OVERVIEW: The Terne III is a Salvo-Launched, unguided Anti-Submarine Warfare rocket system designed for rapid close-range engagement of submerged targets. It launches six 127mm rockets in a pattern to create a high-lethality kill zone around sonar-tracked contacts.

DETAILS: Developed by Kongsberg Våpenfabrikk, the Terne III was a fully integrated ASW system combining ship-mounted sonar, fire control, and a deck-mounted 6-tube rocket launcher. Each rocket carried a high-explosive warhead with hydrostatic fusing and was stabilized by fins for underwater entry accuracy. The system could engage submarines at depths up to 300 meters, with salvos configured to deliver a shaped pattern around the estimated target location. Reloads were performed manually, and the system enabled rapid response against close or fast-approaching contacts.

Compared to older depth charge systems, Terne III offered greater safety, faster reaction time, and increased probability of kill through preprogrammed salvo dispersion. It was specifically tailored to the operational needs of Norway’s Cold War naval doctrine.

It was installed as a fixed, forward-firing 6-tube launcher integrated with the ship’s combat system, guided by sonar tracking. The system was operated from the ship’s CIC, with salvo patterns and fuse depth set prior to launch.

NOTE:
IOC: 1967
Operators: Norway
Platforms: Oslo-class frigates
Conflict used in: No confirmed combat use

SOURCE:
Norwegian Defence Materiel Agency ; Jane’s Naval Weapon Systems ; Kongsberg Defence & Aerospace Archives ; Royal Norwegian Navy Historical Records ; Norwegian Armed Forces Museum