The dory I was on flipped going into Crystal rapids on the Colorado. Crystal is one of the most notorious rapids in Grand Canyon due to its huge hole and the rock garden just down stream where you end up if you don't make the rapid. Two people, including the boatman went into the hole, getting Maytagged for a bit before they were spit out. I skirted the edge but got by safely, no thanks to my puny attempts at swimming against that current. Looking down into that hole, though, scared the crap out of me. Fortunately, everybody made it to shore safely, the boat was recovered by an earlier one, and we went on our way with a great story to tell.