Type 073 medium landing ship The Type 073 landing ship medium is a class of landing ship medium ( LSM ) of the People ' s Liberation Army Navy ( PLAN ) consisted of several models . One of this class was exported to Sri Lanka . Type 073I landing ship medium . Requirement of Type 073 medium landing ship was finalized in May 1965 , and design work by Shanghai - based 708th Research Institute completed just 4 months later in September 1965 . Preparation to build this class was completed in October 1966 , and construction begun a month later in November 1966 . Due to political turmoil in China at the time , namely , Cultural Revolution , it was not until almost three years later in August 1969 when the ship was launched . From November 1969 thru December 1969 , extensive trials were conducted and the ship was handed over to PLAN in December 1969 for further tests . In 1970 more tests were conducted with more than logged , and the longest trip was from Chongqing to Dalian . However , trials revealed that the vibration was too great at high speed , and Type 073 LSM did not enter production . Redesign work designated as Type 073II immediately started after the trials of the first unit ended , and the first unit entered PLAN service with pennant number 904 was subsequently designated as Type 073I , and was later ordered to be converted to Type 073II standard . Due to the political turmoil at the time , conversion was not completed until 1975 . Type 073II landing ship medium . Shortcomings of Type 073I exposed in trials caused a crush program to rework and redesign at Dalian Shipyard , but due to political turmoil in China at the time , it was not sufficient enough to correct the problem completely . Shipyard # 9308 in Anhui petitioned the 6th Machinery Industrial Ministry and Anhui provincial Defense Industrial Office to construct Type 73II LSM in 1975 , which was approved in April 1976 , with orders for 3 ships . Construction of the first Type 073II LSM at Shipyard # 9308 begun five months later in September 1976 , and it was launched in June 1978 . From 1978 to 1979 , extensive trials were conducted and the ship was handed over to PLAN in early 1980 , with pennant number East Transport 757 ( East Transport = Dong Yun 东运 in Chinese ) , meaning Transport 757 of East Sea Fleet of PLAN . This unit was later reassigned as # 937 . The primary difference between Type 073I and Type 073II is in the engine . Additional balance weight was added to the diesel engine which solved the vibration problem , but the reliability issue of the engine remain unsolved , and as a result , Type 073II did not enter mass production , just like its predecessor Type 073I . Type 073IIY landing ship medium . As the mass production plan for Type 073II was cancelled due to reliability problem of its engine , Shipyard # 9308 begun to modify the remaining two units that were already being built , which was successfully completed in September 1985 . The resulting type is Type 073IIY , with Y for Yun ( 运 ) , meaning transport in Chinese . Type 073I , Type 073II , and Type 073IIY all received the NATO reporting name Yudao class . A total of two units of Type 073IIY were completed , with pennant # Dongyun 800 ( later renamed as # 938 Lüliang Mountains ) and Dongyun 801 . The primary difference between Type 073II and Type 073 IIY includes more than 100 upgrades in addition to engine improvement . Type 073III landing ship medium . The reliability problem of the engine of Type 073 series was not completely solved until the appearance of Type 073III LSM , with NATO reporting name Yudeng class . The D - 39 engine that is reliable only at slower speed was replaced by a new engine that is reliable at all speeds , and displacement is also increased . Only one unit entered service , with pennant # 990 in 1991 . After the completion of the first unit ( pennant # 990 ) , it takes a decade for more units to follow , and 10 more entered service between 2001 through 2002 . These later units are lightly larger in displacement at 2000 tons , and more advanced equipment , mainly in electronics and on board machinery . This latest batch is referred by some internet sources as Type 073 IV is known as Yunshu , but such claim has yet to be verified by official / governmental sources .