You need to buy the Series WW2 by Thems, its a great great great series.
Its 30 Episodes, each on 1 hour, and all 30 about WW2.
Its made in 1950's-1960's by Thems Production (Very High Quallety and Recognised Documentry Company of 1950's-1960's).
The Series Interwiev the Actual Leders of WW2, Leaders like Zuikov, Nimitz, Albert Spare, Dönitz, ect ect and also interwiev alot of Political Leders of WW2. The series interwiev leaders and political figures of all sides, and the only thing thay have in common is that thay had a Important Role in WW2 and still was alive in 1950's. It took them 8 Years or so to make the Series, and its truly something i recommend you to see, as the Actual Figures is there and talking, this means its no 2nd hand information, you will here the actual individuals say their opinion about alot of different subjects.// Im not 100% sure on all the equicmant thay used, i know thay produced many vertions of alot, and i think also you are correct that the "standard" torpedo used was lighter, maby arround 1000 or 1100 KG. (I know of a link who have some Torpedo Info:
http://www.navweaps.com/Weapons/WTJAP_WWII.htm ) -- I was pritty sure thay also made a hevy vertion? (But i might be incorrect then i guess) -- Anyway, You should regardless see the series, it is truly great, its very very very nice. [8D]