On 26 February 1918, the British submarine HMS H5 sailed from Berehaven under the command of Lieutenant A. W. Forbes, Distinguished Service Order (D. S. O), with US Navy Liaison Officer Earle Childs on board for instructional purposes, and was expected to return to port on the morning of 6 March. On 2 March, however, the SS RUTHERGLEN reported at Milford Haven that it had rammed a submarine crossing its bow at considerable speed. This was the H5. There were no survivors.

This file includes papers regarding the loss of the H5.

Source:
ADM 137/2076. Commodore (S) war records, Volume X. Reports of proceedings of submarines attached to HMS Dolphin, HMS Vulcan, HMS Platypus, HMS Adamant, HMS Bonaventure and HMS Ambrose. ADM - Records of the Admiralty, Naval Forces, Royal Marines, Coastguard, and related bodies. The National Archives, Kew. n.p.