HMS ''D7'' was one of eight D-class

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

s built for the

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

during the first decade of the 20th century.

Description

The D-class submarines were designed as improved and enlarged versions of the preceding C class, with

diesel engine The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...

s replacing the dangerous

petrol engine A petrol engine (gasoline engine in American and Canadian English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends ...

s used earlier. ''D3'' and subsequent boats were slightly larger than the earlier boats. They had a length of

overall Overalls or bib-and-brace overalls, also called dungarees in British English, are a type of garment usually used as protective clothing when working. The garments are commonly referred to as a "pair of overalls" by analogy with "pair of trousers ...

, a

beam Beam may refer to: Streams of particles or energy *Light beam, or beam of light, a directional projection of light energy **Laser beam *Radio beam *Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially lo ...

of and a mean draught of . They displaced on the surface and submerged.Harrison, Chapter 4 The D-class submarines had a crew of 25 officers and ratings and were the first to adopt saddle tanks.Gardiner & Gray, p. 87 For surface running, the boats were powered by two diesels, each driving one

propeller shaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power, torque, and rotation, usually used to connect o ...

. When submerged each propeller was driven by a

electric motor An electric motor is a machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a electromagnetic coil, wire winding to gene ...

. They could reach on the surface and underwater. On the surface, the D class had a range of at . The boats were armed with three 18-inch (45 cm)

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, two in the bow and one in the stern. They carried one reload for each tube, a total of six torpedoes.

Construction and career

''D7'' was laid down on 14 February 1910 by

Chatham Dockyard Chatham Dockyard was a Royal Navy Dockyard located on the River Medway in Kent. Established in Chatham, Kent, Chatham in the mid-16th century, the dockyard subsequently expanded into neighbouring Gillingham, Kent, Gillingham; at its most extens ...

, launched 14 January 1911 and was commissioned on 14 December 1911. ''D7'' torpedoed the German submarine on the surface with a single shot from off the North coast of Ireland on 12 September 1917. The torpedo was launched from the stern torpedo tube. Then on 10 February 1918, ''D7'' was mistakenly depth charged by the

destroyer In naval terminology, a destroyer is a fast, maneuverable, long-endurance warship intended to escort larger vessels in a fleet, convoy, or carrier battle group and defend them against a wide range of general threats. They were conceived i ...

but she survived. ''D7'' collided with a

U-boat U-boats are Submarine#Military, naval submarines operated by Germany, including during the World War I, First and Second World Wars. The term is an Anglicization#Loanwords, anglicized form of the German word , a shortening of (), though the G ...

in May 1918. Her periscopes were damaged but she escaped otherwise unscathed. ''D7'' was sold on 19 December 1921 to H. Pounds.

Notes

References

* * * * {{DEFAULTSORT:D07 British D-class submarines 1911 ships Royal Navy ship names