Human torpedo

The concept of a tiny manned submarine carrying a bomb was developed and patented by a British naval officer in 1909, but was never used during the First World War. The Italian Navy experimented with a primitive tiny sub carrying two men and a limpet mine as early as 1918 and this craft did have some success.[1] The first truly practical human torpedo was the Italian Maiale (nicknamed the "pig" because it was difficult to steer) used in the Second World War.[2]

The Maiale was electrically propelled by a 1.6 horsepower (1.2 kW) motor in most of the units manufactured, with a top speed of 3 knots (5.6 km/h) and often required a travel time of up to two hours to its target. Two crewmen in diving suits rode astride, each equipped with an oxygen rebreather apparatus.[1] They steered the craft to the enemy ship. The "pig" could be submerged to 15 metres (49 ft), and hypothetically to 30 metres (98 ft), when necessary.[3] On arrival at the target, the detachable warhead was released for use as a limpet mine. If they were not detected, the operators then rode the mini sub away to safety.

Development began in 1935 but the first 11 were not completed until 1939 by San Bartolomeo Torpedo Workshops in La Spezia, Italy and a larger number followed. The official Italian name for the majority of the craft that were manufactured was Siluro a Lenta Corsa (SLC or "Slow-running torpedo"). Two distinct models were made, Series 100 and then (in 1942) Series 200 with some improvements.[3] At least 50 SLCs were built by September 1943.[3]

In operation, the Maiale torpedo was carried by another vessel (usually a conventional submarine), and launched near the target. Most manned torpedo operations were at night and during the new moon to cut down the risk of being seen. Attacks in 1940 were unsuccessful but in 1941, the Italian navy (Regia Marina) successfully forced the harbour of Alexandria and damaged the two British battleships HMS Queen Elizabeth and HMS Valiant, as well as the tanker Sagona. This feat encouraged the British to develop their own torpedo "chariots". [1]

The last Italian model, the SSB (for Siluro San Bartolomeo, "San Bartolomeo Torpedo") was built with a partly enclosed cockpit, a more powerful motor and larger 300 kg (660 lb) warhead (up from the earlier SLC's 220 and 250 kg (490 and 550 lb) warheads). Three units were made but not operationally used because Italy surrendered in 1943.[4][3]

The first British version of the concept was named the Chariot manned torpedo. Two models were made; Mark I was 20 feet (6.1 m) long while Mark II was 30 feet (9.1 m) long, both suitable for carrying two men. Later versions were larger, starting with the original X-class submarine, a midget submarine, 51 feet (16 m) long, no longer truly a human torpedo but similar in concept. The X-Craft were capable of 6.5 knots (12.0 km/h) on the surface or 5.5 knots (10.2 km/h) submerged. They were designed to be towed to their intended area of operations by a full-size 'mother' submarine.[5]

The German navy also developed a manned torpedo by 1943, the Neger, intended for one man, with a top speed of 4 knots (7.4 km/h) and carrying one torpedo; the frequent technical problems often resulted in the deaths of operators. Roughly 40 of these were made and they did manage to sink a few ships. The later Marder (pine marten in English) was about 27 feet (8.2 m) long and more sophisticated and could dive to depths of 27 metres (89 ft) but with very limited endurance. About 500 were built.[6][7]

CGI image of human torpedo: British Mk 1 "chariot" ridden by two frogmen with UBA rebreathers

A typical manned torpedo has a propeller, hydroplanes, a vertical rudder[8] and a control panel with controls for its front rider. It usually allows for two riders who sit facing forwards. It has navigation aids such as a compass, and nowadays modern aids such as sonar and GPS positioning and modulated ultrasound communications gear. It may have an air (or other breathing gas) supply so its riders do not have to drain their own apparatus while they are riding it. In some the riders' seats are enclosed; in others the seats are open at the sides as in sitting astride a horse. The seat design includes room for the riders' swimfins (if used). There are flotation tanks (typically four: left fore, right fore, left aft, right aft), which can be flooded or blown empty to adjust buoyancy and attitude.

SLC displayed in the "Museo della Scienza e della Tecnica" in Milan

• 1909: The British designer Commander Godfrey Herbert received a patent for a manned torpedo. During World War I, it was rejected by the War Office as impracticable and unsafe.
• 1 November 1918: Two men of the Regia Marina, Raffaele Paolucci and Raffaele Rossetti, in diving suits, rode a primitive manned torpedo (nicknamed Mignatta or "leech") into the Austro-Hungarian Navy base at Pola (Istria), where they sank the Austrian battleship Viribus Unitis and the freighter Wien using limpet mines. They had no breathing sets and they had to keep their heads above water, and thus they were discovered and taken prisoner.[9]
• 1938: In Italy the "1^a Flottiglia Mezzi d'Assalto" (First Fleet Assault Vehicles) was formed as a result of the research and development efforts of two men – Major Teseo Tesei and Major Elios Toschi of the Italian Royal Navy. The pair resurrected the idea of Paolucci and Rossetti.
• 1940: Commander Moccagatta of the Italian Royal Navy reorganised the 1st Fleet Assault Vehicles into the Decima Flottiglia MAS (Tenth Light Flotilla of assault vehicles) or "X-MAS", under the command of Ernesto Forza. It secretly manufactured manned torpedoes and trained war frogmen, called nuotatori (Italian: "swimmers").
• 26 July 1941: An attack on Valletta Harbour ended in disaster for the X MAS and Major Teseo Tesei lost his life.
• 19 December 1941: The Decima Flottiglia MAS attacked the port of Alexandria with three maiali. The battleships HMS Valiant and Queen Elizabeth (and an 8,000-ton tanker) were sunk in shallow water putting them out of action for many months. Luigi Durand de la Penne and five other swimmers were taken prisoner. De la Penne was awarded the Gold Medal of Military Valor after the war.
• October 1942: Two British Chariot manned torpedoes were carried aboard the Shetland bus fishing-boat Arthur to attack the Tirpitz on Operation Title. They were swung overboard once in Norwegian waters but both became detached from their tow-hooks in a gale and the operation was a total failure.[10]
• 8 December 1942. An attack by three manned torpedoes from the Olterra against British naval targets was thwarted in Gibraltar. Three divers were killed by depth charges when the British harbour defence "reacted furiously" to the attack. Among the dead were Lt Licio Visintini, commander of the divers unit on board the Olterra, Petty Officer Giovanni Magro and Sergeant Salvatore Leone, from Taormina, Sicily. Leone's body was never found. Sgt Leone was awarded the Medaglia d'oro al Valor Militare and a memorial was erected in the Community Gardens in Taormina on the 50th anniversary of the attack. The memorial includes a rebuilt maiale and a description of the events, in three languages.
• 1–2 January 1943: British submarines Thunderbolt, Trooper and P311 took part in Operation Principal. P311 was lost en route to La Maddelena but the other two boats had some success at Palermo, launching two and three Chariots respectively. The Ulpio Traiano was sunk and the stern torn off Viminale. However the cost was high with one submarine and one chariot lost and all but two charioteers captured.
• 18 January 1943: Thunderbolt took two chariots to Tripoli for Operation Welcome. This was to prevent blockships being sunk at the harbour mouth, so denying access to the Allies. Again, partial success was achieved. This was the last operation in which chariots were carried in containers on British submarines, although some others followed with the chariots on deck without containers.
• 6 May & 10 June 1943: Italian maiali from the Olterra, now under the command of Lt Ernesto Notari, sank six Allied merchant ships in Gibraltar, for a total of 42,000 tn.
• September 1943: Operation Source was an attempt to destroy warships including the Tirpitz using X-class midget subs. Of the five deployed, only two were successful. Tirpitz was badly damaged, crippled, and out of action until May 1944.[11]
• 2 October 1943: A bigger Italian frogman-carrier, 10 metres (33 ft) long and carrying four frogmen, called Siluro San Bartolomeo, or SSB, was going to attack Gibraltar, but Italy surrendered and the attack was called off.
• 21 June 1944: A British-Italian joint operation was mounted against shipping in La Spezia harbour. The chariots were carried on board an MTB and the cruiser Bolzano was sunk.
• 6 July 1944: A German Neger-type vessel torpedoed the Royal Navy minesweepers HMS Magic and Cato.[12]
• 8 July 1944: A German Neger-type torpedo manned by Lt. Potthast heavily damaged the Polish light cruiser ORP Dragon off the Normandy beaches.
• 20 July 1944: Royal Navy destroyer HMS Isis was mined at anchor in Seine Bay. A German Human Torpedo was believed responsible.[12]
• 27–28 October 1944: The British submarine Trenchant carried two Mk 2 Chariots (nicknamed Tiny and Slasher) to an attack on Phuket harbor in Thailand. See British commando frogmen for more information about this attack. No manned torpedo operations in combat in any war are known with certainty after this date.
• 20 November 1944: The USS Mississinewa is sunk by a Japanese kaiten manned suicide torpedo.
• Immediate post-war period: The British Chariots were used to clear mines and wrecks in harbours.

For other events, see Operations of X Flottiglia MAS and British commando frogmen.

Some nations including Italy have continued to build and deploy manned torpedoes since 1945.

A SLC, or "Maiale", exhibited in the Museo Sacrario delle Bandiere delle Forze Armate, in Rome, Italy

• Original SLCs (Siluri Lenta Corsa or "Maiale") are displayed at the Naval History Museum Venice, Italy.
• There are three chariots on public view in Eden Camp Museum near Malton, North Yorkshire in England:
  • A restored original British Mark II, which was found derelict in a scrapyard in Portsmouth.[20] In this design, the two riders sat back to back.
  • A working chariot that was made in 1992 in Milton Keynes with approximately the outside appearance of a British wartime Mark I, but with differing internal working parts. It has been filmed in action for the television. It has a dummy warhead. [21] It was last used in 2006.
  • A replica Italian maiale made soon after 1945 by the same Italian firm (Caproni) who made the wartime maiali. As at July 2008 this was on loan to the National Maritime Museum Cornwall in Falmouth, Cornwall, until the end of 2008, but as at 16 March 2009 it was back in Eden Camp.
• There is an Italian SSB maiale in the Naval Museum at Groton, Connecticut, United States.

• The movie The Valiant, made in 1962, is about the sinking of HMS Valiant in Alexandria harbour. There is even a 1953 Italian movie (I sette dell'Orsa Maggiore) about the attack, done with some real members of Decima Flottiglia MAS as support actors in the cast.
• The film Above Us the Waves (released in 1955) concentrates on the midget submarine attack on the German battleship Tirpitz. The film has a scene of a fight between British and German frogmen at an anti-submarine net; this never happened in the real attack on Tirpitz.
• The film The Silent Enemy (released in 1958) does not represent real events accurately. In particular, in the real world there was no attack on Olterra, and no underwater hand-to-hand battle between Italian and British frogmen. The breathing sets used by the film actors representing the Italian frogmen seem to be British naval type rebreathers and not authentic Italian rebreathers. The three chariots seen in the movie, representing Italian maiali, were crudely made film props.
• A film The Eagle Has Landed briefly features a German paratroop Officer, a Colonel played by Michael Caine and his men who have been sent to man chariots on the Channel Islands.
• Ian Fleming who wrote the James Bond stories was in Naval Intelligence stationed at Gibraltar in the war, and was likely aware of the Italian operations. The chariot seen in the James Bond film On Her Majesty's Secret Service is a realistic-looking but non-functioning film prop. When seen it is in a kit store. It does not take part in any action; the action happens up a mountain in the Swiss Alps. Underwater vehicles (not chariot-shaped) featured in the James Bond film Thunderball.
• In Metal Gear Solid, Solid Snake uses one to approach Shadow Moses island.
• In Infinity Ward's Call of Duty: Modern Warfare 2, Operators from "Task Force 141" uses two of these to approach one of the four oil rigs. This takes place in the mission: The only easy day, was yesterday.
• In the game Battlestations: Pacific, Kaitens and Kaiten-carrying submarines are player-controllable units.
• In Hidden & Dangerous 2, the only mission set in Norway, entitled "Operation Seawolf: Steam Piping", is based on the failed Operation Title from 31 October 1942 against Tirpitz.

• Kaiten – Manned torpedoes and suicide craft, used by the Imperial Japanese Navy in the final stages of World War II
• Frogman – Tactical scuba diver
• MT explosive motorboat
• Midget submarine – Submarine under 150 tons
• Wet sub – Ambient pressure diver propulsion vehicle
• X class submarine

• Samuel Eliot Morison – History of United States Naval Operations in World War II, Volume XI (1957)

Wikimedia Commons has media related to Human torpedoes.

• The British Chariots, diving gear and personal experiences
• Chariots in armed forces service after 1945
• Vostok: a French 2-man diver-rider that may be a chariot (article in French)
• Underwater Heritage Trust
• Eden Camp Museum
• More images of the restored British Mark II chariot
• Comando Supremo: Italy at War
• British submarines of World War 2
• Chariots, accounts of operations, pictures
• Japanese suicide weapon：Human　torpedo　Kaiten(Japanese)
• HNSA Ship Page: Italian Siluro San Bartolomeo
• Submersible boats
• Eden Camp Museum