I know it's a bit off topic but I am astonished that, in this computerised age, so many torpedo designs fail to perform as well as wished.
Sidon and Kursk were sunk by HTP motor explosions. I'd guess, with modern electric battery technology, that unstable fuels would be passé.
The Kursk was sunk by an explosion related to the Shkval torpedo, really an undersea rocket capable of traveling 160 MPH underwater. No way could that be done with electric propulsion.
Jon