When I owned a boat with TMM, many years ago, I would strike the deal with the charterer, then turn it over to TMM. They would manage the money, and take care of the charter, just as if they had booked it themselves. Basically, if you have a boat in charter with TMM, Horizon, or similar companies, they primarily want the charter - it can be booked by their booking agent, an independent like Ed Hamilton, or the owner. Each company may work it a bit differently, but that's the general concept - so it's a pretty "safe" arrangement for the client. All this being said, the larger companies (Moorings/Sunsail, who have a little bit more of a time-share arrangement with their owners, work it differently, I believe. If you are booking a boat from someone who does NOT have it with a charter company, that's a whole different set of risks.