DETROIT - The crew of the WingNuts knew trouble was brewing in northern Lake Michigan.

As lightning bolts erupted from a midnight sky and gusts kicked up churning waves, the eight people aboard the 35-foot sailboat dropped their main sail and clipped on safety lines. Their vessel, among hundreds taking part in the annual race from Chicago to Mackinac Island, was near North Fox Island off the northwest Michigan coast when disaster struck.

A gust estimated at 75 mph hammered WingNuts, flipping it over. The capsized boat heaved up and down in 4- to -6-foot waves as six members of the crew managed to cut or unclip their lines, cling to the hull and signal for help.

But their beloved skipper, Mark Morley, and crew member Suzanne Bickel could not free themselves. A Charlevoix County dive team found them dead about eight hours after the survivors were rescued by Sociable, a competing ship.

"The WingNuts crew is indebted to the crew of the Sociable and are heartbroken over the loss of their crew members, Mark and Suzanne," the survivors said in a statement that described the accident.

The deaths are the first caused by the weather or an accident in the race's 103-year history, although one sailor died years ago of a heart attack, said Rachelle Treiber, spokeswoman for the Chicago Yacht Club, which organizes the event.

Morley, 51, and Bickel, 40, were boat racing veterans. Morley had participated in six Chicago-Mackinac races and Bickel had taken part in two, the yacht club said.

Despite their experience and preparation, the storm was too sudden and powerful.

"It was among the nastiest, if not the nastiest, that I've seen," said Adam Hollerbach, 33, of Detroit, who sailed aboard the 70-foot vessel Details. He said his boat reached Mackinac Island's harbor just as the storm unleashed its fury, with wildly shifting gusts, lightning bolts and stinging hail.

On the open lake, the WingNuts team bore the brunt.

"They knew it was coming but it just sort of caught the boat the wrong way," said Chip Cummings of Rockford, whose 16-year-old son, C.J., was among the survivors.

WingNuts is based in Saginaw, and seven of the eight crew members were from Michigan. The other was from Chicago, where the race started at Navy Pier for some competitors on Friday but for most on Saturday.

The vessel overturned about 13 miles northwest of Charlevoix and about 270 miles from Chicago. Air and water temperatures early Monday were in the low 70s. The occupants wore life preservers, the Coast Guard said.

Cummings told The Associated Press his son, a cousin of Mark Morley, and other crewmates pressed devices on their vests, alerting the Coast Guard that they were in peril.

Cummings said Stuart Morley, 15, Mark Morley's nephew, was able to undo the harness that was attaching him and the other sailors to the boat, then released C.J.'s harness. That enabled both of them to clamber onto the hull.

Sociable rushed to the scene, radioing other competing crews. Ten boats dropped from the race to aid the search as Sociable plucked five of the stranded sailors from harm's way and shortly afterward rescued a sixth.

Cummings said his son, who lives in Grandville, was exhausted but otherwise physically fine. The other rescued sailors were Mark's brother Peter Morley, 47; John Dent, 50; Stan Dent, 51; and Lee Purcell, 46.

A 41-foot utility boat from the Coast Guard station in Charlevoix arrived. Crew members knocked on the hull to see if anyone was trapped inside. Hearing no response, they began a broader search. Mark Morley and Bickel eventually were found close to the vessel.

Organizers say 355 boats and roughly 3,500 crew members took part in the race, which finishes off Mackinac Island in the straits where Lakes Michigan and Huron meet. The first race was in 1898, and organizers began holding it every year starting in 1921.

Morley loved it, those who knew him said.

"Mark lived to sail - he lived and breathed sailing," Chip Cummings said. "He was certainly the most accomplished sailor ... I've ever met."

Grant Hilger, who sailed with Morley previously but was with a different crew for this race, said he was a member of a sailing family and took pleasure in repairing and restoring boats. On the water, he was "a big storyteller, had stories that went on and on," Hilger said.

Bickel, also a veteran sailor and scuba diver, sailed on the Atlantic Ocean and Mediterranean Sea as well as the Great Lakes, the crew's statement said.

Participants in some past Chicago to Mackinac races have dealt with severe weather, according to the race's website. An 80-mile gale in 1911 caused the vessel Vendector to crash on rocks near Fisherman's Island off Charlevoix. The crew survived.

A crewman was swept overboard during a 65-mph gale in 1937 and rescued by the Coast Guard. Just eight of 42 yachts were able to finish the race that year.

In 1970, a storm caused 88 of 167 starters to withdraw. A gale in 2002 capsized the 44-foot Caliente and damaged other vessels

Racers were in a somber mood as they arrived at Mackinac Island and learned of the WingNuts' fate, Hollerbach said.

"You know that it could have been you," he said.

Flesher reported from Traverse City. AP researcher Monika Mathur contributed to this report.