Jeff, unless you're totally sold on the boat...
Cancel the contract due to the problem and find another boat.
I've seen a couple of these with the same problem, and I just shake my head at Bene's answer. "just throw a hunk o' steel underneath, it'll be fine."
While it is true you do spread the load out under the mast, there isn't a lot of support built into the deck to begin with, so all you're doing is lessening the problem. I'm not a structural engineer, but you don't stand on a liliy pad, no matter how big the pad is.
This is just my opinion, that and .50 will get you a newspaper.
We are not primarily on earth to see through one another, but to see one another through
Some people are like slinkies: not really good for anything... but you can't help laughing when you push them down the stairs