The R-class submarines were a class of 12 small British

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 diesel

Diesel engine

A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...

-electric submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

s built for the Royal Navy

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...

 during World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, and were forerunners of the modern hunter-killer submarines, in that they were designed specifically to attack and sink enemy submarines, their battery capacity and hull shape being optimized for underwater performance.

With a submerged speed of 14 kn (7.6 m/s), the class set an underwater speed record not broken until the experimental Japanese Submarine Number 71 of 1938, which was capable of more than 21 kn (11.4 m/s) submerged.

Description

Ordered in December 1917, the R-class were designed to be faster underwater than on the surface, achieving a submerged speed of 14 kn (7.6 m/s) versus a surfaced speed of 9 knots (17.6 km/h). They were well-streamlined, having no external ballast tanks, casing, or deck

Deck (ship)

A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary deck is the horizontal structure which forms the 'roof' for the hull, which both strengthens the hull and serves as the primary working surface...

 gun, and a streamlined

Streamliner

A streamliner is a vehicle incorporating streamlining in a shape providing reduced air resistance. The term is applied to high-speed railway trainsets of the 1930s to 1950s, and to their successor "bullet trains". Less commonly, the term is applied to fully faired recumbent bicycles...

 spindle

Spindle (textiles)

A spindle is a wooden spike used for spinning wool, flax, hemp, cotton, and other fibres into thread. It is commonly weighted at either the bottom middle or top, most commonly by a circular or spherical object called a whorl, and may also have a hook, groove or notch, though spindles without...

-shaped hull

Hull (watercraft)

A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...

 of circular cross-section (not reproduced until the Los Angeles-class

Los Angeles class submarine

The Los Angeles class, sometimes called the LA class or the 688 class, is a class of nuclear-powered fast attack submarines that forms the backbone of the United States submarine fleet. With 43 submarines on active duty and 19 retired, the Los Angeles class is the most numerous nuclear powered...

) which tapered sharply towards the stern and allowed only for a single screw

Propeller

A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...

. The bulbous bow contained five sensitive hydrophones

Sonar

Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...

 and the lightened conning tower

Conning tower

A conning tower is a raised platform on a ship or submarine, often armored, from which an officer can con the vessel; i.e., give directions to the helmsman. It is usually located as high on the ship as practical, to give the conning team good visibility....

 was also well-streamlined.

Thirty-five percent of the space inside the pressure hull was occupied by machinery. A single 8-cylinder 480 hp Diesel engine was installed for surface propulsion, while high underwater speed was given by two large electric motors arranged one behind the other to drive the single propeller shaft, and powered by a 200-cell battery of the same type fitted to J-class

British J class submarine

The J class of submarines was a seven submarine class developed by the Royal Navy prior to the First World War in response to claims that Germany was developing submarines that were fast enough to operate alongside surface fleets...

 submarines. The large battery was, however, sufficient for only about an hour at full power. In addition, the engine took a full day to charge the batteries, using half its power. Charging was therefore undertaken in harbour, using a supply of electricity from the shore or from special battery charging vessels.

Despite being designed for maximum underwater performance, the R-class submarines were extremely difficult to control submerged, especially at high speeds. Surfaced, they had poor seakeeping and were slow. Minor modifications were made to R4

HMS R4

HMS R4 was a British R class submarine built at Chatham Dockyard. She was laid down on 4 March 1917 and launched on 8 June 1918. R4 was commissioned on the 23 August 1919. She came too late to see any combat in World War I, like most of the other R class submarines...

, the only submarine of the class to survive into the 1930s, which made it more manageable on the surface, but reduced its submerged speed to a maximum 13 kn (7.1 m/s).

Armament

The R-class were the first Royal Navy submarines to be fitted with six bow

Bow (ship)

The bow is a nautical term that refers to the forward part of the hull of a ship or boat, the point that is most forward when the vessel is underway. Both of the adjectives fore and forward mean towards the bow...

 torpedo

Torpedo

The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...

 tubes, number of torpedoes being considered more important than range or size of warhead carried when attacking U-boats. The torpedo tubes were originally the smaller 18 inches (457.2 mm) but later changed to 21 inches (533.4 mm). As designed, one spare torpedo was allowed for, but in operation six reloads were carried in place of the senior Ratings' accommodation. It was originally intended to fit a 4 inch gun on the foredeck, but this was dropped due to the adverse effect it would have had on submerged speed.

Construction

R-1 through R-4 were ordered from Chatham

Chatham Dockyard

Chatham Dockyard, located on the River Medway and of which two-thirds is in Gillingham and one third in Chatham, Kent, England, came into existence at the time when, following the Reformation, relations with the Catholic countries of Europe had worsened, leading to a requirement for additional...

, R-5 and R-6 from Devonport

HMNB Devonport

Her Majesty's Naval Base Devonport , is one of three operating bases in the United Kingdom for the Royal Navy . HMNB Devonport is located in Devonport, in the west of the city of Plymouth in Devon, England...

 (later changed to Pembroke

Pembroke Dock

Pembroke Dock is a town in Pembrokeshire, south-west Wales, lying north of Pembroke on the River Cleddau. Originally a small fishing village known as Paterchurch, the town was greatly expanded from 1814 onwards following the construction of a Royal Naval Dockyard...

), R-7 and R-8 from Vickers

Vickers

Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

, R-9 and R-10 from Armstrong

Armstrong Whitworth

Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. Headquartered in Elswick, Newcastle upon Tyne, Armstrong Whitworth engaged in the construction of armaments, ships, locomotives, automobiles, and aircraft.-History:In 1847,...

, and R-11 and R-12 from Cammell Laird

Cammell Laird

Cammell Laird, one of the most famous names in British shipbuilding during the nineteenth and twentieth centuries, came about following the merger of Laird, Son & Co. of Birkenhead and Johnson Cammell & Co. of Sheffield at the turn of the twentieth century.- Founding of the business :The Company...

. In August 1919, with World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 over, R-5 and R-6 were cancelled, the rest being completed. To save time, they used H-class

British H class submarine

The British H class submarines were Holland 602 type submarines used by the Royal Navy. The submarines constructed for the British Royal Navy between 1915 and 1919 were designed and built in response to German boats which mined British waters and sank coastal shipping with ease due to their small...

 components.

Service

Operating out of Killybegs

Killybegs

Killybegs is the largest fishing port in County Donegal and in Ireland. It is located on the south coast of the county, north of Donegal Bay, near Donegal Town. The town is situated at the head of a scenic harbour and at the base of a vast mountainous tract extending northward...

, Donegal

County Donegal

County Donegal is a county in Ireland. It is part of the Border Region and is also located in the province of Ulster. It is named after the town of Donegal. Donegal County Council is the local authority for the county...

, one of the class reportedly tracked and fired on a U-Boat

U-boat

U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

 in October 1918, firing a full salvo of six torpedoes of which only one hit but did not detonate.

All but R-4 and R-10 were sold for scrap in 1923. The two survivors were relegated to ASW training at Portland

Isle of Portland

The Isle of Portland is a limestone tied island, long by wide, in the English Channel. Portland is south of the resort of Weymouth, forming the southernmost point of the county of Dorset, England. A tombolo over which runs the A354 road connects it to Chesil Beach and the mainland. Portland and...

, where their high performance led to them (literally) running rings around naval trawler

Naval trawler

A naval trawler is a vessel built along the lines of a fishing trawler but fitted out for naval purposes. Naval trawlers were widely used during the First and Second world wars. Fishing trawlers were particularly suited for many naval requirements because they were robust boats designed to work...

s whose performance their crews found deficient. R-10 was sold in 1929, while R-4 survived as a fast underwater target at Portland until 1934.