[Bosje]

and at close range (around 1 kilometer) when the ship runs more or less perpendicular across your stern or bow, this trick also applies:

set all torpedo data to 0 so that it fires exactly on you bearing. fast torpedo leads by target speed in degrees, slow torpedo leads by the target speed x2

a destroyer, for example, crossing your bow at 15 knots after its attack run, needs a fast running torpedo aimed 15 degrees in front of her

this is what I always use when I am inside a convoy and the poo hits the proverbial propellor

edit: ah there is a list of lead angles on that link above. never mind (although I find my numbers are close enough to kill stuff)