(Detroit Free Press ) -- The Keystone State was in trouble.
Big waves slammed into the wooden steamer's sides as it rocked in the water near Port Austin under the weight of a powerful November storm.
And then it was gone, swallowed up by Lake Huron that day in 1861, claiming the lives of all 33 on board.
The ship's final resting place was a mystery for 150 years.
But today, veteran shipwreck hunter David Trotter, 72, of Canton plans to announce he and his crew found the side-wheel steamer in July at the bottom of Lake Huron - the latest in the nearly 100 vessels Trotter has discovered in more than 35 years of Great Lakes shipwreck hunting.
Trotter - who will announce the discovery on his website, www.shipwreck1.com - said he didn't think he'd ever find the Keystone State.
"My expectations were diminished because there was no reason to think she was this far north and in the middle of the lake," Trotter said.
The ship was among the largest steamers of its time. According to some historians, it might have sunk with its crew while secretly hauling Civil War supplies.
The Keystone State also was notable for helping European immigrants settle in the Midwest during the mid-19th Century, according to maritime historian C. Patrick Labadie. He said its discovery can shed light on ship construction methods of the era and how people used to travel.
"This one stands out," Labadie said. "It's a unique wreck."
The Keystone State was built in Buffalo, N.Y., and launched in 1849, when most shipbuilders didn't use written plans. It was just under 300 feet long and had twin stacks, a walking beam engine and giant paddle wheels on either side that were nearly 40 feet in diameter.
It was the second-largest steamship on the Great Lakes at the time and was among a class known as palace steamers, said maritime historian, author and artist Robert McGreevy.
"The interiors were made to look like the finest hotels. They were quite beautiful inside," he said. "They had leaded glass windows and carved arches and mahogany trim."
Along with posh accommodations for the wealthy, its steerage had plenty of space for immigrant travelers heading from Buffalo to destinations like Chicago or Milwaukee. Records show the boat also had room for 6,000 barrels of freight.
An economic downturn in 1857 sidelined the Keystone State and other similar ships, which were deemed too expensive to operate. Some were scrapped. Railroads had been expanding, offering more ways to travel and move goods.
"But when the Civil War started in 1861, all these ships that were laid up, all of a sudden they were worth a fortune again," McGreevy said. "(The Keystone State) was pulled out of storage in 1861, refurbished and sent to Detroit to pick up a cargo that was already waiting for her."
The Keystone State set out from Detroit, bound for Milwaukee, around Nov. 9, 1861.
Its manifest listed iron hardware, farm implements and barrels of grain. But some believe those words disguised the real cargo: munition or other Civil War supplies.
"It was an emergency shipment," McGreevy said. "It was in November, and usually a ship like this would not make an urgent trip the full length of the Great Lakes that late in the year. ... There was a lot of southern sympathy in Michigan at the start of the Civil War, and there was a real threat of sabotage."
Others are skeptical. Wayne Lusardi, state maritime archaeologist, said it seems unlikely that the ship would have carried munition in a direction away from the conflict at a time when many didn't expect the war to last beyond a few more months.
For several days, no one realized the ship had sunk, Trotter said. Then debris was spotted by another ship and later washed ashore near Lexington.
The ship wasn't carrying any lifeboats, a curious detail that could point to the urgency of its final voyage.
Using a side-scan sonar device on Trotter's 32-foot powerboat - the Obsession Too - he and his team found the shipwreck the weekend after July 4.
The zebra mussel-covered wreck is in nearly 175 feet of water, 25-30 miles northeast of Harrisville. Trotter said the location is 40-50 miles from where the ship was last seen on the surface.
Crew members made 30 dives on the site from July through September.
"The stern is kind of broken up and crumbled. The boilers are in good condition, the engine is in good condition," said diver Marty Lutz, 56, of Warren. "The wheels are both standing. ... It was pretty amazing to see those sitting upright on the bottom like that."
Divers shot video for DVDs that Trotter will sell online and use in presentations as part of his Great Lakes Adventure Series program. Trotter has a surveying company, Undersea Research Associates.
"It's the sense of discovery, the sense of exploration. It's always been a passion of mine to find things that no one has found before," he said.
Still, excitement about the discovery was tinged with disappointment. Divers didn't find any cargo or the gold that was rumored to be on board, Trotter said.
"We still haven't unlocked the key to what her intent was at the time she left Detroit," he said.
Shipwreck experts believe the crew may have jettisoned the cargo in a panicked, desperate attempt to save the doomed ship. McGreevy said the only way to know what the Keystone State contained would be to search the vast area believed to be its final route.
"I think it's going to remain one of the mysteries of the Great Lakes," he said.