|Type.||Conventional Cold War Torpedo.|
|Retired.||1993 in Norway (a coastal fort torpedo battery).|
|Variants.||3 in the UK, plus S. Africa's Steel Fish!\Staal Vis!.|
|Warhead.||750 lb (340 kg) TNT.|
|Operational range.||5,000 yards (4,570 m).|
|Launch platform.||Submarines, escorts frigates, ASW frigates, coastal forts and ASW aircraft.|
|Weight.||N\A, but probably akin to those of comparable role, configuration and era.|
21 inch Mark VIII variants-
- Mark VIII
- Entered Service: 1927
- Weight: 3,452 lb (1,566 kg)
- Length: 259 inches (21.6 ft) (6.58 m)
- Explosive Charge: 750 lb (340 kg) TNT
- Range & Speed: 5,000 yards (4,570 m) / 40 knots
- Early Mark VIII**
- Range & Speed: 5,000 yards (4,570 m) / 45.6 knots
- Explosive Charge: 722 lb (327 kg) Torpex
- Late Mark VIII**
- Range & Speed: 7,000 yards (6,400 m) / 41 knots
- Explosive Charge: 805 lb (365 kg) Torpex
The Mark VIII was designed around 1925 and was the first British burner-cycle design torpedo. It was used from 1927 on submarines of the O class onwards and motor torpedo boats. The principal World War II version was the improved Mark VIII**, 3,732 being fired by September 1944 (56.4% of the total number). The torpedo was still in service with the Royal Navy as late as 1983, and with the Royal Norwegian Navy (Coastal Artillery: Kaholmen torpedo battery at Oscarsborg Fortress) until 1993.
On 9 February 1945 the Royal Navy submarine HMS Venturer sank the German submarine U-864 with four Mark VIII** torpedoes. This is the only intentional wartime sinking of one submarine by another while both were submerged.
On 2 May 1982 the Royal Navy submarine HMS Conqueror sank the Argentine cruiser ARA General Belgrano with three Mark VIII** torpedoes during the Falklands War. This is the only sinking of a surface ship by a nuclear-powered submarine in wartime (and only the second sinking of a surface ship by any submarine since the end of World War II).