirms the lock time and, if anchorage work is planned, books a launch.

• 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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