Maybe you should try to find a good and safe harbour to live in first, because I have never heard of people living in houseboats down here?! (Luperon maybe?!)
I am also not sure were to buy a sailingboat in RD- So I would reather buy a sailingboat in Florida if i was you, and just sail down here. There is alot of very nice boats in the US, i hope you find something you like. Good luck!