Eric is right if you add it to your existing policy but sometimes a little insanity is good for the soul.
I can only speak for State Farm, but one option is to have your agent write a seperate personal article policy, sometimes called an "all perils" policy to cover your gear. About $26K in coverage currently cost $260US a year, no deductible. If you have a claim it does not effect your homeowners and there is no surcharge (upper) on the personal articles policy. (According to my agent) They can choose not to renew you if your gear keeps falling off the boat but it wouldn't effect your homeowners. It would be separate insurance as Eric suggests.
It's worth a phone call to your agent to get a quote and to ask the questions that Eric rightly raises. I'm guessing that coverage costs varies depending on your area, length with the company, phase of the moon, etc.
Disclaimer; I'm not an isurance guru and no one in their right mind should ever consider taking legal advise from me.
Cheers,
Steve