X.1: The Royal Navy's Mystery Submarine by Roger Branfill-Cook
English | 17 Jan. 2013 | ISBN: 1848321619 | 192 Pages | EPUB (True) | 26.55 MB
The 'X' stood for experimental, but it might equally have meant extraordinary, exotic or extravagant, as this giant submarine attracted superlatives - the world's largest, most heavily armed, and deepest diving submersible of the day.