OVERVIEW: The Yu-1 is an unguided, straight-running heavyweight torpedo developed by China and entered service in 1973. It was designed for submarine-launched attacks against surface ships using passive targeting.

DETAILS: The designation "Yu" (鱼) means "fish" in Chinese and is the standard nomenclature for Chinese torpedoes. The Yu-1 is a domestic Chinese copy of the Soviet Type 53-56 torpedo, reverse-engineered in the 1960s and finalized by 1971. It is powered by a steam turbine using kerosene and high-pressure air, with no onboard guidance system beyond its preset gyroscopic course. The torpedo was equipped with a high-explosive warhead and was intended for use against surface vessels in pre-identified engagement scenarios where targeting data was known before launch.

TYPE: Straight-Running Heavyweight Torpedo

FUNCTION: The Yu-1 operates by running along a preset course determined before launch, relying on gyroscopic stabilization. It is effective only against targets that remain on or near their expected course and position, making it suitable for pre-planned anti-ship attacks.

NOTE:
IOC: 1973 (Yu-1)
Manufacturer: China (Norinco/CSIC)
Operators: China
Platforms: Type 033-035 submarine

SOURCE:
China Defense White Paper: https://english.www.gov.cn/archive/white_paper ; Jane’s Naval Weapon Systems ; China Defense Today: https://www.sinodefence.com/navy/weapon/yu1.asp ; Wikipedia: https://en.wikipedia.org/wiki/Yu-1_torpedo