HMS H4

HMS H4 was a British H-class submarine built by the Canadian Vickers Co., Montreal. She was laid down on 11 January 1915 and was commissioned on 5 June 1915. After her commissioning, HMS H4 and sister ships HMS H1, HMS H2 and HMS H3 crossed the Atlantic from St. John's, Newfoundland to Gibraltar being escorted by the armed merchant cruiser HMS Calgarian (1913). H4 sank the U-boat SMU UB-52 in the Adriatic on 23 May 1918. She was sold on 30 November 1921 in Malta.

Design
Like all pre-H11 British H-class submarines, H4 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. H4 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.