Tian Jin Nan Jiang Underwater Engineering Co., Ltd is a long-established commercial diving and underwater inspection contractor operating from Tanggu in the Binhai New District of Tianjin, with direct access to the major terminals of Tianjin Xingang and the wider Bohai Bay. The Nan Jiang dive team operates surface-supplied air and mixed-gas equipment supported by underwater video and photographic systems, ROVs and dedicated NDT instrument kits, and provides round-the-clock mobilisation to vessels at anchorages and berths. Routine services for merchant shipping include non-docking in-water hull inspections in lieu of drydocking, propeller, rudder, sea chest and stern-frame video survey, and hull and propeller marine growth cleaning with propeller polishing for fuel-efficiency restoration on bulk carriers, container ships and tankers. Engineers also handle blanking of sea chests and overboard discharges, cofferdam installation, replacement of transducers and speed logs, and underwater repair of hull coatings using approved primers and patches. For statutory purposes, divers perform ultrasonic hatch cover tightness testing under IACS UR Z17, watertight integrity verification, hull ultrasonic thickness gauging in support of intermediate and special periodical surveys, and underwater non-destructive testing on welds, mooring chains and submerged structural members using ACFM and magnetic particle methods. The company is recognised as a service supplier by ABS, Bureau Veritas, CCS, DNV, Korean Register and Lloyd's Register, allowing the in-water survey reports it produces to be accepted by class surveyors and Chinese flag-state authorities for merchant and offshore tonnage operating at northern Chinese ports. Nan Jiang's dive team also takes on offshore wind farm O&M support, supplying surveys of monopiles, jackets, scour protection and inter-array cables for owners and operators around the northern Chinese coast.