About the only good reason to say Mayday is to break in to a channel clobbered with other calls, but that is not what I cam here to post.
Here is a link to a slideshow of photos taken as the bird was lifted from the water:
Crews hoist ditched plane from Hudson River | IndyStar.com gallery | The Indianapolis Star
These show a baggage compartment door open. I suspect the divers opened this to expedite water escaping during the lift to the barge. Had this happened at impact, the door probably would have been ripped off, or at least twisted and mangled.
Some photos also show the tail cone is missing. Given the fact that from the videos of the landing, it looks like the tail hit first, I suspect maybe the divers didn't remove it, rather the impact probably did.
I wonder if losing the tail cone would negate the benefits of sealing the plane up with the ditch switch, which according to several reports was not activated in this incident.