Remember the Costa Concordia, that cruise ship that ended up on its side just off the coast of an Italian island? Well apparently there are now plans to salvage it by re-floating it:
http://youtu.be/71AuW7kHQsY
Makes sense,shallow waters I guess
Wouldn't be the first cruise ship or ferry to do so
Sounds like a lot of work to get it back to floating again. I'm surprised they don't just get some underwater welders to close off as many compartments as possible, then pump as much of the water out as possible. Who knows, maybe that'd be more expensive.
I think most of the work is being done to make sure it won't slide further into the ocean, and to protect marine life. If they didn't care at all about the marine environment, they could probably skip a lot of the steps..
Tie it down, tack on the air floats, and fill em up.