Advertising and promotion. Perfect tax shelter.

That's way different than you or I letting "Acme Towmotor Valve Rebuilding, Inc." purchase our boat.

My business has been audited twice. Mostly a clean bill of health, but I was denied "advertising" expenses for buying softball shirts for my kids teams. IRS challenged me to show them how my company name on some kids' shirts could possibly be advertising since my closest customer is 100 miles from where my kids play ball. My business name on the side of my boat - still not advertising. )I can donate money to my kids' scout programs or any other nonprofit and deduct that, though).

You are specifically mentioning a boat or vehicle used in a promotional or advertising fashion. Yes, those are deductible and are allowed. If the business owner, hovever, is proven to have used the vehicle for personal purposes in a non-promotional fashion or non-business usa, then the IRS will disallow some of the cost and maintenance of that vehicle.

Now, if you want to talk about boatd or yachts owned by corporations, they must show a certain amount of business usage for the company to be allowed to own it (board meetings, customer entertainment, charter service as an investmentm etc). Personal usage is taken out of the expenses.

Not saying that people don't do it. Just saying that I don't think it will hold water in an audit.

If you KNOW somehow that you will NEVER be audited, you can claim deductions and expenses that are ridiculous, you can under-report your income, you can even NOT file a return OR pay any taxes. That doesn't mean it is okay or legal.

Play it however you want it.
I own businesses. I own boats, bikes, cars, and toys. My businesses only own vehicles that can be shown to be for primarily company usage. That doesn't mean I can't use my business truck to haul mulch to my house. It also doesn't mean I can't use my personal boat for business use.

It does kind of mean that I can't just decide to let my businesses own my personal vehicles cause I own the company and I want to do it. It would be nice for it to work like that, but it really and truly doesn't.