Joey Gratton, of Sarasota, Fla., died at the Ryder Trauma Center in Miami, said Roderick Cox, a spokesman for Super Boat International. Racing partner Stephen Page, of Fort Myers, was released from the hospital Saturday.
Gratton's death marks the second fatal accident at the race. On Wednesday, Robert M. Morgan of Sunrise Beach, Mo., and Jeffrey Tillman, of Kaiser, Mo., the throttleman and driver for Big Thunder Marine, died in a crash on the first day of racing.
Gratton and Page were on the final lap of the seven-lap race when their 38-foot Superboat 850-class Skater catamaran rolled over twice at checkpoint 1 of the 6.5-mile course. Page was able to get himself out and was taken to Lower Keys Medical Center in good condition. Gratton had to be pulled out of the water by rescue divers and was airlifted to the hospital.
A memorial for Gratton is being held Saturday afternoon.
"It was the classic rollover type of accident; something we've seen before at turns," John Carbonell, president of Super Boat International, the event's sanctioning body, said Friday. "We're investigating the accident, but preliminarily it appears they may have gone into the turn a bit too fast."
Sustained winds were at about 15 mph, with gusts of 23 mph, at the time of the crash, according to forecasters at the National Weather Service in Key West. Wave heights were about 2 to 3 feet.
Some boaters said they had adjusted their strategies after Wednesday's crash.
"It was a terrible tragedy and everybody had it on their minds," said Randy Scism of Wentzville, Mo., a throttleman for the CMS boat that has the lead in the Superboat Unlimited standings.
Officials are still planning to stage Sunday's final races.
Key West World Championship: http://www.superboat.com