Ok here is the deal. I am Running a game based off of a submarine that I pulled out of the back of my mind.
She has a semi rigid skeleton. I think she is 150m long and about 30 across and about 15 high at the apex. She is powered by a very large set of 2 hydrogen fuel cells, tapping the voltage off the hydrogen exchange. She is propelled by a 4 bands of 6' long cilia along the periphery and at about 30 degree intervals along the longitudinal axis.
she carries 8-12 torps and has a respectable compliment of anti ship missiles.
My thinking is that she would be VERY fast and manageable in the water, and that her skin could absorb most of the acoustic noise of the chassis. in the water she would sound more biological than mechanical. Oh yah over all fore to aft she can flex 10 degrees.
I guess mostly what I am looking for here is the speed/handling numbers. Oh and signal.