Mark 24 Tigerfish
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The Mk 24 Tigerfish torpedo is a heavy Acoustic homing torpedo used by the Royal Navy for several years. It has been replaced in service by the much more capable Spearfish torpedo. It is fitted with both active and passive sonar and can be remotely controlled through a thin wire which connects 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 permits the torpedo the time needed to close the range while target course and speed is being updated by the submarine's superior sensors and transmitted 'down-the-wire'; and also permits the torpedo to be re-assigned to another target or recalled. Typically, wire-guided torpedoes run at high speed to close the range (the approach speed) and slow down to minimise self-generated noise interference with on-board sensors during the attack phase (the attack speed).
Early models suffered from poor reliability - only 40% of the Mod 0 ASW model performed as designed. The torpedo depended in large part on the remote control system but the weapon tended to dip during launch, severing the control wire. The Mod 0 failed its initial fleet acceptance trials in 1979 but was nevertheless issued to the fleet in 1980. The Mod 1 DP (dual purpose) anti-submarine and anti-ship model also experienced problems, though a redesigned version (Mod 2) passed sea trials in 1978 and was issued the following year. When HMS Conqueror sank the ARA General Belgrano during the 1982 Falklands war she used more than 50 year old, but far more reliable, Mark 8 torpedoes rather than the Tigerfish which she also carried. In a test carried out after the war two of five Mod 1 Tigerfish fired at a target hulk failed to function at all and the remaining three failed to hit the target.
Originating from the Mackle wire-guidance study dated 1952[1][2] and the later Ongar project[3] for a wire-guided torpedo to counter deep-diving Soviet SSNs, the original requirement for a crush depth of 1'000 ft (301 m) was overtaken by rapid advances in SSN deep-diving performance, and the requirement was progressively increased to 1,600 ft (488 m) and then 2,000 ft (602 m). Tigerfish never met these requirements and the best that could be achieved was 1,150 ft (350 m) and later 1,450 ft (442 m).[4] The structure was incapable of further crush-depth development, and a measure of the Royal Navy's desperation for a reliable means of dealing with fast, deep-diving time-urgent targets at long-range resulted in a project to arm Tigerfish with a nuclear warhead to offset its poor depth performance and increase kill probability close to 90%.[5] Various other measures were proposed in mid-1969, including purchase of the U.S. Mark 45 Captor nuclear torpedo, or the U.S. Mark 48 Mod-1, or Subroc from the United States, or at the initiative of Flag Officer Submarines (FOSM), fitting a nuclear warhead to the unguided, shallow-running and short-ranged, but reliable 21" Mark 8 torpedo.[6] Flag Officer Submarines minuted that the proposal to arm the Mark 8 with the WE.177A warhead would, despite the torpedo's performance shortcomings, be "much superior to any present British submarine weapon ..." The Plessey and later Marconi programme of the early 1980s finally produced the Mod 2 with reliability improved to 80%, which the Royal Navy accepted as the best that could be achieved with a basic design that was incapable of further development. By 1987 all 600 Tigerfish were modified to the Mod 2 standard.
Versions were:
- Mark 24-Mod-0 for ASW use. Dive depth 1,150 ft (350 m).
- Mark 24-Mod-1 (or Mark 24 DP) for ASW and ASV use. Dive depth 1,450 ft (442 m).
- Mark 24-Mod-1-N for ASW and ASV use. Dive depth 1,450 ft (442 m). The nuclear version.
- Mark 24-Mod-2 for ASW and ASV use. Dive depth 1,450 ft (442 m). The Marconi upgrade.[7]
In 1990 Cardoen of Chile was granted a license to manufacture Tigerfish for the Chilean, Brazilian and Venezuelan navies.
The Royal Navy retired the last of the Tigerfish torpedoes from service in February 2004.
[edit] General characteristics
- Speed: 64 km/h (35 knots)
- Range: 39 km (22 nautical miles) at low speed, 13 km (7 nautical miles) at high speed
- Length: 6.5 m (21.2 ft)
- Diameter: 533 mm (21 in)
- Weight: 1550 kg (3414 lb)
- Warhead: 134 to 340 kg (295 to 750 lb) Torpex
- Power plant: Electrical
- Fuel: chloride silver-zinc oxide batteries
- Guidance System: Wire guided with active terminal homing sonar
- First deployed: late 1970s
