Thickness Measurement for Ships in Dalian's Yards and Port

Inspection services for ships at Dalian

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

Hull gauging in Dalian: yards, terminals and ferry berths

In Dalian the work splits between yards and port. Inside the repair yards, the team gauges ships in dock and at the repair quays for renewal and intermediate surveys, steel renewal planning and re-gauging after repairs, all under the yard's permit and safety system. At the port terminals, gauging fits around cargo work on tankers, bulk carriers and container ships, and around sailing schedules on the Bohai Strait ferries, where the ferry operator's own technical staff usually decide which spaces can be released on a given night. Access for foreign technicians to yards and terminals is registered in advance, so names and passport details go to the agent or the yard before the team arrives.

Because Dalian's yards also take conversion and major repair projects, gauging is sometimes needed to decide whether a hull is worth converting or extensively repairing at all. That is a different exercise from survey gauging: wider coverage, a focus on the structure that will carry new loads, and a report the owner and their naval architect can use to judge the extent of steel work before any contract is signed.

• COSCO Shipping Heavy Industry (Dalian) — repair and conversion yard where tankers and bulk carriers dock for renewal surveys; full survey gauging, with readings fed to the steel department.
• Repair quays at the Dalian yards — work that continues after undocking, such as deck fittings, piping and tanks left until the ship is afloat.
• Dalian oil terminals — crude and product tankers serving the refineries of the north-east; deck structure, shell above the waterline and piping measured during the stay.
• Dayaowan container terminals — feeders and container ships linking north-east China with Asian and long-haul markets; deck, coaming and scrubber discharge line checks inside the berth plan.
• Bohai Strait ferry berths — car deck, ramp, bow and stern door gauging on ro-pax ferries during overnight lay-ups or planned stand-downs.
• Dalian anchorages — ships waiting for a berth or for a dock to become free; a convenient place for pre-docking readings or a buyer's thickness survey.

Inspection regimes and the northern market around Dalian

Port state control in Dalian follows the Tokyo MoU, administered on the Chinese side by the Maritime Safety Administration. For the ferries and coastal ships that never leave Chinese waters, oversight comes from the flag administration and class instead, but the structural points of interest are much the same: deck and car deck plating, hull openings and their closing appliances, ballast tanks and piping. Scrubber-fitted ships entering Dalian are also subject to China's domestic emission control rules, which limit open-loop discharge in certain waters.

Winter shapes the northern market. When sea ice builds up in Liaodong Bay, ships trading to the ports at the head of the bay have to work through it, and owners look closely at the forward shell, waterline plating and sea chests when those ships come in for survey. Dalian's yards are the natural place to inspect that structure after a hard winter. For large tankers and bulk carriers, the attraction is dock capacity close to the northern trades: a ship that discharges in the Bohai can move straight into a Dalian yard, which keeps the ballast passage short and makes pre-docking gauging during the last discharge call straightforward.

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

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

Flights into Dalian Zhoushuizi International Airport normally connect through Beijing or Shanghai. Each repair yard issues its own gate passes and runs a safety induction before work starts, organised with the owner's representative on site; port terminals and ferry berths need passes obtained by the agent. Because the team comes from India, Chinese business visas and the invitation letters behind them are prepared as soon as the dock date or ferry stand-down is confirmed, which leaves time to complete them before mobilisation.

• 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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