British K class submarine

The K class submarines were a class of steam-propelled 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 of 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...

 designed in 1913. Intended as large, fast vessels which had the endurance and speed to operate with the battle fleet
Naval fleet
A fleet, or naval fleet, is a large formation of warships, and the largest formation in any navy. A fleet at sea is the direct equivalent of an army on land....

, they gained notoriety, and the nickname of Kalamity class, for being involved in many accidents. Of the 18 built none were lost through enemy action but 6 sank in accidents. Only one ever engaged an enemy vessel, hitting a 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...

 amidships though the 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...

 failed to explode.

Design and development

In 1913 an outline design was prepared for a new submarine class which could operate with the fleet, sweeping ahead of it in a fleet action. At that time the only way which they could have sufficient surface speed, of 24 knots (44 km/h), to keep up with fleet was to be steam powered. In a fleet action, the submarines would get around the back of the enemy fleet and ambush it as it retreated.

The boats were to be 338 ft (103 m) long and displace 1,700 tons on the surface. The design was not proceeded with until results from trials of HMS Nautilus and Swordfish
HMS Swordfish (1916)
HMS Swordfish was an experimental submarine built for the Royal Navy before the First World War to meet the Navy's goal of an "overseas" submarine capable of on the surface. Diesel engines of the period were unreliable and not very powerful so steam turbines were proposed instead to meet the RN's...

 had taken place, and in the event a slightly smaller three-screw submarine, the 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...

, was designed. By the middle of 1915 it was clear that the J class would not meet expectations, in particular they would only reach 19 knots (35 km/h) — still less than the 21 knots (39 km/h) needed to accompany the fleet.

The K class design was resurrected and 21 boats ordered in August at a cost of £340,000 each. In the event only 17 were constructed in the first instance, the orders for the last four being cancelled and replaced by ones for the M class
British M class submarine
The British Royal Navy M-class submarines were a small class of diesel electric submarine built during World War I. The unique feature of the class was a 12-inch gun mounted in a turret forward of the conning tower.-Background:...


Six improved versions, K22 to K28 were ordered in October 1917 but the end of the First World War meant that only K26
HMS K26 was the only modified K-class submarine of Britain's Royal Navy to be completed. One of six ordered, she was laid down towards the end of the First World War but not completed until five years after its end....

 was completed.

The double hull design had a reserve of buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...

 of 32.5 percent . Although powered on the surface by oil-fired steam turbine
Steam turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....

s, they were also equipped with an 800 hp (0.6 MW) diesel generator
Diesel generator
A diesel generator is the combination of a diesel engine with an electrical generator to generate electrical energy....

 to charge the batteries and provide limited propulsive power in the event of problems with the boilers.

This pushed the displacement up to 1,980 tons on the surface, 2,566 tons submerged. They were equipped with four 18 inch (460 mm) 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 at the 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...

, two on either beam and another pair in a swivel mounting on the superstructure for night use. The swivel pair were later removed because they were prone to damage in rough seas.

They were fitted with a proper deckhouse built over and around the 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....

 which gave the crew much better protection than the canvas
Canvas is an extremely heavy-duty plain-woven fabric used for making sails, tents, marquees, backpacks, and other items for which sturdiness is required. It is also popularly used by artists as a painting surface, typically stretched across a wooden frame...

 screens which had been fitted in previous Royal Navy submarines.

The great size of the boats compared to their predecessors led to control and depth keeping problems particularly as efficient telemotor controls had not yet been developed. This was made worse by the estimated maximum diving depth of 200 ft (60 m) being much less than their length. Even a 10 degree angle on the 339 ft (103 m) long hull would cause a 59 ft (18 m) difference in depth of the bow and stern, and 30 degrees would produce 170 ft (50 m) which meant that while the stern would almost be on the surface, the bow would almost be at its maximum safe depth. The problems were made even more dangerous because the eight internal bulkhead
Bulkhead (partition)
A bulkhead is an upright wall within the hull of a ship or within the fuselage of an airplane. Other kinds of partition elements within a ship are decks and deckheads.-Etymology:...

s were designed and tested during development to stand a pressure equivalent to only 70 ft (20 m).


HMS K3 was the lead ship of the British K class submarines. She was laid down on 21 May 1915 by Vickers, Barrow-in-Furness. She was commissioned on 4 August 1916.In December 1916, K3, with the future King George VI aboard,...

 was the first of the class to be completed, in May 1916 and trials showed numerous problems. The most serious was the high temperatures in the boiler room which was to some extent alleviated by installing bigger fans.

Steaming at speed tended to push the bow into the water making the already poor sea-keeping worse. To fix this a bulbous swan bow was added. Nevertheless there were still problems, the most embarrassing being that in a heavy sea water could enter the boat through the twin funnel
A funnel is a pipe with a wide, often conical mouth and a narrow stem. It is used to channel liquid or fine-grained substances into containers with a small opening. Without a funnel, spillage would occur....

s and put the boiler
A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.-Materials:...

 fires out.

They suffered numerous accidents, largely caused by their poor maneuverability coupled with operating with the surface fleet, and which caused the loss of the following:
  • K13
    HMS K13
    HMS K13 was a steam-propelled First World War K class submarine of the British Royal Navy. She sank in a fatal accident during sea trials in early 1917 and was salvaged and recommissioned as HMS K22....

     sank on 19 January 1917 during sea trials when an intake failed to close whilst diving and her engine room flooded. She was eventually salvaged and recommissioned as K22 in March 1917.
  • K1
    HMS K1
    HMS K1 was a First World War steam turbine-propelled K-class submarine of the Royal Navy.She was sunk to prevent her from being captured following a collision with off the Danish coast. She had been patrolling on the surface as part of a flotilla of submarines operating in line ahead...

      collided with K4
    HMS K4
    HMS K4 was a British K class submarine built by Vickers in Barrow-in-Furness. She was laid down on 28 June 1915 and commissioned on 1 January 1917, one year before the end of World War I.- Accident 17 November 1917 :...

     off the Danish coast on 18 November 1917 and was scuttled to avoid capture.
  • Two boats were lost in an incident known as the Battle of May Island
    Battle of May Island
    The Battle of May Island is the name given to the series of accidents that occurred during Operation E.C.1 in 1918.Named after the Isle of May, an island in the Firth of Forth, close by, it was a disastrous series of accidents amongst Royal Navy ships on their way from Rosyth in Scotland to fleet...

     on 31 January 1918. The cruiser HMS Fearless
    HMS Fearless (1912)
    HMS Fearless was an Active-class scout cruiser of the Royal Navy. She was built at Pembroke Dockyard and launched on 12 June 1912.On commissioning she was assigned to the Harwich Force with her sisters, and was the leader of the 1st Destroyer Flotilla...

     collided with the head of a line of submarines, K17
    HMS K17
    HMS K17 was a British K class submarine built by Vickers in Barrow-in-Furness.- Loss :K17 was sunk on 31 January 1918 during the night time fleet exercises later known as the Battle of May Island when she was attached to the 13th Submarine Flotilla. ploughed into K17 at the head of a line of...

    , which sank in about 8 minutes, whilst other submarines behind her all turned to avoid her. K4
    HMS K4
    HMS K4 was a British K class submarine built by Vickers in Barrow-in-Furness. She was laid down on 28 June 1915 and commissioned on 1 January 1917, one year before the end of World War I.- Accident 17 November 1917 :...

     was struck by K6
    HMS K6
    HMS K6 was a British K class submarine built by HM Dockyard, Devonport. She was laid down on the 8 November 1915 and commissioned in May 1917.K6 was the first of the K class to have its bows raised by converting it into a bulbous swan shape....

     which almost cut her in half, and was then struck by K7
    HMS K7
    HMS K7 was a K class submarine built by HM Dockyard, Devonport. She was laid down on 8 November 1915 and commissioned in July 1917.K7 was involved in the accident with the 4th Light Cruiser Squadron. She was also involved in the Battle of May Island exercise...

     before she finally sank with all her crew. At the same time K22 (the recommissioned K13) and K14
    HMS K14
    HMS K14 was a K class submarine built by Fairfields in Govan, Scotland. She was laid down in November 1915, and commissioned on 22 May 1917....

     collided although both survived. In just 75 minutes, two submarines had been sunk, three badly damaged and 105 crew killed. {HMS K4 ran aground on Walney Island
    Walney Island
    The Isle of Walney, also known as Walney Island, is an island in the United Kingdom which lies off the west coast of England, at the northern tip of Morecambe Bay. It forms part of the Borough of Barrow-in-Furness, and it is separated from the mainland at Barrow by Walney Channel, a narrow channel...

     in January 1917 and remained stranded there for some time.}
  • K5
    HMS K5
    HMS K5 was one of the K-class submarines that served in the Royal Navy from 1917-1921. She was lost with all hands when she sank en route to a mock battle in the Bay of Biscay.-War service:...

     was lost due to unknown reasons during a mock battle in the Bay of Biscay
    Bay of Biscay
    The Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...

     on 20 January 1921. Nothing further was heard of her following a signal that she was diving, but wreckage was recovered later that day. It was concluded that she exceeded her safe maximum depth.
  • K15
    HMS K15
    HMS K15 was a K class submarine built by Scotts, Greenock. She was laid down on 19 April 1916 and was commissioned on 30 April 1918.K15 sank due to an accident, when moored alongside the light cruiser at Portsmouth Harbour on 25 June 1921. She was then salved in July 1921. K15 was sold in August...

     sank at her mooring in Portsmouth
    Portsmouth is the second largest city in the ceremonial county of Hampshire on the south coast of England. Portsmouth is notable for being the United Kingdom's only island city; it is located mainly on Portsea Island...

     on 25 June 1921. This was caused by hydraulic oil expanding in the hot weather and contracting overnight as the temperature
    Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

     dropped and the consequent loss of pressure
    Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

     causing diving vents to open. The boat flooded through open hatch
    Hatch may refer to:* Hatching, also called "cross-hatching", an artistic technique used to create tonal or shading effects using closely spaced parallel lines* Hatching, the emergence of a young animal from an egg...

    es as it submerged.

Dive time was around 5 minutes, with the record being 3 minutes 25 seconds which was claimed by K8
HMS K8 was a British K class submarine built by Vickers, Barrow-in-Furness. She was laid down on 28 June 1915 and was commissioned on 6 March 1917. K8 was sold on 11 October 1923.- References :...

. The leisurely time allowed the captain
Captain (naval)
Captain is the name most often given in English-speaking navies to the rank corresponding to command of the largest ships. The NATO rank code is OF-5, equivalent to an army full colonel....

 the luxury of being able to walk around the superstructure to ensure that the funnels were securely folded.

The last, improved, boat, K26 was completed slowly, finally being commissioned in 1923. She had six 21 inch (530 mm) bow torpedo tubes but retained the 18 inch (460 mm) beam tubes. Her higher casing almost cured the problems of seawater entering the boiler room and improved ballast tank arrangements cut the diving time to 3 minutes 12 seconds to get to 80 ft (24 m). She also had an increased maximum diving depth of 250 ft (75 m).
Most were scrapped between 1921 and 1926 but K26 survived until 1931, being broken up because her displacement exceeded the limits for submarine displacement in the London Naval Treaty
London Naval Treaty
The London Naval Treaty was an agreement between the United Kingdom, the Empire of Japan, France, Italy and the United States, signed on April 22, 1930, which regulated submarine warfare and limited naval shipbuilding. Ratifications were exchanged in London on October 27, 1930, and the treaty went...

 of 1930.

K18, K19 and K20 became the new M class submarines. K21, K23, K24, K25, K27 and K28 were cancelled.

Although the concept of a submarine fast enough to operate with a battle fleet eventually fell out of favour, it was still an important consideration in the design of the Thames class in the late 1920s.

External links

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