HMS E21


HMS E21 was a British E class submarine built by Vickers, Barrow-in-Furness. She was laid down on 29 July 1915 and was commissioned on 1 October 1915. E21 was sold on 14 December 1921.

Design

Like all post-E8 British E-class submarines, E21 had a displacement of at the surface and while submerged. She had a total length of and a beam length of. She was powered by two Vickers eight-cylinder two-stroke diesel engines and two electric motors. The submarine had a maximum surface speed of and a submerged speed of. British E-class submarines had fuel capacities of of diesel and ranges of when travelling at. E21 was capable of operating submerged for five hours when travelling at.
E21 was armed with a 12-pounder QF gun mounted forward of the conning tower. She had five 18 inch 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 power ratings; in some submarines, these were later upgraded to systems by removing a midship torpedo tube. Their maximum design depth was although in service some reached depths of below. Some submarines contained Fessenden oscillator systems.

Crew

Her complement was three officers and 28 men.