I don't want to discourage you from your quest, Kathryn and John (and Luca), but at this time of year most pleasure yachts are returning north, not heading south. Most private yachts carry insurance
that is void if the yacht is south of (generally) Cape Hatteras after June 1 and before December 1 (policies differ - the line could be further north or south and the dates can vary). The reason, as I'm sure you already know, is hurricane
At this time of year, most pleasure yachts are cruising northward to enjoy the summer months off New England
. But most have already gotten to those cruising grounds by now.
If your hearts are set on finding an opportunity in the islands at this time of year, I'm not saying it's impossible - it's just not as common. It's understandable that a teacher's schedule only allows a summertime window of opportunity, and the islands can be wonderful then, but most cruisers will have long-since departed northward, or retreated south of about 12.5* north latitude (out of the hurricane
belt on the southern side.)
Good luck in your quest.