SUBROC (SUBmarine ROCket) was a type of submarine launched rocket intended for use as an anti-submarine weapon.
SUBROC could be launched from a 21 inch submarine torpedo tube. After launch, the solid fuel rocket motor fires and SUBROC rises to the surface. The launch angle then changes and SUBROC flies to its destination following a predetermined ballistic trajectory. At a predetermined time in the trajectory, the reentry vehicle (containing the warhead) separates from the solid fuel motor. The warhead (a W55
5 kiloton nuclear weapon) a Nuclear Depth Bomb
drops into the water, sinking rapidly before exploding in proximity to its target. A direct hit is not necessary.
Technically, its tactical use, or raison d'être
was as an urgent-attack long-range weapon that could attack time-urgent submarine targets that could not be attacked with any other weapon without betraying the position of the launching submarine by calling for an air-strike, or where the target was too distant to be attacked quickly with a torpedo launched from the submarine. The tactical rationale for SUBROC was similar to that for ASROC
(see the fuller description on the Ikara
page). An added advantage was that SUBROC's approach to the target was not detectable by the target in time to take evasive action, although the warhead yield would appear to make evasive maneuvers unrealistic. However, SUBROC was less flexible in its use than Ikara or ASROC: since its only payload was a nuclear warhead, it could not be used to provide stand-off fire in a conventional (e.g., non-nuclear) engagement.
The SUBROC used by the US Navy
was the Goodyear UUM-44 SUBROC
. Developed in 1965. SUBROC was never used in combat and all were decommissioned following the end of the Cold War
in 1989. Because the nuclear warhead was an integral part of the weapon, SUBROC could not be exported to other navies, and there is no evidence that any were supplied to other NATO allies under the well-established arrangements for supplying other dual-key nuclear weapons. Towards the end of the 1970s, a planned successor, the UUM-125 Sea Lance
, was frequently delayed due to funding problems and eventually canceled.
Subroc was not strictly an anti-submarine weapon: it was thought that the noisy Alfa-class submarine of the Soviet Union would serve as a beacon as to the location of a Soviet battle group, and a sufficiently large nuclear warhead would destroy not only the submarine, but all accompanying warships as well.
Subroc was featured in the February 1965 issue of National Geographic.