The Yu-7 (; from , meaning ‘torpedo’) is a lightweight

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such ...

developed by the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. It entered service in the 1990s as the principal

anti-submarine An anti-submarine weapon (ASW) is any one of a number of devices that are intended to act against a submarine and its crew, to destroy (sink) the vessel or reduce its capability as a weapon of war. In its simplest sense, an anti-submarine weapon ...

weapon of major

People's Liberation Army Navy The People's Liberation Army Navy, also known as the People's Navy, PLA Navy or simply Chinese Navy, is the naval warfare military branch, branch of the People's Liberation Army, the national military of the People's Republic of China. It i ...

(PLAN) warships. The Yu-7 is a derivative of the

Whitehead Alenia Sistemi Subacquei Leonardo Sistemi di Difesa is an Italian defense company which is part of the Leonardo (company), Leonardo conglomerate. The company specializes in the manufacture of naval weapon systems. The plant based in Livorno came about when the Whitehead To ...

(WASS) A244/S torpedo.

Development

Development of an effective lightweight

(ASW) torpedo for the PLAN began in the 1980s. The program was probably based on 40 A244/S torpedoes purchased for evaluation from Italy in 1987. Additional technology may have been

reverse engineered Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accompl ...

from a

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Mark 46 Mod 2 torpedo recovered from the

South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan island, Taiwan and northwestern Philippines (mainly Luz ...

in 1978 by Chinese fishermen. Development was carried out by the 705th Institute (also known as

Xi'an Xi'an is the list of capitals in China, capital of the Chinese province of Shaanxi. A sub-provincial city on the Guanzhong plain, the city is the third-most populous city in Western China after Chongqing and Chengdu, as well as the most populou ...

Precision Machinery Research Institute, 西安精密机械研究所). The torpedo was initially equipped with electric propulsion, but inadequate performance led to a redesign powered by

Otto fuel II Otto fuel II is a monopropellant mixture of chiefly propylene glycol dinitrate (an ester of nitric acid and propylene glycol, and structurally similar to nitroglycerin) that is used to drive torpedoes and other weapon systems. It was invented by ...

. Testing was carried out at the 750 Testing Range in Kunming up to 1988. One Chinese source alleges that during the intense technology cooperation between the China and the US in the 1980s, a plan was made to license-produce the Mk 46 Mod 2 in China, though it was not completed due to its steep price. Nevertheless, Chinese personnel visited the torpedo-producing facilities at Honeywell, watched the testing of Mk 46 Mod 5 torpedos, and signed a 1985 contract that involves the purchase of 4 completed Mk 46 Mod 2 torpedoes, a maintenance facility, and technical documents by China. The same source claims that China has also studied the

Mark 32 surface vessel torpedo tubes Mark 32 surface vessel torpedo tubes (Mk 32 SVTT) is a torpedo launching system designed for the United States Navy. History The Mark 32 has been the standard anti-submarine torpedo launching system aboard United States Navy surface vessels s ...

on a Pakistani frigate. – 1985 visit relating to Mk 46 is supported by snippets of contemporary Chinese reports.

Description

The Yu-7 has contrarotating propellers. Aboard surface warships, it is fired from Type 7424 tripled 324 mm torpedo launchers; these are copies or derivatives of the WASS B515/ILAS-3.

Deployment

The Yu-7 entered service in the 1990s.

Export variant

The ET52 is an export version of Yu-7. It shares most of the developmental heritage including the A244/S and the Mk 46 Mod 2, but is most notably different in its mechanism of propulsion: a single propeller driven by electric power. Variants that have appeared in text include ET52C and ET52E. Although the electric torpedo has reduced range, it's reportedly only 1/2 to 1/3 the price of a Otto fuel II torpedo.

Yu-11

The Yu-11 () is the successor to the Yu-7. It was first publicly identified in July 2015. The major improvement appears to be the

pump-jet A pump-jet, hydrojet, or water jet is a marine system that produces a jet of water for propulsion. The mechanical arrangement may be a ducted propeller (axial-flow pump), a centrifugal pump, or a mixed flow pump which is a combination of bot ...

propulsor. The Yu-11 torpedo is quieter and may potentially operate at depths greater than 600 metres. The Yu-11 is longer, at three metres, and heavier than the Yu-7. The Yu-11 is likely to become the standard PLAN lightweight torpedo and may have started equipping modern PLAN warships since 2012.

References