Britain's experimental bridge to postwar submarines

Explorer and Excalibur were British experiments with high-test peroxide and diesel propulsion. Their published speeds understated how aggressively the machinery could drive the boats, but that performance came with the risk of tearing the design apart. The A-class, originally ordered during the Second World War and represented today by HMS Alliance at Gosport, provided a more conventional postwar design. Britain therefore tested radical high-underwater-speed machinery while fielding a conventional class, in contrast with the American decision to keep modernizing wartime fleet boats as nuclear submarines took priority.