Somebody get Randall Munroe on the phone - I think we've found the next What-If topic.

Which makes me think - what about using all these choppers to blow the water in - and keep it there? :).

(I assume this is an equivalent problem to the lifting problem, as the extra pressure they'd be fighting would be that of the ship displacing water.)

That's actually an interesting idea - set up a temporary lock/dam on either side of the ship to float it. If, instead of a boring dam made out of concrete or something "normal" we used a fleet of Chinooks then all the better!

I do believe this is probably one of the solutions that's being investigated but I also believe it's

1. Super expensive to construct an impromptu dam under water

2. Floating a listing ship can result in more severe listing if you're not careful (See, for instance, the fact that when a ship beaches itself while the tide is out it's initially bad news - and when the tide starts to come back in it becomes significantly worse news.

Learning and humor are fun together!