A hundred years ago, when we operated a crewed charter boat in the BVI, we would never consider a 3 day charter in-season. WAY too much hassle during a hectic charter season, regardless of whether it would fill a void. But.... in the off season we would do day charters, and shorter charters - really anything to keep the cash flowing. Back in our day June was off-season. Now not so much. I would recommend contacting the BVI Charter Yacht Society. https://www.crewedyachtsbvi.com/ They might be able to refer you to a yacht that would fit the bill!