They tried that. They haven't figured out how to get the force field to stop forming at the water line. Force field surrounds ship, force field repels water around ship, ship drops to the bottom. Sad, really. Problem is, what they really need is a force field half-bubble. :-)
I must have slept through that part of my advanced defensive systems courses. .... *durn* It's SO obvious now that you pointed it out. :)
No, no.
You read the unclassified version of that story.
What really happened was that the force field bubble was formed all the way around the ship, but the ship floated up out of the water.
But they couldn't shoot missiles, torpedoes, or launch helicopters (to get off the "floating" ship and load supplies.
But when they turned off the force field, the bubble collapsed (naturally), and the ship came crashing down back down into the water from 150 feet up. This sunk a very expensive ship.