In the late 1920's and early 1930's it was decided that two main type of patrol submarine would meet the future requirements of the Long Range Overseas Patrol Submarine, a medium sized type for confined waters and a slightly larger one for overseas.

Having learned from past experience that external fuel tanks were not ideally suited the decision was taken that all future construction of submarines should have their fuel tanks internally built.   It was intended to maintain the quick diving and the manageable handling of the 'H' class whilst submerged, combined with the long range qualities of the 'O','P' and 'R' classes.

The result was the 'S' class. This class was in production for over 15 years and was the largest single group of submarines built for the Royal Navy.

There were three distinct groups in this class with varying differences as will be seen within the class notes and individual boat profiles.

Technical Information