British 21 inch torpedo
Encyclopedia
There have been several British 21-inch (53 cm) diameter torpedoes used by the Royal Navy
since their first development just before the First World War.
They were the largest size of torpedo in common use in the RN. They were used by surface ships and submarines rather than aircraft which used smaller 18 inch torpedoes.
The Mark II*, an improved Mark II was used by battleships and battlecruisers. A wet heater design, it could run for 4.1 km (4,483.8 yd) at 45 knots (88.2 km/h)
.
and B
destroyers and, with modification, by the Kent-class heavy cruisers.
period.
The power came from the use of oxygen enriched air, though torpedo stocks were converted to run on normal air at the start of the Second World War.
Designed around 1925 as the first British burner-cycle design, it was used from 1927 for submarines of O class onwards and motor torpedo boat
s.
The improved V** version used a 805 lb (365 kg) Torpex
warhead and was capable of 45 knots.
It was still in use in the 1980s, three Mark VIII** being used to sink the Argentine cruiser during the 1982 Falklands War
.
, giving it a speed of 28 knots (54.9 km/h) for 5 km (5,468.1 yd).
There were accidents during testing caused by the unstable nature of HTP. One such engine explosion, after loading on the submarine HMS Sidon
, caused enough damage to have the submarine taken permanently out of service.
Mark 12 torpedoes were out of service in 1959 and the programme was cancelled.
s intended to use them (Rothesay
and Whitby
classes) never being fitted with torpedo tubes or having them removed.
It was replaced in the submarine service in the 1980s by Tigerfish
.
anti-submarine aircraft. It was cancelled after protracted work but the seeker development was used in Tigerfish.
There were several models of Tigerfish due to the modifications made to tackle deficiencies.
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
since their first development just before the First World War.
They were the largest size of torpedo in common use in the RN. They were used by surface ships and submarines rather than aircraft which used smaller 18 inch torpedoes.
21 inch Mark I
The first British 21 inch torpedo came in two lengths "Short" at 17 ft 10.5 in (5.45 m), and "Long" at 23 ft 1.25 in (7.04 m). The explosive charge was 200 lb of gun cotton increased later to 225 lb.21 inch Mark II
The Mark II, chiefly used by destroyers, entered service in 1914. Apart from some older British ships, it was used with the old US (destroyers for bases agreement) destroyers provided to the UK during the early part of the Second World War. The running speed was reduced from 45 knots (over 3,000 yards) for better reliability.The Mark II*, an improved Mark II was used by battleships and battlecruisers. A wet heater design, it could run for 4.1 km (4,483.8 yd) at 45 knots (88.2 km/h)
21 inch Mark IV
From 1912, used by destroyers and other surface ships and was an important weapon in the first World War. In the Second World War they were carried on HMS HoodHMS Hood
Three ships of the Royal Navy have been named HMS Hood after several members of the Hood family, who were notable Navy officers: was a 91-gun second-rate ship of the line, originally laid down as HMS Edgar, but renamed in 1848 and launched in 1859. She was used for harbour service from 1872 and was...
.
21 inch Mark V
The Mark V was used by the AA class destroyer
The A class was a flotilla of eight destroyers built for the Royal Navy as part of the 1927 naval programme. A ninth ship, Codrington, was built to an enlarged design to act as the flotilla leader...
and B
B class destroyer
The B class was a class of nine destroyers of the British Royal Navy, ordered as part of the 1928 Naval Estimates, launched in 1930 and that commissioned in 1931. The class was similar to the preceding A class, with minor modifications...
destroyers and, with modification, by the Kent-class heavy cruisers.
21 inch Mark VII
The Mark VII was issued for use on the British heavy cruisers; i.e. cruisers with 8-inch guns. Designed in the mid 1920s the s were built at the same time in the post Washington Naval TreatyWashington Naval Treaty
The Washington Naval Treaty, also known as the Five-Power Treaty, was an attempt to cap and limit, and "prevent 'further' costly escalation" of the naval arms race that had begun after World War I between various International powers, each of which had significant naval fleets. The treaty was...
period.
The power came from the use of oxygen enriched air, though torpedo stocks were converted to run on normal air at the start of the Second World War.
21 inch Mark VIII
- Weight: 3,452 lb (1,566 kg)
- Length: 259 inches (21.6 ft) (6.58 m)
- Explosive Charge: 805 lb (365 kg) TorpexTorpexTorpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...
- Range and Speed: 5,000 yards (4,570 m) / 45.5 knots
Designed around 1925 as the first British burner-cycle design, it was used from 1927 for submarines of O class onwards and motor torpedo boat
Motor Torpedo Boat
Motor Torpedo Boat was the name given to fast torpedo boats by the Royal Navy, and the Royal Canadian Navy.The capitalised term is generally used for the Royal Navy boats and abbreviated to "MTB"...
s.
The improved V** version used a 805 lb (365 kg) Torpex
Torpex
Torpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...
warhead and was capable of 45 knots.
It was still in use in the 1980s, three Mark VIII** being used to sink the Argentine cruiser during the 1982 Falklands War
Falklands War
The Falklands War , also called the Falklands Conflict or Falklands Crisis, was fought in 1982 between Argentina and the United Kingdom over the disputed Falkland Islands and South Georgia and the South Sandwich Islands...
.
21 inch Mark XI
Electric battery powered torpedo with a 322 kg (709.9 lb) TNT warhead. Entering service during the Second World War it was used by destroyers.21 inch Mark 12
Codenamed first "Ferry" then "Fancy", the Mark 12 never reached production. From 1952, a warhead of 340 kg (749.6 lb) Torpex. Powered by high test peroxideHigh test peroxide
High-test peroxide or HTP is a high -concentration solution of hydrogen peroxide, with the remainder predominantly made up of water. In contact with a catalyst, it decomposes into a high-temperature mixture of steam and oxygen, with no remaining liquid water...
, giving it a speed of 28 knots (54.9 km/h) for 5 km (5,468.1 yd).
There were accidents during testing caused by the unstable nature of HTP. One such engine explosion, after loading on the submarine HMS Sidon
HMS Sidon (P259)
HMS Sidon was a submarine of the Royal Navy, launched in September 1944, one of the third group of S-class submarines built by Cammell Laird & Co Limited, Birkenhead...
, caused enough damage to have the submarine taken permanently out of service.
Mark 12 torpedoes were out of service in 1959 and the programme was cancelled.
21 inch Mark 20 Bidder
Developed under the codename "Bidder", the Mark 20 was a passive-seeker battery-powered torpedo for use by surface ships (the Mark 20E - for "Escort") and submarines (Mark 20S). The E variant was not long in service due to problems with its programming. This led to several of frigateFrigate
A frigate is any of several types of warship, the term having been used for ships of various sizes and roles over the last few centuries.In the 17th century, the term was used for any warship built for speed and maneuverability, the description often used being "frigate-built"...
s intended to use them (Rothesay
Rothesay class frigate
The Rothesay class, or Type 12M frigates were a class of frigates serving with the Royal Navy, South African Navy and the New Zealand Navy....
and Whitby
Whitby class frigate
The Type 12 frigates of the Whitby class were a six-ship class of anti-submarine warfare frigates of the Royal Navy that entered service late in the 1950s. They were designed as first rate ocean-going convoy escorts in light of experience gained during World War II...
classes) never being fitted with torpedo tubes or having them removed.
It was replaced in the submarine service in the 1980s by Tigerfish
Mark 24 Tigerfish
The Mk 24 Tigerfish torpedo was a heavyweight acoustic homing torpedo used by the Royal Navy for several years. The early Mod0 and Mod1 variants were unreliable and unsuccessful, and were issued to the RN even though they failed Fleet Weapon Acceptance...
.
21 inch Mark 21 Pentane
A project for an autonomous active/passive sonar torpedo to be carried by the Short SturgeonShort Sturgeon
The Short Sturgeon was a British aircraft originally designed in the Second World War as a high-performance torpedo bomber. With the end of the war in the Pacific it was no longer needed as such. Through shifting priorities postwar, the Sturgeon was redesigned first into a target tug and then later...
anti-submarine aircraft. It was cancelled after protracted work but the seeker development was used in Tigerfish.
21 inch Mark 22
A wireguided version of the Mark 20 produced by Vickers Shipbuilding and Engineering (VSEL) as a private venture21 inch Mark 23 Grog
A wireguided version of the Mark 20. Entered service in the 1971 although already obsolescent, serving only as an interim before Tigerfish entered service.Mark 24 Tigerfish
The first Tigerfish (Mod 0) entered service in 1980. Tigerfish was removed from service in 2004.There were several models of Tigerfish due to the modifications made to tackle deficiencies.
- Mark 24 Mod 0 Tigerfish
- Mark 24 Mod 1 Tigerfish
- Mark 24(N) Tigerfish
- Mark 24 Mod 2 Tigerfish