"Details about former Soviet Navy torpedoes are fragmentary but the service has long used 533 mm (21 inch) heavyweight weapons both for submarines and surface vessels, a practice which continued long after the Second World War. These weapons are generally designated Type 53 with a suffix number indicating their date of acceptance into state service, for example, Type 53-38 (the Type 53-56 was produced in China as the YU 1). However electrically powered weapons are designated SAET or Set, with the SAET-50 anti-ship homing torpedo being developed between 1946 and 1950, probably exploiting German technology, while the SET-53 was the first homing anti-submarine torpedo the development of which began in 1950 and was completed in 1958 (produced in China as YU 3). The SET-53 was replaced from 1967 by the SET 65 and it proved the basis for the later Test-71. The SAET-50 was succeeded in 1966 by the SAET-60, the later weapon also being manufactured in China as Yu 4.

In the 1940's and early 1950's these weapons were all for use against surface ships but in the mid-1950's anti-submarine torpedoes were introduced. It would appear that this became the prime role for these when they equipped surface ships, under the Soviet Navy's concept of layered defence, but submarines are likely to retain dual-role weapons."