1915 - 1926: K Class
K Class submarines were the most bizarre and ill-fated submarines of the First World War period. Their conception, in the spring of 1915, arose from the demand for a submarine that could accompany the Grand Fleet at speeds of up to 24 knots.
A 1913 Admiralty design was adopted and, given the outline particulars, form and general arrangements, Vickers were requested to proceed with the detailed drawings.
The first-of-class K3 was laid down by His Majesty the King in May 1915 and was completed at Vickers within 15 months of being ordered. As a result of her trials, additional fans were fitted in the turbine room to combat the very high temperature generated by the steam turbines.
Of the 17 of the class, six were built at Vickers, each at an estimated cost of £340000. Originally 28 K Class submarines were ordered, but of these several were later cancelled, K18 to K21 were redesigned and became the M Class and K26 was an experimental submarine, built in an attempt to overcome the defects of the earlier K boats.
At the time, they were not only the largest submarines in the world, but also the fastest - their phenomenal speed being attained from 10 500 shp oil-fired steam turbines. In addition to the steam turbines, the class had an auxiliary diesel generator for charging the batteries and powering the electric motors.
The pioneer vessels of the K Class had a flush deck with a slight sheer forward but, because of a tendency to dive into head seas, later boats were redesigned to overcome this alarming habit and were fitted with large clipper bows and buoyancy tanks.
In order to allow this change, the armament and torpedo tubes were rearranged - the guns were removed to the superstructure and, where fitted, twin 18-inch deck tubes for use on the surface at night were removed.
The outline of the K boats was broken by two small funnels, which were hinged to fold down into a watertight well. The large air-intakes for the two oil-fired boilers also required watertight seals.
In the concise words of a contemporary submariner, the K Class had 'too many damned holes', and a minor obstruction or wire rope was sufficient to jam a vent open just as the submarine was ready to dive. An added disadvantage was that the highly ingenious design of the class was so complex that it was vulnerable to small defects.
K Class submarines could submerge faster than any previous steam submarines, but the delay was still impossibly long. Although the specified time to close down and secure the boiler room, funnel, etc. was only 30 seconds, the class still took about five minutes to dive. Once submerged, the class could dive to a depth of 200 feet.
The K boats, being high-speed Fleet submarines, were fitted with a deckhouse built over and around the conning tower, forming, in fact, a fully-enclosed bridge and giving, for the first time in Royal Navy submarines, protection to bridge personnel other than by canvas screens.
K Class submarines began to enter service in 1916, but because of their role with the Fleet they were unduly exposed to the risk of collision and a chapter of accidents befell the class. The worst accident occurred on the night of 31st January 1918 when ten K boats were operating with battle cruisers on a night exercise off May Island.
During the night, the helm in K14 jammed to starboard and she swung round and collided with K22, which was actually the K13 renamed after she had drowned most of her crew on her maiden voyage. The two boats locked together and in a series of collisions K4 was sunk by K6 (losing all hands), and K7 was sunk by HMS Fearless (also losing all hands). Four other submarines were damaged. This incident added further to the suspicion of a hoodoo on the class, because just two months earlier K1 had been sunk by the gunfire of HMS Blonde off the Danish coast.
These disasters finally sealed the fate of the K Class submarines and most were taken out of service at the end of the war.
The class never had an opportunity to prove themselves as Fleet submarines only six of the 17 boats built were in commission for six years or more, and the maximum time in service was nine years. However, experience gained from the K Class led to the building of the experimental submarine K26.