and Clyde, in 1935. The original intention was to construct 20 Thames Class submarines for the Royal Navy, but a change of policy in 1933 prevented this.
Built at a cost of over £500 000 each, the large and comfortable Thames Class were partial double-hull boats with a pressure hull of 'keyhole' section.
In an attempt to keep down weight so as to obtain the required speed, the design diving depth was reduced from the 500 feet of the Odin Class to 300 feet, with the result that the pressure hull plating was reduced to 25 lb/sq inch as opposed to 35 lb/sq inch in Odin.
To propel the Thames Class at the unusually high surface speed
