[Paul Riley]

I generally use impact exclusively in the early part of the war,and also in turbulent seas because magnetics have a tendency to prematurely detonate due to the current activating the sensitive warhead.
Magnetics are great for large ships and I reckon battleships,because you will want to cause massive damage as soon as possible in the latter case.And you are right about the force involved with mags,it is vented UP into the ship potentially breaking its back.
Like you ,I also prefer shots aimed at the ship's bow section allowing for forward momentum to HOPEFULLY cause the ship to flood.