When you buy a real
marine policy (as opposed to auto insurance companies that also insure boats) the insurance company will ask what
layup period you want and they will usually quote a lower
price if there is a significant
layup period, say 4 to 6 months out of the year.
This doesn't mean that you don't have insurance during this period. You do and it will satisfy your marina. But the risks of
hull or liability loss are much less during the layup period and so they will give you a lower
price.
This is SOP in the northeast.
David