Boat == “a hole in the water that swallows money.” If you want to live on one for fun, that’s fine, but don’t expect it to be cheap. Remember that it lives in a corrosive environment, so it needs quite a bit of maintenance.
From a strictly financial standpoint, best to buy a condo in the low $100k range (they exist) with common charges in the high $100 to low $200 range per month. At least theoretically, it’s an appreciating asset rather than a depreciating one.