We get waterspouts several times a year on Lake Michigan. We can spot them a long way off and we have time to plan how to avoid them. Or if we couldn't avoid it completely, I would treat it as other high winds, reef the main deeply and drop the jib.
I saw the same sort of thing in Antigua. It would touch the surface for a while and then raise up away from the water for a while. It only went on for about 10 or 15 minutes , but it was scary. Only saw it once in 8 years, so it is rare._____Grant.