IABL : if you haven't already done the E-class submarine, these pictures can maybe help you :
Moreover I think the G-class submarine would be interesting to add, as it was active in the North Sea and German Bight and they were, if i am not mistaken, the second most numerous british (active) submarines of WW1 (14 subs).
http://en.wikipedia.org/wiki/British_G-class_submarine