From Active Captain: Francis Bay

"Well protected anchorage with National Park Service moorings. Well protected unless wind/swell from N or W. Controlled access to beach for dinghies."

"Beautiful and protected in N swell. Dinghy trip to shore can be rough with the N. swell. Great snorkeling next to the hill. Perfect view and lovely atmosphere."

"Mooring balls well mantained. Great location - can be rolly in some conditions. Be sure to visit the maho bay campground restaurant while you're in the area."

Looks like Leinster might be a better option if swell is up.