But most executives that have large yachts probably have clever tax accountants that manage to claim that the "boss" is working while on board and the boat is just another business expense (office space, entertaining clients, business meetings, etc.) and are able to write a lot of it off. The two weeks cruising with the family is the only part he actually has to pay for (and maybe not even that).
I am sure some are but I think you'd be shocked how rare that is today. They know that this is an area carefully reviewed and a pet peeve of IRS agents. They also know that if questionable practices on yachts are shown then a lot of other detail to be reexamined. The entertainment deductions are way down over what you saw 30 years ago. Not to get into all the details and complications but the rules have changed dramatically including those for allocating expenses.
Examination of all travel and entertainment is a very strong focus of audits and of programs to push returns for review. Then when you toss in private planes or boats, only gets worse. I know someone in South Florida who was sold a bill of goods on tax accounting by a yacht broker. His accountant refused to agree to it. He fired his accountant, found one who would, took the deduction, got audited, lost and substantial penalties. Initially IRS said "attempt to defraud" rather than just claiming erroneous deduction but settled for just normal underpayment penalties and interest.
The other area to be careful is what charter brokers try to sell on setting up charter businesses. It often takes several years for those to backfire but then they go back and look at prior years. They also do that on the entertainment and business deductions discussed above. So, the real risk is you get audited, you lose the deduction going years back and pay the penalties which are quite high for the old years.
And, for the record, we do some work on our boats, we attend meetings by web cam sometimes, and many of our guests are employees, and we don't take a tax deduction at all. We could take some if we chose, but the reality is it's for pleasure and the business aspect is for our convenience. We have no space that is solely business and to split out the communications would be a major task for a little savings.