The problem here is the size of the market, not the fact that people don't want to pay. I assume the market is fairly small (at least, I don't know that many pe

The problem here is the size of the market, not the fact that people don't want to pay. I assume the market is fairly small (at least, I don't know that many people who live on a boat) so it might not be worth your time for that reason. But I would be willing to bet that there are people ready to pay anywhere from $20 to $200 for a detailed guide or video course on how to live in a boat. In fact you could replace "live in a boat" with pretty much any skill you can think of ("play the ukulele", "get better at gardening") and I believe that would still hold true.