NGC Marine-Supplied Main Propulsion Gearbox for 38,168 cubic meters Trailing Suction Hopper Dredger Successfully Passes Ship Survey and Customer Acceptance Test
On March 19, 2025, the main propulsion gearbox supplied by Nanjing High Accurate Marine Equipment Co., Ltd. (NGC Marine) passed the complete machine acceptance test by the China Classification Society (CCS) and was jointly approved by the Tianjin Dredging Co., Ltd, Wartsila and Zhenhua Shipyard. Due to its large size, the gearbox will be shipped disassembled. By now, the painting and packaging have been completed and ready for delivery to the shipyard in the coming days.
The gearbox will be installed on the Tongjun, a 38,168 cubic meters railing suction hopper dredger (TSHD) under construction for the China Communications Construction Company (CCCC) Tianjin Dredging Co., Ltd. Equipped with a hybrid power system, the vessel measures 195 meters in overall length, 38.5 meters in width, and 18 meters in depth. With a range of 12,000 nautical miles and 25 days of endurance, it is capable of world-wide voyage and achieving a maximum dredging depth of 120 meters. Upon completion, it will rank as the largest TSHD in Asia and the third largest globally by hopper capacity.
NGC Marine independently completed the whole design and manufacture of the main propulsion gearboxes, which feature a single-input, dual-output vertical arrangement structure. The vessel's propulsion system adopts a twin-engine, twin-propeller configuration, with the entire system packaged by Wartsila The input diesel engines deliver 14,400 kW each at 600 rpm, while the gearbox's PTO output reaches 13,000 kW. To meet the severe working conditions of dredger, the technical team from NGC Marine address challenges such as structural complexity, high reliability requirements, compact installation space and high integration difficulties through advanced engineering methods including KISSsoft gear strength calculations, finite element analysis (FEA) by CAE software and 3D modeling. Meanwhile, combined with almost twenty years of experience in the design of dredging transmission equipment, the reliability, maintenance and safety of the gearboxes were also fully reviewed and verified. During the running test, the gearbox performed stable operation, meeting all design specifications and earning praise from Tianjin Dredging Co., Ltd, CCS surveyors, Wartsila and Zhenhua Shipyard.
The technical expertise of NGC Marine in marine propulsion system and specialized dredging equipment has earned high trust and acclaim from domestic and international customers. Over the past decade, NGC Marine has supplied nearly 60 sets of integrated dredging transmission equipment and its propulsion system for large TSHDs, cutter suction dredgers (CSDs), and other dredging vessels to clients including the Tianjin, Shanghai, Guangzhou, and Yangtze River Dredging Co., Ltd, as well as Haixin Shipping Heavy Industries Co., Ltd.