Earlier quoted context omitted.
I'd be amazed if the density of weight on the ship is such that an arbitrarily large fleet of Chinooks could actually safely accomplish this. And helicopters flying in a dense formation under strain is quite likely to result in a lot of really big problems.
The rotor wash beneath it all would be breathtaking.. and might blow all the water out of the canal. :)
(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.)