HM Submarine X1 was conceived and designed as a submersible commerce raider for the Royal Navy; at the time of her launching she was the largest submarine in the world. The idea of a submarinecruiser had been proposed as early as 1915, but was not put into practice until 1921. X1, which was based on the uncompleted German U-173 class of 2,000-ton "U-Cruisers", was laid down on 2 November 1921 at the Naval Dockyard Chatham and completed on 23 September 1925, commissioning in December 1925.
The 1922 Washington Naval Treaty, of which Britain was a signatory, did not ban submarines but it did ban their use against merchant ships, which was X1s unacknowledged purpose; its armament had been designed to successfully engage the classes of vessels likely to be escorting convoys, such as destroyers and frigates. Therefore, a certain amount of secrecy surrounded X1, the government even going to the lengths of taking a national newspaper to court over its pictures of the new submarine following her launch, all copies of the paper being seized.
The X1s thick pressure hull was in diameter amidships, and was divided into 10 water-tight compartments. This was almost completely surrounded by her external hull which also contained the main ballast tanks and most of her fuel. Her intended maximum diving depth was but was reduced to once in service.
She was expected to sink her targets using gunfire and so was given four... Read More