Type 744 buoy tender

Type 744 buoy tender and its derivatives with NATO reporting name Yannan (延南) class is a class of Chinese buoy tender]] that is in service with the People's Liberation Army Navy (PLAN) and Chinese civilian governmental establishments.

Type 985
The origin of Type 744 can be traced back to Type 985 buoy tender, which is first purpose built buoy tender in Chinese inventory, Type 985 is designed to be the replacement of earlier buoy tenders converted from former US Navy net laying ships. In the early 1980s, maritime navigational responsibility was transferred from PLAN to Ministry of Transport of the People's Republic of China (MOT) by the order of Chinese government, and Type 985 was among the equipment transferred from PLAN to MOT and remained in civilian service since. Specification:
 * Displacement (t): 1120
 * Length (m): 65.22

Type 994
Type 994 buoy tender is the larger cousin of the smaller Type 985 buoy tender, from which it is developed from. Type 994 is the enlarged version of Type 985, and like Type 985, all units of this class were transferred to civilian service under MOT when in the early 1980s, maritime navigational responsibility was transferred from PLAN to MOT under the order of the Chinese government. Specification:
 * Displacement (t): 1750

Type 744
Type 744 buoy tender is a development of earlier Type 994buoy tender, with design modifications based on the experience of deployment of earlier ships. Type 744 is designed by the 708th Institute of China State Shipbuilding Corporation, and the 708th Institute is also more commonly known as China Shipbuilding and Oceanic Engineering Design Academy (中国船舶及海洋工程设计研究) nowadays. Construction begun in December 1979 and a total of four was completed, with the last ship entering service in May 1981. The most obvious external visual difference between Type 744 and earlier Type 994 is that the former lacks the mast in the bow. Unlike older Type 985 and Type 994 ships, when Chinese government ordered the maritime navigational responsibility was transferred from PLAN to MOT in the early 1980s, Type 744 buoy tenders were not transferred from military to civilian authorities, and remained in PLAN service. The ship received NATO reporting name as Youdian (延南) class. Specification:
 * Length (m): 72.35
 * Length between perpendiculars (m): 66.6
 * Beam (m): 11.8
 * Depth (m): 6
 * Draft (m): 4
 * Displacement (t): 1750
 * Class notation: ZC
 * Crew: 44
 * Bunks: 52
 * Fuel oil tank (cu m): 161
 * Fresh water tank (cu m): 276
 * Propulsion: Two 8NVD48A-20 diesel engine @ 973 kW each
 * Diesel generator: 72 kW x 4
 * Crane: PBW 12/15 60 kW x 1