i was denied on my boat policy?

Your first step is understand why they denied coverage.  If there is a formal letter denying coverage, read the part of the policy that the insurance company is relying on.  Does that language apply to your claim?  Or not?  If the insurance company is wrong based on the "plain language' of the policy, that is the first thing to determine.  If you have any questions, then talk to your agent who sold you the policy.  If he or she thinks the insurance company is wrong, then they might be able to get them to change their mind.  If the loss is valuable enough, and you don't think that the policy properly insured you, you may need to see a lawyer.