Nice article, 6pack, and it does sound like this arrangement has worked out for them. We’ve owned boats for years, and know lots of people who do–primarily for recreational use.
Those we have known who have lived on their boats exclusively, have all ended up selling their boats, and returned to their homes after a year or two–citing many reasons for doing so. Some even tried the seasonal thing–moving their boats to the Bahamas, Lauderdale, the Riviera, etc.–yet even they again resorted to solid ground in the final analysis.
For the purpose you’ve mentioned, I agree with CAR in, that, another type of investment would make a lot more sense with regard to your son, that is, unless, you, and the rest of the family plan to also use the boat recreationally.
I definitely would not enter into this lightly, and would do a lot of research before you make your final decision.