It depends on the size of the boat and how it's powered. If it's over 50 horsepower it's excluded. Likewise, craft that are used in or practicing for any race or organized competition, rented to others, carrying people/property for a charge, or a sailing vessel over 26 feet in length and owned by or rented to the insured are all excluded from coverage. Look at the watercraft liability section of the policy; that details what's excluded or covered.  Remember liability coverage applies to bodily injury or property damage to others, not damage to the boat itself. The damage to property of others section specifically excludes damage arising out of the ownership, maintenance, use, loading or unloading of watercraft. The watercraft liability exclusion is on page 17 or 18, depending on the edition of the policy if you're using the ISO HO 00 03.