Yu-1 torpedo

Yu-1 Torpedo
A Yu-1 torpedo on display at the Beijing Military Museum
Type	Steam-powered torpedo
Place of origin	China
Service history
In service	1971-
Used by	China, Albania, Bangladesh, Romania, Pakistan, Tanzania
Production history
Designer	Originally Soviet Union modified by Chinese
Designed	late 1950s – early 1960s
Manufacturer	China, Romania
Produced	1971 -
Specifications
Weight	2,000 kg
Length	7.8 m
Diameter	533 mm
Warhead weight	400 kg
Engine	Steam
Operational range	3.5 km at 50 knots 9 km at 39 knots
Speed	39 to 50 knots
Guidance system	Straight running gyroscopic, later upgraded to passive acoustic homing

The Yu-1 (鱼-1) torpedo was the first Chinese-built steam-powered torpedo; it was a development of the unguided straight-running Soviet ASuW Type 53 torpedo. It was type classified in September 1971. The Yu-1 was actually the second domestically produced torpedo to enter Chinese service; the first was the Yu-2 torpedo. During the 1980s a version was developed with passive acoustic homing designated the Yu-1A.

In August 1958, the deputy chief-of-staff of People's Liberation Army (PLA) Zhang Aiping and the deputy commander-in-chief of People's Liberation Army Navy (PLAN) Luo Shunchu (罗舜初) led a military delegation to visit the Soviet Union and signed a deal with Soviets to produce three types of Soviet torpedoes in China. In comparison with other military programs each with dozens or even hundreds of Soviet advisors, however, Soviet Union did not put too much emphasis on the torpedo capability: the total number of Soviet advisors initially sent to China for all of its torpedo programs was only five. Soviet Union quickly delivered the samples and technical information of the three types of torpedoes to China with the five advisors to China as promised. Two Soviet advisors were assigned to assist China to produce the RAT-52 rocket-powered torpedo at No. 123 Factory, while others were assigned to teach China about compressed oxygen powered torpedo and SAET-50 acoustic homing torpedoes. In July 1960, the first two samples of Chinese-built rocket propelled torpedoes were completed. Type 920 electrical propulsion system and electronics of the electrically powered passive acoustic homing torpedo had also been completed, while the basic technologies of compressed oxygen torpedoes were also mastered by China.

The subsequent Sino-Soviet split ended the development relationship, and from July 28 to September 1, 1960, the Soviet Union withdrew its advisers. Compounding the problem, other domestic political turmoil such as Great Leap Forward further hindered the Chinese development of torpedoes. The 7th Academy consequently ordered the 705th Research Institute to lead a team consisted 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 compressed oxygen powered torpedo. In 1962, Field Marshal Nie Rongzhen ordered all resources to be concentrated on achieving the goal of fielding “two boats and a torpedo” (Two boats: torpedo boat and submarine, torpedo: heavy torpedo of 533 mm diameter).