HM Submarine, 'E' clas, 1912.
© Science Museum / Science & Society Picture Library
Model. More than 50 'E' clas submarines were built for the British Navy between 1912 and 1917. Of these, 27 were lost during World War I. The 'E' clas submarines were 181 ft long and were the first British submarines with internal subdivision by watertight bulkheads and also the first with beam torpedo tubes. The armament varied with three to five torpedo tubes and one 3-inch or one 12-pdr gun. Two sets of Diesel engines were fitted for surface propulsion, with electric motors for underwater work.