Arguably Britain's best submarine of World War I, the E-Class was a logical progression in development from the D-Class. These boats were larger in displacement and were the first British submarines to incorporate transverse bulkheads, which divided the submarines internally into three compartments. This offered better survivability in the case of flooding.
The outbreak of World War I led to an expanded programme of submarine construction. The Emergency War Order of November 1914 called for the building of 38 E-Class submarines. As war production got going, construction times nearly halved over those built pre-war.
E-Class design characteristics
El was laid down in 1912, and E56 was completed in 1916. There are enough design differences to segment the E-Class into three groups: El through E8, E9 through E20, and E21 through E56. They were built by government and private shipyards, with two (AEl and AE2) being supplied to Australia.
The E-Class submarines built up to 1914 were fitted with only a single forward tube, one aft tube, and two transverse tubes amidships. The transverse tube was considered necessary because of the theoretical possibility of collision with the target when firing bows on. This design feature was never proved to be of any specific use and was largely abandoned in later classes. With the Emergency War Order, an additional forward tube was specified. Hence, from E9 onward, five torpedo tubes were carried. A minimum of one spare torpedo per tube was carried internally. Spare torpedoes could also be carried externally.
Unlike the earlier versions that were built, the later E-Class submarines were designed to be fitted with a deck gun as standard. During the war, a wide combination of gun types was adopted. The most common was the 12-pounder quick-firing gun, although several other types were used. Mountings were both of the fixed variety and the folding type, first adopted by the D-Class.
The six E-Class minelayers were fitted with ten vertical mine chutes that ran through the outer ballast tanks. Each carried one mine, allowing for the sowing of a 20-mine field. To enable this technology to be fitted, weight was saved by removing the two transverse torpedo tubes. In all other regards these submarines were standard to the E-Class design and could, therefore, operate offensively with gun and torpedo. Minelaying proved dangerous work because the mines themselves were volatile and the fields tended to be sown in the swept spaces of existing minefields. Any inaccurate navigation could prove disastrous.
An experiment to use E22 to carry Zeppelin intercepting aircraft in the North Sea was abandoned. However, aircraft carrying by submarine was to reemerge in the 1920s when M2 was converted to carry a small plane. Of particular note are the rapid advances that had been made in the reliability of diesel propulsion, which is clearly substantiated by the fact that the two submarines ordered by the Royal Australian Navy (AEl and AE2) were able to travel to Australia under their own motive power, something that would have been impossible a few years earlier. The Australian submarines ran for over 30,000 miles before the engines needed replacing.
E-Class submarines were fitted with 1kW wireless installations, which were later upgraded, in some cases, to 3kW The more powerful set could broadcast reports from the Bight. In order to house this equipment, one of the transverse torpedo tubes was removed. Certain E-Class boats were also fitted with Fessenden underwater signalling gear.
The seagoing qualities of this class marked an improvement over the D-Class. This was because the submarines were larger, had larger bridges, better freeboard, and increased reserve buoyancy. The increased size made for greater crew comfort as well. As the war progressed attempts were made to improve conditions on the bridge in rough weather. This led to the adoption of brass shrouds fitted around the conning towers.
Remarkably, the maximum diving depth of the E-Class, while specified to be around 100 feet, proved to be more than twice that in service. This proved fortuitous because deeper diving depths rapidly became necessary to avoid nets and minefields, as evidenced in the Dardanelles theatre.
During World War I the E-Class more than fulfilled the expectations of its designers. It was by far the most successful British submarine class in actions against enemy warships, which included the destruction of one battleship, three cruisers, five V-boats, and seven torpedo and gunboats. Three British commanders were to win the Victoria Cross in E-Class submarines. The E-Class submarine operated in all three major theatres of the war, and seven were sent to the Baltic.
