Bluebird K7
At the start of the second run, Bluebird was going faster than 320 mph (510 km/h) and would have easily broken the 300 mph target, but as the boat travelled along the lake it started tramping (which means rocking from side to side). Bluebird hit a wave made on the lake from its own first run and the boat spun out of the water.  When it hit the water again it broke into pieces and sank.  Donald Campbell was killed in the crash.  His teddy bear mascot was found floating in the lake later on but Campbell's body could not be found.