OVERVIEW: The YT-534-UW1 Valfajr is a heavyweight, acoustic homing torpedo developed by Iran based on the North Korean PT-97W design. It is intended for submarine-launched anti-submarine and anti-surface warfare missions in littoral and regional waters.

DETAILS: The designation "YT-534-UW1" is used by Iranian sources for the system, while "Valfajr" is its public name. The system is believed to be an Iranian-modified derivative of the North Korean PT-97W, itself a development of earlier Soviet torpedoes. Valfajr is wire-guided in its initial phase, followed by passive acoustic terminal homing. It reportedly carries a large high-explosive warhead and is capable of operating at moderate depths and speeds, though exact performance characteristics remain classified.

TYPE: Heavyweight Torpedo

FUNCTION: After launch from a submerged platform, the Valfajr is guided by wire during the initial phase and uses onboard passive sonar to acquire and engage its target. It is designed to engage enemy submarines and surface ships with a high-damage warhead.

NOTE:
IOC: Unknown (PT-97W), 2015 (Valfajr)
Manufacturer: Iran (Ministry of Defense and Armed Forces Logistics)
Operators: Iran
Platforms: Confirmed on Iranian Kilo-class (Tareq-class) submarines
Conflict used in: none

SOURCE:
Iranian Ministry of Defence: https://www.mod.ir ; Iranian Armed Forces Broadcasts (IRINN): https://www.irinn.ir ; IISS The Military Balance ; GlobalSecurity.org: https://www.globalsecurity.org/military/world/iran/valfajr.htm ; Wikipedia: https://en.wikipedia.org/wiki/Valfajr_torpedo