Project 718 Tuzhong / Duchong Class
(Auxiliary Ocean Tug) / ATR (ocean rescue tug)
The Tuzhong [English = Underway] class was designed and constructed to carry out at-sea rescues, underwater rush repair, water draining, power supply at anchor and firefighting. During intercontinental missile full range flight test, she also takes up the measurement of splash down point of the warhead.
The Tuchong-class ATR was the largest vessel of this type built by the Chinese and was undoubtedly designed to augment the Navy's salvage capability. The ship, built at Shanghai Shipyard Zhonghua, was equipped with a large boom crane on the aft superstructure and was unarmed. At least one of these ships was involved inthe AWA MARU salvage operation in the Taiwan straits during the spring and sunmer of 1979.
This type of ocean tugboat had a full-load displacement of 3600 tons, a hull length of 84.9 meters, a boat width of 14 meters, and a draft of 5.5 meters. Two 10ESDZ 43 / 82B diesel engines with a power of 8600 hp (6320 kW), two-axle propulsion, a speed of 18.5 knots, and a winch capacity of 35 tons. This class of ship is not fixedly armed, but can be equipped with two 37 mm guns and has a crew of 120 people.
The first generation of our army's 9000-horsepower ocean-going rescue tugboat was a supporting ship of the 718 project and one of the 580 mission warships. In 1970, the Ministry of Six Engines instructed the China Shipyard to undertake the design and manufacture of 6615 kW (9000 hp) double adjustable propellers on a single deck, equipped with a 35-ton automatic streamer, and an ocean-going rescue tug in an unlimited navigation area. The plant is composed of workers, technicians, and using the "three-in-one" design team. General design Hu Zude, turbine design Shen Miaoqing, electrical design Bao Yican, and production supervisor Wang Mingda.
In order to make the rescue tug resistance, propulsion, stability, seaworthiness, etc. meet the requirements of use, the factory commissioned Shanghai Jiaotong University test pool to do a large number of tests, it is the factory's self-designed ship to do the most complete test.
In 1974, Hu Chuanzhi, the leader of the plant, eliminated the "WG" interference and personally grasped key projects. At that time, 1492 kW (2000 hp) of adjustable propellers was the largest in the domestic shipbuilding industry, and it was more difficult for the plant to manufacture 3357 kW (4,500 hp) adjustable propellers. Ding Xingliang, who is in charge of design work, disregarded his frail and ill health, and referred to various domestic and foreign documents and materials to formulate systematic process procedures from the various stages of design, processing, manufacturing, and installation, creating conditions for the successful manufacture of controllable pitch propellers. Wu Changfa, the leader of the turbine workshop, and Chen Jiaxiang, the leader of the casting and forging workshop, encountered various contradictions during construction, such as tight schedules, multiple technological processes, and uneven matching of blanks.
They carefully arranged the construction and maintained the nodes in every process. Hu Chuanzhi led the staff to overcome many difficulties. In order to ensure the advanced and reasonable design of the blades, the East China Institute of Water Resources is invited to carry out blade dynamic tests and measurement analysis. In order to determine the strength of the long waist-shaped hole of the oil distribution shaft, refer to the calculation formula of the Norwegian steel ship construction and classification specifications, please analyze and measure the photoelastic stress in the photoelastic test laboratory of 711 Research Institute. At the same time, polytetrafluoroethylene and bronze powder parameters are used in the oil distributor seal ring and the surface of the oil distribution shaft is nitrided to improve the new material and new technology of surface wear resistance.
The first ship T830 was launched in April 1976. After several trials in July and August of the same year, the overall performance and various mechanical equipment, electronic equipment, fire-fighting and rescue equipment were tested, and technical problems were solved one by one. In December 1977, the "Battle 17" [water displacement of 16,000 tons and main engine power of 3133 kilowatts (4200 horsepower)] was towed on the surface of Qingdao, and an automatic retraction test was conducted. Chen Huanming and Yu Yuanqin, who designed the 35-ton streamer, worked closely with the staff and 830 commanders to automatically retract the cable, which was successful and completed the same month.
In addition to the towing function, the ship also has functions of fire protection, drainage, underwater repairs, and berthing and power supply, and is responsible for the landing point measurement of the "Dongfeng 5" full-scale test. In August 1977, it was determined that two ships would be built on the basis of T830 ship manufacturing and testing. The exposed problems were revised and designed by Zhonghua Shipyard. All three ships are equipped with satellite positioning, 350 systems, underwater acoustic measurement and necessary communication equipment. The last two rescue tugboats, T154, were delivered in September 1979, and T710 was delivered in January 1980. In April 1980, three rescue tugboats participated in formations to the South Pacific to perform China's first intercontinental missile full flight test mission. Zhonghua Shipyard dispatched engineering and technical personnel and workers on each ship to provide escort services. T830, T154, and T710 are three of the six ships in the sea area intercontinental missile landing point measurement matrix, and successfully completed the mission.
Later, the three rescue tugboats served in three fleets, responsible for beach rescue and towing operations, and are now retired to the Coast Guard.
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