surfacing 'beam on' in heavy seas, and it became the practice to surface head-to-sea in rough weather whenever possible.
As with the Overseas Patrol Submarines, the Thames Class carried oil fuel in external tanks, but whereas the Overseas boats were fitted with troublesome riveted tanks, the tanks of the Thames Class were of welded construction and were very satisfactory, though leaks occasionally occurred inboard - through rivets in the thick pressure hull plating.
With the abolition of the stern tubes, the torpedo armament of the class consisted of six 21-inch bow tubes (with 12 torpedoes carried). A 4.7-inch gun was originally fitted, but in keeping with submarine policy of the period was changed, after completion, to a 4-inch QF gun with 120 rounds of ammunition.
