Years ago, (I'm talking 50s and 60s) there was a form that you could fill out and get the tax back for boat use. I think they did away with this.
I know charter boats are run as a business and they deduct expenses, and I think they get the whole road tax back.
I don't see why GLF couldn't be set up as a internet business, and the boat used to advertise and take members fishing. The boat is a big part of GLF. Al fuel used in business vehicles is deductible, and I think you get the tax back also. The whole thing. Mo than one way around the barn.