OVERVIEW: The G738 (Type 182) is a towed acoustic decoy system designed to protect surface ships by attracting incoming acoustic-homing torpedoes. It is deployed on a cable behind the ship as a passive lure with no active propulsion.

DETAILS: It is trailed behind the vessel at a safe distance, creating an acoustic signature that mimics or masks the ship’s own noise, thereby misleading torpedoes up to roughly 1.9 km away. The system has seen service on a variety of frigate and destroyer classes beginning in the 1970s, notably on UK Type 21, Type 22, Type 23, and various Indian and Argentinian frigates .

G738 is the NATO or allied designation for China’s Type 182 towed decoy; both names refer to the same system. No unique variants beyond the base model are confirmed, and no propulsion, active jamming, or warhead is present beyond its acoustic lure function.

FUNCTION: The ship deploys the G738 decoy via a towed cable reel; once in the water it passively emits or reflects acoustic noise, presenting an alternative target to incoming active or passive acoustic torpedoes. The decoy remains effective at diverting threats away from the ship’s hull.

NOTE:
IOC: ~1970s (introduction of base G738/Type 182 system)
Operators: United Kingdom, India, Argentina, others using compatible ships
Platforms: Installed on Royal Navy’s Type 21, Type 22, Type 23 frigates, Indian Navy’s Godavari‑class frigates, Argentine Navy’s Almirante Brown–class destroyers

SOURCE:
Jane’s Underwater Defence Systems; Naval Open Source Review: G738 Type 182 specifications; Indian Godavari class system fit reference: https://www.navypedia.org/ships/india/in_es_godavari83.htm ; UK Type 23 fit reference: https://www.piraeuships.eu/2021/06/