HMS Churchill (S46)

HMS Churchill was the first of three Churchill-class submarine nuclear fleet submarines that served with the Royal Navy.

Propulsion
Churchill was chosen to trial the first full-size submarine pump jet propulsion. Trials of a high-speed unit were followed by further trials with a low-speed unit, and these were successful enough for the same propulsion to be fitted in the rest of the class. Later British submarine classes also featured the pump jet, although first-of-class vessels Swiftsure and Trafalgar were fitted with propellers at build.