Re: 10K$ boat --- Are Insurance and Survey REALLY mandatory?
I would guess that the insurance which marinas themselves carry (for the customer boats) is something like "excess coverage" insurance. That is, the marina's insurance policy kicksin AFTER the first 1/4 million, or 1/2 million, or whatever amount the tenant is required to carry, and in the usual insurance rate manner, they marina pays a different premium based on when that coverage kicks in.
So if the marina requires you to carry 1/4 million of liability coverage, maybe they pay 1% of the value of the boats over that. If they require you to carry 1 million in coverage...maybe they pay 1/4% of the value over that. One way or the other, I expect the numbers are all a wash at the end. Either you're paying for your own insurance (not a bad idea) or your slip/storage rate is paying for it via the marina's overhead.
Unless of course you've got one of the marinas that simply carries no insurance, in which case if you've got none either...you're helixed. (A euphemism I'm forced to use in some PG-13 web forums.)
(Percents above taken from thin air, anyone who has real numbers, feel free to provide them.)