Suggest some people actually bother to READ about The British Submarine campaign and their torpedos etc - before making snap
judgements about weather or not it would work in SH.
http://home.cogeco.ca/~gchalcraft/sm/attack.html
@ Dan, should the need ever arise; the best bet is to email the Royal navy Submarine Museum for any accurate information regarding RN subs.
Their email address for such enqiries is:
archives@rnsubmus.co.uk - more details here:
http://www.rnsubmus.co.uk/contact/historicform.html
(have emailed them once before and they are pretty helpful)