Mark 24 Tigerfish

The Mark 24 Tigerfish was a heavyweight acoustic homing torpedo used by the Royal Navy (RN) during the 1980s and 90s. Conceptual development dates to the mid-1950s, and formally started in 1959 with a target introduction date in 1969. A lengthy development process led to a greatly reduced performance requirement, including the removal of anti-surface capabilities. The first prototype "Tiger Fish" examples were delivered in 1967.
The Tigerfish was fitted with both active and passive sonar and could be remotely controlled through a thin wire which connected it to the launching submarine. Wire guidance permits a torpedo to be launched on-first-warning, i.e. when a target is first detected at long range. This gives the torpedo the time needed to close the range while target course and speed are being updated by the submarine's superior sensors and transmitted 'down-the-wire'. The torpedo can also be reassigned to another target or recalled. Typically, wire-guided torpedoes initially run at low speed in order to maximize their range and to minimize their self-generated noise while they close the range, and speed up during the attack phase.
Testing in 1969 revealed many problems, especially...