Problem solved, I used S3D editor to edit sim files and manually edited upc files in the Submarines folder. Destroyers used to have about 10-14 torpedos mounted sideways as well as many battleships. The English ones used 21 inch quadruple torpedo tubes mounted above water on both sides, so there is plenty to do make a war machine in SH4
Contrary to what the modders say, I cannot confirm that your ship will get destroyed if torpedos are launched, of course you need to be at slow speed.
XS