HMS H3

HMS H3 was a British H-class submarine built by Canadian Vickers Co, Montreal. She was laid down on 11 January 1915 and was commissioned on 3 June 1915. After commissioning she crossed the Atlantic from St. John's, Newfoundland to Gibraltar escorted by the armed merchant cruiser HMS Calgarian (1913). She was accompanied by HMS H1, HMS H2 and HMS H4. H3 was mined in the Gulf of Cattaro, Adriatic on 15 July 1916.

Design
Like all pre-H11 British H-class submarines, H3 had a displacement of 364 LT at the surface and 434 LT while submerged. It had a total length of 150 ft, a beam of 15 ft, and a draught of 12 ft. It contained a diesel engines providing a total power of 480 hp and two electric motors each providing 320 hp power. The use of its electric motors made the submarine travel at 11 kn. It would normally carry 16.4 LT of fuel and had a maximum capacity of 18 LT.

The submarine had a maximum surface speed of 13 kn and a submerged speed of 11 kn. British H-class submarines had ranges of 1600 nmi. H3 was fitted with a 6 lb Hotchkiss quick-firing gun (6-pounder) and four 18 in torpedo tubes. Its torpedo tubes were fitted to the bows and the submarine was loaded with eight 18 in torpedoes. It is a Holland 602 type submarine but was designed to meet Royal Navy specifications. Its complement was twenty-two crew members.