Considering how much damage a renter could do in just one day, how expensive the vessel would be, how expensive or complicated it would be to obtain commercial insurance
or to have the renter obtain adequate assigned-payee insurance
I think you'd find that only a terribly casual or more likely, totally irresponsible person, would be willing to give their boat
to a stranger for a month, or even for a week, without a damned good reason or being in a formal charter
Would you really want to put to sea on a boat
that was owned by someone who was far more casual than The Big Lebowski? Or swap your boat with them?
But you can always pitch
your idea to AirBnB, they might want to carry the business.