Terne is a Norwegian anti-submarine weapon system, which uses rocket-thrown depth charges. It was developed by the Norwegian Defence Research Establishment (FFI) in cooperation with the U.S. Navy in the late 1940s-early 1960s. The Terne development project consisted of three phases:

Terne III Mk8
Terne III Mk.8 ASW system opening its clam gate
Type	Anti-submarine weapon
Service history
In service	1964
Production history
Manufacturer	Kongsberg Defence & Aerospace and A/S Raufoss
Produced	1950 (Terne I)
Specifications
Mass	135 kg
Length	1.95 m
Diameter	0.21 m
Wingspan	0.24 m
Warhead	50 kg
Detonation mechanism	Delay Fuse
Engine	Solid-fueled Rocket; 52 kN (11700 lb)
Operational range	425-1600 m
Guidance system	Unguided rocket + depth charge
Launch platform	Land and Naval ships

Terne I  : Development of a rocketborn depth charge.

Terne II: Development and construction of a landbased ASW for naval defense.

Terne III: Development and construction of a shipborne ASW.

A Terne III weapon system consists of a search & track sonar, a fire-control system and the rocket launchers, which can store six salvos of six rockets each. The rocket itself, is a depth charge with multiple fusing modes (preset time after water entry, proximity, or contact), which is propelled through the air by a solid-fueled rocket motor. When the sonar detects a target, the fire-control system can fire a rocket salvo to place a string of depth charges 18 m (20 yd) apart, perpendicular to the target's course.