I would never drive a boat without insurance. We even have captain insurance on it so if we have someone else driving , a captain, if he harms the boat all is ok. The boats REPLACEMENT value, not what we paid, is 600k we have it insured at purchase cost, the insurance is more than the cost of every car we have insured for a year and more than our house insurance.
In the insurance, for the marina, you need to have named storm removal, ie your boat sinks it will be recovered and removed, gas spillage , level must be at 900k plus, don't recall the limit, ice damage, if you have your boat winterized and the engines get ice damage you are covered. Etc etc
And of course running into someone else.
I did not see any mention of no fault in the policy docs.