J class

The J class submarines, was an attempt by the Royal Navy to have a submarine that was able to navigate on the surface with the rest of the fleet. The reason for this specification were reports that Germany had built submarines that could accompany the fleet with a speed of 22 knots. J class boats had a light cruiser hull form and was given three propellers. They also had three diesel engines for surface navigation and two electric motors for submerged navigation. The maximum surface speed was about 19 knots, too slow to accompany the Fleet, so finally its use was the same as the rest of submarines. It was the first British submarine class to have four torpedo tubes at the bow, as well as two at the stern. Seven units were built, six of which were transferred to the Australian Navy in 1919. The transferred submarines were in such dire condition, that were removed from service in mid-1921, after spending a huge amount of money to repair them and put them into service.

J class gallery amd more info


Información adicional

Ficha Completa
Country of origin

United Kingdom


Submarine (conventional propulsion)

Entered service




Displacement, (full load)

Surfaced: 1,204 tonnes – Submerged: 1,820 tonnes

Dimensions (length x beam x draught)

84.00 x 7.04 x 4.30 meters

Power plant

3 diesel engines, 1,200 hp each + 2 electric motors, 675 hp each

Power, (total)

3,600 hp + 1,350 hp

Shafts - Screws

3 shafts – 3 screws


Surfaced: 19 knots (35 km/h) – Submerged: 9.5 knots (17 km/h)

Diving depth, (maximum)

90 meters


90 tonnes of diesel


5,120 n. miles (9,472 km) at 12.5 knots

Main guns

Originally: 1 x 76mm gun – Later; 1 x 102mm gun


6 x 457mm torpedo tubes