I'll have a 'T' please Bob.
Shame the RN boats never saw the same scale of operational usage and success of their US and german cousins, but considering what they did achive duing the war, they did well.
they sunk:
475 merchant ships, 105 warships and 36 submarines at the cost of 74 of their own.
The majority of the 74 RN subs on enternal patrol were actually lost to mines and accidents. The Italilans nailed quite a few of them in the Med though.