HMS E40

HMS E40 was a British E-class submarine launched by Palmer, Jarrow in 1916 and was completed by Armstrong Whitworth, Newcastle upon Tyne. She was launched on 9 November 1916 and was commissioned in May 1917.

During her World War I service while patrolling Scandinavian waters E40 encountered a U-boat. As the submarine dived the captain was hit with shrapnel and had to be dragged in; the hatch stuck and the vessel took on water, going straight to the bottom. After an hour the air was poor; with the captain unconscious, the first lieutenant asked the crew if he could use the remaining oxygen to try to raise the submarine. This succeeded and the E40 managed to get back to Middlesbrough where it had been posted missing, presumed sunk. The captain survived. HMS E40 was sold on 14 December 1921.

Design
Like all post-E8 British E-class submarines, E40 had a displacement of 662 LT at the surface and 807 LT while submerged. She had a total length of 180 ft and a beam of 22 ft. She was powered by two 800 hp Vickers eight-cylinder two-stroke diesel engines and two 420 hp electric motors. The submarine had a maximum surface speed of 16 kn and a submerged speed of 10 kn. British E-class submarines had fuel capacities of 50 LT of diesel and ranges of 3255 mi when travelling at 10 kn. E40 was capable of operating submerged for five hours when travelling at 5 kn.

E40 was armed with a 12-pounder 76 mm QF gun mounted forward of the conning tower. She had five 18 inch (450 mm) torpedo tubes, two in the bow, one either side amidships, and one in the stern; a total of 10 torpedoes were carried.

E-class submarines had wireless systems with 1 kW power ratings; in some submarines, these were later upgraded to 3 kW systems by removing a midship torpedo tube. Their maximum design depth was 100 ft although in service some reached depths of below 200 ft. Some submarines contained Fessenden oscillator systems.

Crew
Her complement was three officers and 28 men.