Pre-Docking and In-Dock Thickness Measurement for Ships at Duqm

Inspection services for ships at Duqm

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

Where Gauging Is Done at Duqm

Asyad Drydock is the centre of gauging work at Duqm. Its dry docks give full access to the underwater hull and, once tanks are gas-freed and ventilated, to cargo, ballast and fuel tanks without the time pressure of a cargo call. The yard's afloat repair berths, used before or after docking, suit tank and deck gauging that does not need the ship out of the water. We work within the yard's permit-to-work system and coordinate with the yard's production team and the class surveyor's attendance, so that readings are ready when the surveyor walks each space.

Outside the yard, the Port of Duqm's commercial and liquid berths handle cargo ships and product tankers loading at the refinery, and the anchorage holds ships waiting for docking or a berth. Pre-docking gauging at anchorage is practical in calm weather, but launch transfers become difficult in the southwest monsoon, so anything that depends on boats should be done earlier in the voyage or deferred until the ship is alongside. Duqm is remote, so our technicians travel with their own gauges, probes, couplant and calibration blocks rather than relying on local supply.

• Asyad Drydock, dry docks — bottom plating, bilge strakes, sea chests, rudder, stern frame and tank gauging during the docking period
• Asyad Drydock, repair berths — afloat gauging of cargo, ballast and fuel tanks, decks and piping before or after the ship enters dock
• Duqm anchorage — pre-docking gauging to confirm the steel estimate while the ship waits for its dock, weather permitting
• Port of Duqm liquid berths — deck, piping and accessible tank gauging on product tankers loading refinery cargo
• Port of Duqm commercial berths — hold and deck gauging on bulk, general cargo and container ships during their call
• Earlier ports on the voyage — gauging at Sohar, Salalah or a Gulf port before the ship sails for Duqm, when the steel list is needed early

Regulation and Owner Context for Ships Docking at Duqm

Oman applies port state control under the Riyadh MoU, though for a ship in dock the more immediate authority is class: the renewal survey defines the gauging extent, and the attending surveyor decides where additional readings are needed when substantial corrosion turns up. For ESP ships, meaning oil tankers, bulk carriers and chemical tankers, the third renewal survey and later ones bring extensive gauging of cargo and ballast tank structure, and that is the docking where preparation pays off most. The Arabian Sea is outside any emission control area, so the 0.50% global sulphur cap applies, and docking is the usual time for scrubber maintenance and the overboard piping inspection that goes with it.

The ships that dock at Duqm come from a wide catchment: Gulf, Red Sea and Indian Ocean trades, with owners and managers in the Gulf states, India and further afield. For them, Duqm is one option alongside yards in the UAE, Bahrain and elsewhere, and the choice often turns on dock availability and the ship's route. Gauging ahead of arrival lets an owner compare yards on the same measured scope, and gives the technical superintendent a firm basis for the docking budget and off-hire planning. For hull gauging at Duqm, that preparation is what turns a yard estimate into a work list.

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

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

The usual route is through Muscat International Airport, then a domestic flight to Duqm Airport or the long drive south through Al Wusta. Asyad Drydock and the Port of Duqm control access through their own security; the yard or the ship's agent arranges passes for each technician and their equipment, and launches for anchorage work. Indian technicians travel on Omani business visas, applied for as soon as the docking date is fixed. Because dockings are booked well ahead, the visa lead time rarely constrains the job, and we confirm accommodation in Duqm at the same time.

• 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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