Apparently this video is from a sprintboat race. As far as I can tell a sprintboat race consists of going really fast around a tight water coarse and hoping you don't crash and die. There is a driver and a navigator on the boat and each boat has a roll bar. The water channels that the boats go through are very thin and if you don't make a turn you eat it in the dirt with your boat. Well this video is pretty long and shows a whole bunch of different boats doing various crashs on the sides of the narrow water coarse. There is also a camera clip of one boat successfully completing the coarse. If you watch the video you can see the navigator guy moving his hand to tell the driver which way to turn.