torpedo damage

[jgf]

I can sink a heavily armored battleship with four torpedoes. Why does it take six torpedoes to sink a comparatively lightly constructed and completely unarmored passenger ship? I would think four torpedoes would practically blow it apart.

It may take one, two, or three torpedoes to sink a C3 cargo ship. One may slow it a knot or so; a second may sink it but more likely will slow it further and probably start fires; the third will sink it (though if the situation permits I prefer using the deck gun). BUT (and this happens so consistently I'm convinced the game is cheating) if I fire a salvo of two or three torpedoes, the first will sink the ship and the other(s) are wasted (they are fired about ten seconds apart so it's not a case of two hitting near simultaneously).