"Contract" is one of those educationese words that don't mean the same thing as in the real world. (Another favorite of mine is "rubric".)
In educationese, "contract" means "pledge", sort of. It'something you're pressured to agree to in exchange for nothing, with no stated penalties for breach (but horrible implied ones having to do with your immortal soul).
Re subs, the water has to be moved out of the way (and then back again afterward). That would require an insane amount of power for anything as large as a manned submarine. I strongly suspect this is meant for torpedoes only.
Re "wing in ground", I'm pretty sure you mean "wing in ground effect". Dirt is pretty draggy, y'know.