HMS H5 was a British H-class submarine of the Royal Navy that served in the First World War. The boat, which was launched on 1 April 1915, was lost after being rammed by a British merchant ship off Caernarfon Bay in March 1918. It had been mistaken as a German U-boat and sank with the loss of all hands.

Design

Like all pre-H11 British H-class submarines, H5 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. H5 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 carried eight 18 in torpedoes. She is a Holland 602 type submarine but was designed to meet Royal Navy specifications. Her complement was twenty-two crew members.

Service record

On 14 July 1916 H5 spotted the SMU U-51 leaving the Ems and torpedoed her. U-51 sank with the loss of 34 of her crew; four men survived.

Sinking

HMS H5 was sunk after being rammed by the British merchantman Rutherglen when mistaken for a German U-boat on 2 March 1918. All on board perished including a US Navy observer, Lieutenant Earle Wayne Freed Childs from the American submarine AL-2. He became the first US submariner to lose his life in the First World War. All on board are commemorated on Panel 29 at Royal Navy Submarine Museum. The wreck's site is designated as a controlled site under the Protection of Military Remains Act. In 2010, a plaque commemorating the 26 crew was dedicated on Armed Forces Day in Holyhead.