Data[]
| Category. | Data. |
|---|---|
| Type. | Conventional war head Cold War torpedo. |
| Nationality. | Chinese. |
| Made in. | Planned for 1960. Proto-types created in 1961, 1971 and 1987. Formally made in 1987. |
| Retired. | Still in use |
| Designer. | Houma, Shanxi, and East Wind Instrumentation Factory (东风仪表厂), also known as Factory 872) in Xi'an to indigenously manufacture Soviet compressed oxygen powered torpedo (?). |
| Manufacturer. | Houma, Shanxi, and East Wind Instrumentation Factory (东风仪表厂), also known as Factory 872) in Xi'an to indigenously manufacture Soviet compressed oxygen powered torpedo. |
| Variants. | 1. |
| Diameter. | 53.3 cm. |
| Speed. | 30 kt (56 km/h) or 40 kt (75 km) upgraded. |
| Warhead. | 309 kg of N\A. |
| Operational range. | 6 km (original) @ 30 knots (56 km/h), 15 km (upgraded) @ 40 knots (74 km/h). |
| Guidance system. | Acoustic homing: Yu-4A: passive, Yu-4B: active/passive. |
| Launch platform. | Motor torpedo boat and submarine. |
| Weight. | Weight: 1,775 kg (1,628 kg for the training version). |
| Sources. | https://www.wikiwand.com/en/Yu-4_torpedo, http://www.deagel.com/Torpedoes/Yu-4_a002924001.aspx and https://en.wikipedia.org/wiki/Yu-4_torpedo. |
History[]
Overview[]
Yu-4 (鱼-4) torpedo is the Chinese development of the Russian SAET-50 ASuW passive acoustic homing torpedo, and it is the Russian SAET-50 torpedo incorporating active acoustic homing guidance. Yu-4 torpedo is often erroneously claimed by many sources as the Chinese version of the SAET-60 acoustic homing torpedo, but Soviets had not completed the development of SAET-60 and only fielded the weapon in 1961, by then the relationship between former-Soviet Union and China had already worsened and China had not received any technical assistance on SAET-60 torpedo. The background of the development of Yu-4 torpedo is identical to that of Yu-1 torpedo and Yu-2 torpedo.
Early years[]
In August, 1958, the deputy chief-of-staff of PLA Zhang Aiping and the deputy commander-in-chief of PLAN Luo Shunchu (罗舜初) led a military delegation to visit former-Soviet Union 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, the former-Soviet Union did not put too much emphasis on torpedo capability: the total number of Soviet advisors initially sent to China for all of its torpedo programs was only five. The 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.
Everything appeared to be great but the subsequent Sino-Soviet split ended the promising future: from July 28 to September 1, 1960, former-Soviet Union had quickly withdrawn all of its advisers from China. Compounding the problem, other domestic political turmoil such as Great Leap Forward further hindered the Chinese development of torpedoes.
Later upgrades[]
Due to the adoption of newer technologies such as the silver-zinc battery, the performance of Yu-4 torpedo has exceeded the Russian SAET-50 torpedo it is based on, and reached that of SAET-50M: the speed of the Yu-4 torpedo is increased more than 25% to 30 knots (56 km/h), even 1 knot (1.9 km/h) faster than the SAET-50M, and the range is increased 50% to 6 km, equal to that of SAET-50M. For these reasons, the Yu-4 torpedo is considered at least equal or better than Russian SAET-50M torpedo, the successor of SAET-50 torpedo, and even comparable to Russian SAET-60 torpedo in some aspects. However, the 6 km range was considered rather short for modern naval warfare by the Chinese navy, which led to one of the major upgrade resulted in increased range (up to 15 km), and in comparison to Yu-1 torpedo, there were not as many Yu-4 torpedoes entering service like Yu-1 torpedo. Like Yu-1 torpedo, Yu-4 torpedoes in Chinese inventory have been continuously modified, such as incorporating ASW capability, updated electronics and propulsion system, and being converted as part of CAPTOR mine type mine systems.
Modification[]
Due to the adoption of newer technologies such as the silver-zinc battery, the performance of Yu-4 torpedo has exceeded the Russian SAET-50 torpedo it is based on, and reached that of SAET-50M: the speed of the Yu-4 torpedo is increased more than 25% to 30 knots (56 km/h), even 1 knot (1.9 km/h) faster than the SAET-50M, and the range is increased 50% to 6 km, equal to that of SAET-50M. For these reasons, the Yu-4 torpedo is considered at least equal or better than Russian SAET-50M torpedo, the successor of SAET-50 torpedo, and even comparable to Russian SAET-60 torpedo in some aspects. However, the 6 km range was considered rather short for modern naval warfare by the Chinese navy, which led to one of the major upgrade resulted in increased range (up to 15 km), and in comparison to Yu-1 torpedo, there were not as many Yu-4 torpedoes entering service like Yu-1 torpedo. Like Yu-1 torpedo, Yu-4 torpedoes in Chinese inventory have been continuously modified, such as incorporating ASW capability, updated electronics and propulsion system, and being converted as part of CAPTOR mine type mine systems.