Experimental Submarines

K Class

Group One

  • K Class Submarine
  • K2
  • K3
  • K5
  • K6
  • K14
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The 'K' class were developed with the idea of being able to operate with the main battle fleet. The Admiralty had also heard a rumour that the Germans had a submarine capable of high surface speeds, this resulted in falling back to the steam turbine unit which was being installed in the experimental submarine Swordfish. They were the fastest and biggest submarines in the world, with a length of 330 feet and a beam of 26.5 feet, their speed was 24 knots provided by oil-fired steam turbines, driving twin screws. The two 5 foot high funnels were raised and lowered by an electric motor and hinged to fold down into watertight wells.

An unusual feature of this class were the fuel tanks, the underside of which were open to the sea, the oil floated on the water and was drawn by pumps from the top of the tanks.

The class became known as "The Kalamity Kays", for reasons which you will see as you look at each boats individual file, just to give you a taster:

In November of 1917 the 12th Flotilla of 'K's were operating with the Fleet off Denmark. During manoeuvres K4 rammed K1 and damaged her so much that the flotilla leader had to sink her by gunfire. In January of 1918 the 13th Flotilla based in Scotland, sailed with the Rosyth force of 3 battleships, 4 battle-cruisers, 14 light cruisers. Forty warships were to be taken through the narrow and congested waters of the Forth to meet up with Beatty's force from Scapa Flow, in the North Sea.They sailed in darkness, under radio silence and showing only one stern light. K11, 17, 14, 12 and 22 were being led by HMS Ithuriel, K4, 3, 6 and were being led by HMS Fearless. As they approached the Isle of May, just beyond the estuary, they ran into misty conditions which reduced visibility to about a mile.

It appeared K11 reduced speed and moved out of line, K14 reduced speed but maintained her course.K22 lost sight of K12 but rammed K14, both were badly flooded.Four ships of the 2nd Battle-Cruiser Squadron led by HMS Inflexible bore down on the two flooded submarines from astern, and the Inflexible smashed into K22 at 18 knots, both submarines remained afloat.

Whilst all this was going on the Ithuriel had picked up the distress call and turned back to help, followed by K12 and K17. The Fearless suddenly appeared ahead of the Ithuriel with her troop of K boats. The Fearless rammed K17 at 21 knots, the submarine sank.In the confusion which followed, K4 was rammed by K6 which cut the other submarine almost in two and sank her. In just a few hours two of the 'K's had been sunk and two more along with the Fearless badly damaged.

18 Built

K1, K2 and K5

HM Dockyard, Portsmouth
1915 - 1917

K3, K4 and K8 - K10,K17
Vickers, Barrow-in-Furness
1916 - 1917

K6 and K7
HM Dockyard Devonport
1915 - 1917

K11 and K12
Armstrong Whitworth, Newcastle-on-Tyne
1915 - 1917

K13 and K14
Fairfield, Govan
1915 - 1917

Scotts, Greenock
1916 - 1918

Beardmore, Dalmuir
1916 - 1918


Technical Information

1,883 sf
2,565 sm

Length (ft):
338 (loa)

Breadth (ft):

Draught/Height (ft):

10,500 hp geared turbines
800 hp diesel booster for diving or surfacing.
1,400 hp electric motor.
Twin screws.

Speed (kts):
25 kts sf
9 kts sm

Oil Supply (tons):

8 x 18 inch tubes, 4 bow, 4 beam. 1 or 2 4 inch guns, 1 x 3 inch AA gun.

960 miles at full speed.
12,500 miles at 10 kts sf.
30 miles at 4 kts sm.

50 - 60 officers and ratings.