Ship Thickness Measurement at Grangemouth on the Upper Forth

Inspection services for ships at Grangemouth

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

Where gauging fits in at Grangemouth

Inside the enclosed docks, ships lie at quays with road access, so the team can bring gauges, lighting and ventilation equipment to the gangway without fuss. On a feeder container ship the realistic scope during a call is deck plating, hatch coamings and covers, deck fittings and their foundations, and ballast tanks the crew have opened and ventilated before arrival. General cargo and bulk ships discharging over several days allow hold gauging as each hold is emptied. Engine-room piping, including sea-water cooling and fuel lines, can usually be measured during any call because it does not depend on cargo operations.

Tankers at the terminal jetties are a different matter. Cargo tanks cannot be entered until they have been gas-freed, and terminals restrict what equipment comes aboard, so cargo-area gauging on a product or chemical tanker is normally planned for a lay-by period, a repair spell or the docking itself. When a docking is due, ships from Grangemouth either drop down the Firth to the Babcock yard at Rosyth or sail for yards in Poland, the Netherlands or elsewhere in northern Europe, so a Grangemouth call is often the place to take pre-docking readings.

• Container berths in the enclosed docks — deck, hatch cover, coaming and ballast tank gauging on feeders during a call or across several calls.
• General cargo and bulk berths — hold and tank gauging as discharge empties each space.
• Lock and lay-by berths — longer scopes on ships waiting for a slot or held in port between voyages.
• Terminal jetties on the river — piping and deck checks within terminal rules; cargo tanks only once gas-freed.
• Rosyth drydocks down the Firth — full renewal-survey scopes when a ship moves on for docking.

Port state control, tanker vetting and emissions rules

Port state control at Grangemouth is carried out by the Maritime and Coastguard Agency within the Paris MoU, and the UK, outside the EU, runs its own ship recycling regime in place of the EU regulation. Tankers and gas carriers also face the oil companies' and terminals' vetting systems, and for a chemical or product tanker a SIRE inspection report that mentions wasted deck lines, corroded vent heads or doubtful ballast tank coating will raise questions at the next fixture. Current readings on deck piping, vent and air pipes and ballast tank structure are the simplest way to answer those questions with figures rather than assurances.

The feeder trade between Grangemouth and continental hubs sits squarely inside European emissions rules as well. Half of the emissions on each voyage between Grangemouth and an EU port fall under the EU Emissions Trading System, and FuelEU Maritime counts the energy used on those voyages in the same proportion, which keeps feeder operators focused on hull condition and fuel consumption. Ships on these rotations call at EU ports every week, so they carry an Inventory of Hazardous Materials for EU purposes as a matter of course. The refinery's switch to an import terminal has not removed tanker calls; it has changed what they carry and where it comes from.

Ships trading to Grangemouth 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 Grangemouth

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

Edinburgh Airport is the nearest international airport, and Glasgow Airport is an alternative; both are within driving distance of Grangemouth. The team needs UK visitor visas, so the expected call date is requested early, and for feeder ships on fixed rotations the visit can be planned weeks ahead. The ship's agent arranges port passes through the ISPS-controlled gates, and work on a tanker at a terminal jetty also needs the terminal's permission and any induction it requires.

• 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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