Will my policy cover my trailer and other equipment?
Perhaps. All policies are different and while some may provide that as standard coverage, others provide it as an optional coverage.

When I got in a boating accident, I also lost some of my things that were on the boat. Are they covered?
Usually personal property is covered under the policy.

I got in a boating accident. My boat is okay, but unfortunately, the other boat isn't. Is that covered?
Yes. Most boatowners policies offer liability coverage.