Thickness Gauging for Ferries and Other Ships at Holyhead, Anglesey

Inspection services for ships at Holyhead

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

Where and when ships can be gauged at Holyhead

Work on the ferries is done at their berths, during layovers agreed with the operator's technical department and the master. Vehicle decks are gauged when they are empty between discharge and loading, following a plan that divides each deck into areas small enough to finish in one window. Ballast tanks, voids and engine-room piping are often easier, because the crew can prepare them in advance and vehicle movements do not affect them. Ramps, bow visor and stern door structure, with their hinges and locking devices, can be checked by magnetic particle inspection when they are open and out of use.

Holyhead has no drydock able to take the ferries, so refits and docking surveys happen at yards elsewhere in Britain, in Ireland or on the continent. Gauging at Holyhead before the ship leaves for refit lets the operator send the yard a list of plating and piping to renew instead of discovering it on arrival. The inner harbour has quays for fishing vessels and workboats, where routine hull and deck gauging alongside is straightforward, and ships sheltering in the bay can be visited by launch when the sea allows it.

• Ferry berths — vehicle deck, ramp and ballast tank gauging on Dublin ro-pax ships during layovers.
• Extended or overnight layovers — larger tank and piping programmes planned with the operator's technical team.
• Cruise berth — targeted checks on visiting cruise or expedition ships by prior arrangement.
• Inner harbour quays — hull and deck gauging on fishing vessels, workboats and small offshore craft.
• Holyhead Bay inside the breakwater — launch-borne deck scopes on ships sheltering from weather.

Ferry regulation, emissions and port state control at Holyhead

Ro-pax ferries on the Dublin route work under a dense set of rules: SOLAS and the passenger-ship stability requirements, flag-state surveys by the ships' registries, class surveys, and port state control by the Maritime and Coastguard Agency at Holyhead and by the Irish maritime authorities at the other end, both following Paris MoU procedures. Because the ships carry passengers, inspectors take ramps, doors and vehicle decks seriously, and operators keep detailed maintenance records. Readings that show where vehicle deck plating, ramp structure or ballast tank boundaries are thinning help an operator meet those expectations and avoid unplanned time out of service.

Since 2024 the EU Emissions Trading System has covered half of the emissions on voyages between an EU port and a non-EU port, which takes in every crossing between Holyhead and Dublin by ships of 5,000 gross tonnage and above. That has sharpened the focus on fuel efficiency and on whether to keep older ferries or replace them. Ships visiting UK ports are also expected to carry an Inventory of Hazardous Materials under the ship recycling rules Britain kept after leaving the EU. Holyhead sits within the Anglesey Freeport designated in 2023, and energy projects in the Irish Sea may bring more offshore vessels through the port in the years ahead.

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

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

Holyhead is reached through Manchester Airport or Liverpool John Lennon Airport, then by rail along the North Wales coast or by road on the A55. London Heathrow is an alternative, with direct trains from London to Holyhead. The team travels from India on UK visas, and because ferry layovers can be planned weeks ahead, visas and travel are arranged in good time. Access to the ferry berths is through the port's security, with passes arranged by the operator or 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.

Related