BP,
You forgot something.
I knw a man with a shed load of Mk 1c's and a mate has a lot of Mk 30s. The latter will be much more environmentally friendly as they don't create as much noise churning the water and, unlike those later active torpedoes won't disturb marine life with noisy accoustic pings.
Mind you, might have to ditch the 1c actives 'cause they ping.