I don't think you will find an economical way to
charter a boat for 6 months. We looked at it from every angle we could, and in the end decided it would still be cheaper to buy a nicer boat and then sell it again after the sabbatical, eating any losses than any sort of rental scheme.
As to
single handing, I suppose if you are young, good looking and somewhere warm, you could do like a lot of YouTubers and take on equally good looking crew and make a career of it. ;-) Seriously though, it might come down to where you want to
cruise. There are a lot of people in a lot of places who want to go cruising for free. Or, I suppose, you could be one of them yourself, and bum rides on other peoples boats, offering up your services for deliveries etc. although that
route is difficult to guarantee success.
My
advice? Figure out where you want to be, then figure out how you will get a boat, and then
work on acquiring crew. Then go back to the beginning and see how it works in another location. I believe you will find that the scenarios for cruising in the
Med will be completely different than the ones for cruising in the
PNW etc. At least it was for us...