Well, yes. The potential liability is so high, private insurers won't touch flood insurance. That's why the Federal Flood Insurance program IS. (Which, technically, should be bankrupt or nearly so after Sandy.) The Federal program only covers up to a $250k loss for a residence and $500k for a business. Not much help for many, even if they had flood insurance.
I can't imagine the rates she'd need to pay to cover the flood insurance risk for a MARINA, which is in/on water to begin with.
Makes some sense for a business to maintain reserves to cover such eventualities. Or to move inland, if they can't handle the risk.
Since federal subsidies help with flood insurance, we all help pay for it in our taxes.