Ship Thickness Measurement at the Port of Sheerness and the Medway

Inspection services for ships at Sheerness

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

Gauging berths and windows at Sheerness

Sheerness is a cargo port rather than a repair port, so gauging here is done afloat during cargo calls. At the vehicle berths the team works on decks the stevedores have cleared, with the ship's crew providing lighting and safe access to hoistable decks, and moves deck by deck behind the discharge. On ro-ro freighters the stern ramp, its hinges and the main vehicle deck take the hardest wear, and they are best inspected in the gap between unloading and loading. On refrigerated cargo ships, deck and machinery-space work fits around the cargo, because the cargo spaces must stay closed and cold until they are worked.

Forest products berths give the longest working time. Holds empty over the course of the discharge, and tank tops, frames and hatch covers can be gauged as each hold is cleared. Ships waiting in the estuary for a berth or a tide sometimes anchor off the Medway, and launch-borne deck work can be arranged through the agent in fair weather, although the estuary's short, steep sea in a northerly blow ends that option quickly. For docking, ships on these trades generally go to yards on the near Continent or elsewhere in Britain, and the readings from a Sheerness call travel with the specification.

• Vehicle berths: car deck plating, hoistable deck supports and internal ramp gauging, with crack detection, on car carriers between discharge and loading.
• Ro-ro berths: stern ramp, hinge and main vehicle deck structure on trailer ferries during the turnaround.
• Fresh fruit terminal: deck structure, hatch covers and sea-water cooling piping on refrigerated cargo ships, worked around cargo operations.
• Forest products and steel berths: hold-by-hold tank-top, frame and hatch cover gauging during discharge.
• Thames Estuary anchorages: short launch-borne deck and air-pipe scopes on ships waiting for a berth, weather permitting.

Port state control, vehicle-carrier scrutiny and the car trade

The Maritime and Coastguard Agency carries out port state control at Sheerness, and the UK continues to apply the Paris MoU through national regulations. Vehicle carriers have drawn particular scrutiny in recent years after serious fires that started in cargo on car decks, and inspectors, insurers and charterers now look closely at the condition of decks, ramps, fire boundaries and fixed fire-fighting pipework. Wasted ramp structure or a corroded fire main on a car carrier is a finding that all of them take seriously, and current thickness and crack-detection records are the most direct answer to it.

The car trade has its own commercial pattern. Many car carriers are chartered by vehicle logistics companies on long contracts, and a large number of new ships have joined the trade since the early 2020s, often with dual-fuel engines, while older ships run on beside them. On the older ships, decks and ramps have carried countless vehicle movements, and owners need to know where deck plating and stiffeners are thinning before an intermediate or renewal survey, or before a charter ends. Fruit trades rely on refrigeration plant whose sea-water cooling lines corrode steadily and are simple to check while the ship works cargo.

Ships trading to Sheerness 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 Sheerness

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

Teams usually fly into London Heathrow, Gatwick or London City and travel to the Isle of Sheppey by road, or by rail with a change at Sittingbourne for the branch line to Sheerness-on-Sea. The technicians travel from India and need UK visas, which take longer to arrange than a car carrier's rotation, so we work from the published schedule and book the call we will meet well ahead. Port access is controlled; the ship's agent requests passes from the port against each technician's passport and confirms the berth.

• 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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