HMS ''M2'' was a

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against F ...

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

monitor Monitor or monitor may refer to: Places * Monitor, Alberta * Monitor, Indiana, town in the United States * Monitor, Kentucky * Monitor, Oregon, unincorporated community in the United States * Monitor, Washington * Monitor, Logan County, West ...

completed in 1919, converted in 1927 into a

submarine aircraft carrier A submarine aircraft carrier is a submarine equipped with aircraft for observation or attack missions. These submarines saw their most extensive use during World War II, although their operational significance remained rather small. The most fam ...

. She was wrecked in

Lyme Bay Lyme Bay is an area of the English Channel off the south coast of England. The south western counties of Devon and Dorset front onto the bay. The exact definitions of the bay vary. The eastern boundary is usually taken to be Portland Bill on the ...

Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset (unitary authority), Dors ...

Britain Britain most often refers to: * The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands * Great Britain, the largest island in the United King ...

, on 26 January 1932. She was one of three M-class boats completed.

Design and career

Four M-class submarines replaced the order for the last four K-class submarines, ''K17''-''K21''. Although they were similar in size, the M class was an entirely different design from the K class, although it is possible that some material ordered for the K-boats went into them. In any event, the end of the

First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

meant that only three were completed. ''M2'' was laid down at

Vickers Vickers was a British engineering company that existed from 1828 until 1999. It was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law, and soon became famous for casting church bells. The company went public in 18 ...

shipyard at Barrow in Furness in 1916, and launched in 1918. Like the other members of her class, she was armed with a single fixed 12-inch (305mm) gun as well as

torpedo tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed aboa ...

s. The Mark IX gun was taken from spares held for the ''Formidable''-class

battleship A battleship is a large armored warship with a main battery consisting of large caliber guns. It dominated naval warfare in the late 19th and early 20th centuries. The term ''battleship'' came into use in the late 1880s to describe a type of ...

The M-class submarines were very large for the time at long. They were designed to operate as submarine

monitors Monitor or monitor may refer to: Places * Monitor, Alberta * Monitor, Indiana, town in the United States * Monitor, Kentucky * Monitor, Oregon, unincorporated community in the United States * Monitor, Washington * Monitor, Logan County, West Vir ...

cruiser A cruiser is a type of warship. Modern cruisers are generally the largest ships in a fleet after aircraft carriers and amphibious assault ships, and can usually perform several roles. The term "cruiser", which has been in use for several hu ...

s. They displaced on the surface and when submerged. Two 12-cylinder

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...

s producing drove them on the surface; underwater, they were driven by electric motors producing . After the accidental sinking of in 1925, ''M2'' and her sister were taken out of service and reassigned for experimental use. Her 12-inch gun was removed, replaced by a small aircraft

hangar A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish ...

, the work being completed in 1927. This could carry a small

Parnall Peto The Parnall Peto was a small seaplane designed to the British Air Ministry's specification 16/24 in the early 1920s for use as a submarine-carried reconnaissance aircraft. Design and development Two examples were designed and built by George ...

seaplane A seaplane is a powered fixed-wing aircraft capable of takeoff, taking off and water landing, landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their tec ...

, specially designed for the ''M2'', which, once its wings had been unfolded, could be lowered onto the sea alongside by a

derrick A derrick is a lifting device composed at minimum of one guyed mast, as in a gin pole, which may be articulated over a load by adjusting its guys. Most derricks have at least two components, either a guyed mast or self-supporting tower, and a ...

for take off. On landing, the aircraft was hoisted back onto the deck and replaced into the hangar. In October 1928, a

hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...

aircraft catapult An aircraft catapult is a device used to allow aircraft to take off from a very limited amount of space, such as the deck of a vessel, but can also be installed on land-based runways in rare cases. It is now most commonly used on aircraft carrier ...

was fitted, to enable the seaplane to take off directly from the deck. The submarine was intended to operate ahead of the battle fleet in a

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops (skirmisher ...

role, flying off her unarmed seaplane as a scout. The concept of a submarine cruiser was pursued with , but was not a success and was later abandoned.

Accident

''M2'' left her base at

Portland Portland most commonly refers to: * Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...

on 26 January 1932, for an exercise in

West Bay, Dorset West Bay, originally known as Bridport Harbour, is a small harbour settlement and resort on the English Channel coast in Dorset, England, sited at the mouth of the River Brit approximately south of Bridport. The area is part of the Jurassic C ...

, carrying

serial N255. Her last communication was a radio message at 10:11 to her submarine depot ship, , to announce that she would dive at 10:30. The captain of a passing merchant ship, the

Newcastle Newcastle usually refers to: *Newcastle upon Tyne, a city and metropolitan borough in Tyne and Wear, England *Newcastle-under-Lyme, a town in Staffordshire, England *Newcastle, New South Wales, a metropolitan area in Australia, named after Newcastle ...

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''Tynesider'', mentioned that he had seen a large submarine dive stern first at around 11:15. Unaware of the significance of this, he only reported it in passing once he reached port.Treadwell 1999, pp. 45–46. Her entire crew of 60 was killed in the accident.Treadwell 1999, p. 52. The submarine was found on 3 February, eight days after her loss.Treadwell 1999, pp. 47, 50. Ernest Cox, the salvage expert who had raised the German battleships at Scapa Flow, was hired to salvage the ''M2''. In an operation lasting nearly a year and 1,500 dives, on 8 December 1932, she was lifted to within of the surface before a

gale A gale is a strong wind; the word is typically used as a descriptor in nautical contexts. The U.S. National Weather Service defines a gale as sustained surface winds moving at a speed of between 34 and 47 knots (, or ).hydroplanes Hydroplaning and hydroplane may refer to: * Aquaplaning or hydroplaning, a loss of steering or braking due to water on the road * Hydroplane (boat), a fast motor boat used in racing ** Hydroplane racing, a sport involving racing hydroplanes on lak ...

. High pressure air tanks were used to bring the boat to the surface in an awash condition, but to conserve compressed air compressors were then started to completely clear the ballast tanks of water by blowing air into them. This could take as long as 15 minutes to complete. The normal procedure for launching the aircraft was therefore to hold the boat on the surface using the hydroplanes whilst the hangar door was opened and the aircraft launched. Failure of the stern hydroplanes would have sent the stern down as observed by the merchant officers and water would have eventually entered the hangar.

Aftermath

The submarine currently lies upright on the sea bed at (). Her keel is about below the surface at low tide, and her highest point at the top of the conning tower at around . She is a popular dive for

scuba Scuba may refer to: * Scuba diving ** Scuba set, the equipment used for scuba (Self-Contained Underwater Breathing Apparatus) diving * Scuba, an in-memory database developed by Facebook * Submillimetre Common-User Bolometer Array, either of two in ...

divers. The wreck is designated as a "protected place" under the

Protection of Military Remains Act 1986 Protection is any measure taken to guard a thing against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although th ...

. After the loss of ''M2'', the Royal Navy abandoned submarine-launched aircraft, although other navies experimented with the concept in the inter-war years and with Japan producing some 42 submarine aircraft carriers both before and during the Second World War.Dorr Carpenter, Dorr B. & Polmar, Norman. ''Submarines of the Imperial Japanese Navy'', Conway Maritime Press, 1986.

References

Bibliography

* * Brown, D.K. (2003) ''The Grand Fleet: Warship Design and Development 1906-1922'', London: Caxton Editions, * Treadwell, T.C. (1999) ''Strike from beneath the Sea: a history of aircraft-carrying submarines'', Stroud, UK: Tempus Publishing.
SI 2008/0950
Designation under the Protection of Military Remains Act

External links

Gulls of War, October 1931
article

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