I think you probably have to go where the yachts are, walk the docks, hang out in the right bars, meet and talk to people.
I suggest that you definitely talk to the folks at MPT, check their bulletin board. Maybe take a course there and stay in the crew housing. Meet people that are actively working in yachting.
Daywork123.com is a source of mostly temporary yacht jobs, but some are permanent. I know people in the yachting game who say it’s a good source of work.
Tugboat wages in Florida are comparatively low. There is a lot of turnover. There are jobs on tugs under100 tons that don’t even require an MMC. You would be very competitive in that applicant pool. Tugs are also good experience. Much better than you think.
Dredging and marine construction are other areas of good job opportunity.