Working from the Genesis flood narrative, along with the genealogies surrounding it, we can estimate that 55-75 years would have passed between God revealing his genocidal plan to Noah and the first drops of deadly dihydrogen monoxide.
If Noah had immediately started buying up flood insurance policies after getting the news, he'd have been on the hook for 660 to 900 months of premium payments before he could file any claims. And of course once the flood happened, all the insurance companies (and any courts to sue them in) would be gone, all existing currency would be worthless, and there would be no one to trade with anyway but his own wife and kids.
A MUCH BETTER PLAN
would be to SELL flood insurance for those several decades, knowing that there'd be NO flood until the one which God guaranteed would wipe out all his policyholders. Then he could have hired a bunch of poor doomed shmucks to build the ark while he and his family lived like kings. He could have even offered them all lavish retirement plans, to start just one month after they finished all the work.