Ultrasonic Thickness Gauging for Ferries and Cargo Ships in Portsmouth

Inspection services for ships at Portsmouth

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

Where ships can be gauged in Portsmouth Harbour and the eastern Solent

Most gauging happens at the ferry linkspans and lay-by berths of the international port. A ferry lying overnight gives several hours of steady access: ballast and fresh-water tanks pumped out and ventilated by the crew, voids and cofferdams opened, and vehicle decks clear of traffic so ramps and deck plating can be reached. Work stops when loading begins, so the plan sets out which tanks are done on which visit. Cargo ships at the port's quays are gauged during discharge, with each hold worked as it empties and the hatch covers read while they are open.

The drydocks inside Portsmouth Harbour belong to the naval dockyard, so merchant ships calling here generally go elsewhere for a docking, often to a yard on the Continent or in Spain for the Biscay ferries. That makes Portsmouth a place for in-service and pre-docking gauging rather than for renewal steelwork. Ships waiting to enter can anchor at Spithead or off St Helens on the Isle of Wight, where boarding by launch is possible in settled weather, but a berth is usually only hours away and few owners choose to work at anchor when the quay is so close.

• Continental ferry linkspans — vehicle-deck, ramp and hinge inspection on ro-pax ferries between sailings, timed around loading.
• Lay-by and overnight berths at the international port — staged ballast tank and void gauging over consecutive visits ahead of a winter refit.
• Passenger terminal berth — piping, tank and exterior structure readings on cruise ships during a day call.
• Cargo quays — hold, hatch-cover and tank-top readings on reefer and general cargo ships as cargo comes out.
• Gunwharf and the Isle of Wight ferry berths — shell, deck and piping checks on car ferries and fast craft during maintenance periods.
• Spithead and St Helens anchorages — launch-borne deck and air-pipe readings on ships held outside the harbour.

Port state control, emissions rules and ferry regulation at Portsmouth

Foreign-flagged ships calling at Portsmouth are inspected by the Maritime and Coastguard Agency, which applies Paris MoU procedures under UK law. For the ferries, a larger regulatory driver is the EU's climate package: voyages between Portsmouth and French or Spanish ports bring half their emissions under the EU Emissions Trading System and half their energy use under FuelEU Maritime, for ships of 5,000 gross tonnage and above. Operators have answered with newer LNG-fuelled and hybrid ships alongside older tonnage fitted with scrubbers, and each brings its own inspection points, from fuel-tank cofferdams to wash-water lines.

Ro-pax ships also live with closer scrutiny of their watertight and weathertight integrity than most cargo ships, because of stability lessons the industry learned the hard way on open vehicle decks. Bow doors, inner ramps, stern doors and their securing arrangements are examined by class, flag and the operator's own superintendents, and wastage or cracking around them is treated seriously. Gauging that tracks plate thickness at ramp hinges, door frames and the vehicle-deck plating nearest the ramps gives the operator evidence to plan renewals rather than react to a surveyor's finding.

Ships trading to Portsmouth 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 Portsmouth

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

Heathrow and Gatwick are the usual arrival airports, with trains from London to Portsmouth Harbour station or a drive down the A3; Southampton Airport is closer but has fewer international connections. The international port, the naval-controlled harbour and the ferry berths are all secured areas, so the ship's agent or the operator's port team arranges passes against each technician's passport before the visit. Technicians from India need a UK visa, so we fix the lay-overs we will use well in advance and keep the dates agreed with the operator.

• 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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