I'll post it to youtube some day, so the meteorologists can pick at it. It was a small, rapidly moving patch of dark water on the already dark water. You can see it run into the boat from windward and WHUMP! within a second everything up was down...
Even with steady tradewinds, we do get some crazy wind events around the marine base. Often holes and sharp 90º shifts, even jet wash! There's also an area I call the Hawaiian Triangle, where the channel tides and winds converge to put everything on pause, just as you're trying to get over a big reef/marker.
It may just be the Navy testing its new Anti-Catamaran weapon system.