that picture wasnt an torpedo, it was JAWS, Rumdumdum...dumdum....dumdumdumdum
On Topic: If your torpedo hits an Sweat spot of the ship it will sink with one single torpedo, mostly I manage to cripple them heavy so I have to finsih them of with the deck gun
Love that , Fire Torpedo, hit Surface and man the Deck gun Yarrrrrr and blow him to kingdom come.