Ship Gauging in Orkney: Scapa Flow Anchorages, Flotta and Kirkwall

Inspection services for ships at Orkney

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

Where ships are gauged in Orkney

Orkney has no drydock for seagoing ships, so almost all thickness measurement here happens afloat. In Scapa Flow that means anchorage work: the agent arranges a launch through the harbour authority's marine services, the team boards by pilot or accommodation ladder, and the steadiness of the Flow allows longer working days on board than an open anchorage would. Tankers waiting on lay-can dates, ships between STS operations and accommodation units in for maintenance are the main candidates. Tank entry depends on the ship's own gas-freeing and permits, so the cargo and ballast plan is discussed with the master before the team mobilises.

Alongside work is concentrated at Hatston and Kirkwall piers and at Stromness, where ferries, cruise ships during their calls, and the islands' tugs, pilot boats and workboats lie at predictable times. Ferries and harbour craft that need docking go to yards on the Scottish mainland or further afield, and a gauging visit in Orkney a few weeks before is the practical way to give the yard a measured steel estimate. Accommodation units and project vessels that moor in the Flow rather than on a quay are reached by launch in the same way as the tankers.

• Scapa Flow anchorages — deck, piping and ballast tank gauging by launch on tankers waiting on lay-can dates or between STS operations.
• Flotta terminal — external deck and piping UT on loading tankers, within the terminal's permit and hazardous-area rules.
• Accommodation unit moorings in the Flow — pontoon, column and deck gauging on semi-submersibles during maintenance between contracts.
• Hatston Pier, Kirkwall — car-deck, void-space and sea-water piping work on ferries and cruise ships during their calls.
• Stromness harbour — hull and deck checks on ferries, renewable-energy support vessels and workboats alongside.
• Kirkwall harbour — gauging on inter-island ferries, tugs, pilot boats and fish-farm workboats between duties.

Ship-to-ship transfers, port state control and island regulation

Foreign-flagged ships in Orkney waters are subject to port state control by the Maritime and Coastguard Agency, which continues to apply the Paris MoU under UK legislation. STS operations bring a second layer: in UK territorial waters, cargo transfers between ships are confined to harbour areas holding an approved transfer licence, and Orkney Islands Council's licence for Scapa Flow sets the procedures, weather limits and pollution-response arrangements both ships must follow. Charterers and the oil majors who vet the tankers involved look closely at hull and deck condition, and an STS operation is not the time to discover a leaking deck line.

The islands' own fleets sit under different rules. UK-flagged passenger ferries are surveyed by the MCA for their passenger certificates, fish-farm workboats fall under UK small-vessel codes, and the accommodation units in the Flow are mobile offshore units with their own class and flag requirements. Ballast water is also managed locally: Orkney Islands Council adopted a ballast water management policy for the Flow, reflecting concern about invasive species in waters with important fisheries and fish farms. For an owner, the practical consequence is that the reason for gauging, and the report format needed, can differ from one vessel to the next within a single harbour.

Ships trading to Orkney 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 Orkney

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

Kirkwall Airport has Loganair flights from Aberdeen, Edinburgh, Glasgow and Inverness, and the team usually reaches Orkney that way after an international arrival in Scotland. NorthLink ferries from Aberdeen to Kirkwall and from Scrabster to Stromness are useful when equipment travels by road or when flights are weather-bound. The technicians travel from India on UK visas, so early notice of the ship's expected time in the Flow matters. Launches, pier access and any terminal passes are arranged through the ship's agent and the harbour authority.

• 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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