Thickness Gauging for Commercial Ships Docking at Rosyth

Inspection services for ships at Rosyth

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

Docks, basin and quays where Rosyth work takes place

Gauging during a Rosyth docking follows the same order as the yard. Once the dock is pumped out and the hull washed, bottom and side shell readings are taken from the dock floor and staging, sea chests are opened and measured, and the rudder and stern frame area are examined. Inside the ship, double-bottom and ballast tanks are opened, ventilated and certified safe for entry in an agreed sequence, and the team works through them with the surveyor's close-up survey programme in mind. Where plating is found below the allowable diminution, the area is marked on the steel and recorded on the class sketch the same day.

Ships waiting to enter dock, or lying afloat after undocking to finish repairs, use quays in the basin, which is a good place to complete deck, hold and piping gauging that does not need the hull to be dry. The Forth Ports berths beside the dockyard handle cargo ships, and a ship discharging there can be gauged in the normal way. Ships that call at Leith or Grangemouth before a Rosyth docking give one more opportunity, because readings taken on those calls can turn the docking specification into a firm steel list.

• Babcock drydocks — shell, double bottom, sea chest and stern area gauging during a commercial docking period.
• Dockyard basin quays — afloat repair periods for deck, hold, tank and piping work before or after docking.
• Forth Ports berths at Rosyth — routine gauging on cargo ships while they discharge.
• Lay-by berths in the basin — longer condition surveys on ships waiting for dock space or laid up.
• Earlier calls at Leith and Grangemouth — pre-docking readings that firm up the Rosyth steel list.

Port state control, class surveys and a defence site

Merchant ships calling at the Forth Ports terminal at Rosyth fall under port state control by the Maritime and Coastguard Agency, applied through UK law within the Paris MoU. In the dockyard itself the controlling documents are the class rules and the repair contract. The attending surveyor decides the extent of gauging for the survey due, the yard plans staging and access, and the owner's superintendent decides how far to go beyond the class minimum, for example in tanks that are not yet due for survey but are likely to need steel before the next docking.

The dockyard's role as a defence site affects visitors more than the work itself. Visiting technicians, particularly foreign nationals, go through the yard's security process before they are given access, which takes longer than a gate pass at a commercial quay, and the yard may restrict photography to what the job needs. For a team travelling from India this is planned alongside the UK visa, and the job documents name the ship, the dock dates and the scope so the yard can process the request. Ship recycling paperwork follows UK rules rather than the EU regulation, and ships trading to EU ports keep their Inventory of Hazardous Materials current for those calls.

Ships trading to Rosyth 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 Rosyth

A gauging job at Rosyth 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.

Edinburgh Airport lies a short drive south of the Forth crossings, which makes Rosyth one of the easier Scottish yards to reach. Teams travel from India on UK visitor visas, and because the dockyard runs its own security clearance, we start the access paperwork with the yard and the owner as soon as the docking dates are firm. The ship's agent or the owner's site representative arranges day-to-day access; accommodation is in Dunfermline, Inverkeithing or Edinburgh, depending on the length of the docking.

• 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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