RE: Underwater questions [ot]

>Okay, would high enfinshancy (sp?) fuel cells work?

Assume fusion power as in Hammers Blowers - basically limitless
you could then envisage some sort of caterpillar drive as in Hunt
for Red October. A mini version could power the torpedoes.

>I was thinking of an Aerobraking based insertion, would it 
>work to have lateral movement when it hit the water?

VTTBS flying sub would be the way to go, this is SF.

>Would a KEP type weapon be practical?

Do you mean an orbital THOR type weapon?

A rail/gauss gun with a Fin Stabilised round 
might work, you could invent a forcefield to keep the water out of 
the electrics or have them waterproofed. It would be short range
due to friction. Something like a high energy harpoon gun. 

Oher weapons could be invented to foul your opponents engines or
jets - like a cloud of stuff that if ssucked into the vents
disables the sub.

Someone mentioned SUBROC type standoff torpedoes they'd work too.
Rocket boost on surface to target area then - sonar to seek and 
destroy.

>Hedgehog?

WWII anti-sub weapon basically a mortar that fires contact fused depth
charges - they only go off if they hit a sub.