Yu - 2 torpedo Yu - 2 ( 鱼 - 2 , " Fish - 2 " ) torpedo was a Chinese development of the unguided straight - running Soviet ASuW RAT - 52 torpedo with passive acoustic homing capability added . The historical background of Yu – 2 is identical to that of Yu - 1 torpedo and Yu - 4 torpedo . Contrary to the higher number assigned , Yu - 2 torpedo was the first Chinese domestically produced torpedo entering service , ahead of the Yu - 1 torpedo . Background . In August 1958 , the deputy chief - of - staff of PLA Zhang Aiping and the deputy commander - in - chief of PLAN Luo Shunchu led a military delegation to the Soviet Union and signed a deal with the Soviets to produce three types of torpedoes in China . In comparison with other military programs , each with dozens or even hundreds of Soviet advisers , the total number of Soviet advisers initially sent to China for these torpedo programs was just five . The Soviet Union quickly delivered the samples and technical information for the three types of torpedoes to China with the five advisers as promised . Two Soviet advisers were assigned to assist China to produce the RAT - 52 rocket - powered torpedo at No . 123 Factory , while others were assigned to teach the Chinese about compressed - oxygen powered torpedoes and SAET - 50 acoustic homing torpedoes . In July 1960 the first two samples of Chinese - built rocket propelled torpedoes were completed . The type 920 electrical propulsion system and electronics of the passive acoustic homing torpedo had also been completed , while the basic technologies of compressed oxygen torpedoes were also mastered by the Chinese . The subsequent Sino - Soviet split ended the promising future ; from July 28 to September 1 , 1960 , the Soviet Union had quickly withdrawn all of its advisers from China . Compounding the problem were domestic political turmoils , such as the Great Leap Forward . The 7th Academy consequently ordered the 705th Research Institute to lead a team consisting of No . 724 Factory , Pinyang Machinery Factory ( 平阳机械厂 ) in Houma , Shanxi , and East Wind Instrumentation Factory ( 东风仪表厂 ) in Xi ' an to indigenously manufacture Soviet designed compressed - oxygen powered torpedoes . In 1962 , Field Marshal Nie Rongzhen ordered resources to be concentrated on achieving the goal of fielding “ two boats and a torpedo ” . The two boats were a torpedo boat and a submarine , the torpedo being classed as a heavy torpedo of 533 mm diameter . In July , 1962 , researchers at 705th Institute concluded that compressed - oxygen powered torpedoes were unsafe . After numerous accidental explosions , they were rarely used by either the Soviet or Chinese navy . Chinese researchers recommended steam - power instead , and in the following year PLAN issued an order to first develop a steam - powered torpedo , and then the electrically powered acoustic homing torpedo . Though the Yu - 2 torpedo was not part of this project , due to its earlier commencement , it did benefit from it . One of the two torpedo factories China had set up in the 1950s was assigned as the primary contractor for the Yu - 2 . However , due to the political turmoil in China , the development of Yu - 2 torpedo was subject to several changes . It was ultimately decided to develop two elements in parallel projects . The first project developed the unguided version of the torpedo . The second project developed micro - electronics for the acoustic - homing guidance package . When both were completed the two projects would be merged . Development . China first imported the Soviet RAT - 52 ( RAT : Reaktivnaia Aviacionnaia Torpeda in Russian , meaning rocket airborne torpedo ) rocket propelled ASW torpedo in 1954 and accumulated considerable experience in maintaining and handling the torpedo . With Soviet assistance in July , 1960 , the first two examples of Chinese - built rocket propelled torpedoes were completed . Despite the Soviet withdrawal of technical assistance , a planned torpedo test was carried out in November , 1960 at Lushun . The result , however , was disappointing ; not only that the test failed , one of the two torpedoes immediately sank upon entering water . Since China lacked any elaborate torpedo testing ranges the cause could not be determined . The development of Yu - 2 torpedo was put on hold . In 1964 the development of the Yu - 2 torpedo resumed in China in No . 374 Factory . From July to September , 1969 , a total of 24 torpedoes were test fired with satisfactory results , with speeds reaching 70 knots and ranges in excess of 1 km in water . From March to April , 1970 , another 39 torpedoes were test fired . Like the Yu - 1 torpedo the Chinese micro - electronics industry was not capable of producing the passive acoustic - homing guidance package called for in the original specification . However , also like the Yu - 1 torpedo the unguided version was pressed into service as the Yu - 2 . The acoustic homing version would come years later . Two Yu - 2 torpedoes could be carried by an Ilyushin Il - 28 or a Nanchang Q - 5 . In comparison to the Soviet RAT - 52 torpedo it was based on , the Yu - 2 torpedo had twice the range in water but its warhead was 40 kg lighter . The speed of the Yu - 2 torpedo is 40 / 70kt as opposed to the 58 / 68kt of Soviet RAT - 52 torpedo . Soviet researches have shown that a total of 8 direct hits of the RAT - 52 torpedo would be enough to sink a 50 , 000 ton aircraft carrier . However , due to advances in naval air defenses , it was increasingly difficult for aircraft to come within weapons range of a target . The Chinese solution was to reduce the altitude of the approaching aircraft and attempt to postpone detection long enough to reach weapons range . However , RAT - 52 torpedoes could not be dropped at low altitude . The Chinese solved this problem by incorporating additional control surfaces and modifying the winglets at the tail of the torpedo . Despite being now able to be dropped at very low altitude , incorporating passive acoustic - homing guidance , and having longer range underwater , Yu - 2 torpedoes were obviously not suitable for modern warfare . Chinese research suggested that 8 direct hits on a 50 , 000 ton aircraft carrier was still able to guarantee the sinking , but under the intense air defense and acoustic countermeasures , a minimum of 58 Yu - 2 torpedoes would have to be dropped . This in turn would require that a minimum of 29 aircraft successfully penetrate the fleet air defense . By 1984 all airdropped version of Yu - 2 torpedoes were withdrawn from service . Modification . Production of new Yu - 2 torpedoes ceased a long time ago , however thousands of Yu - 2 torpedoes are undergoing conversion to mines as a coastal defense weapon . Newer electronics have been continuously adopted to upgrade the guidance . In the coastal defense role Yu - 2 torpedoes have also been modified to launch from vehicles and fixed shore batteries and as part of the CAPTOR mine type mine system .