I just found this forum. I recently made the very unusual purchase of a Mark 8 Torpedo. It's in excellent condition and now sitting quietly in my garage. From what I understand, she is complete with gyro, radial engine, etc. I'd love to know more about these Torpedos, how they were powered, armed, controlled, etc. there isn't a lot of information about these Torpedos available and I'd love to make contact with someone who knows about them. I live in Sydney Australia. Steve.
See this page. 21-inch Torpedo Mk.VIII (Demonstrator) Have you tried contacting the Royal Navy Submarine Museum? Royal Navy Submarine Museum In Australia, you could also try contacting the Australian National Maritime Museum, Holbrook Submarine Museum, or the Western Australian Museum - Maritime. The first and third have Oberon class submarines on display, while the second has the upper hull casing and sail of an Oberon on display. If they don't have the information you are looking for, they should at least be able to point you in the right direction to find it.
A good place to start on such things is: Naval Weapons of the World - NavWeaps For British torpedoes the subpage of interest is: Torpedoes of the United Kingdom/Britain - NavWeaps They are not always correct but give enough sources that you can research to pretty much as much detail as you wish.
Wonderful. Thank you so much for your advice. I enjoyed reading the information in the first link. Very appreciated. Steve.
The British Mark VIII, AFAIK, used a 4-cylinder radial engine, the American Mark 8 used a steam turbine. That is why I gave him British sources rather than American.