We were sailing east/west, parallel to Presque Isle State Park and watched an enormous Beneteau coming from quite a distance away, full sails on a north/south heading. We were trying to figure what their intentions were as we were perhaps 1/2 mile off the shore that they were headed directly at. There was no one at the helm or in the cockpit to see they were about to pile up on a beach. As we passed astern I used our air horn to get someone's attention. An older man popped up through the main hatch and looked at us like we were crazy then looked forward at the rapidly approaching beach. It must have been quite the "awww shit!" moment because three more people came flying out and the main sail just dropped like a stone to the deck, the Genoa started to flog so they must have flipped up all the stoppers and uncleated everything. The boat stopped shy of the beach and just sat there for several minutes, not sure what was happening but I bet someone was getting their butt chewed. Might be they were stopped by the keel in the sandy bottom. Eventually the sails were put away and we saw them motoring for the channel and bay.