Shipwreck hunters plumbing Lake Huron say they found the Keystone State, lost for 152 years after it sank in a powerful November storm. Veteran shipwreck hunter David Trotter, 72, of Canton said he and his crew found the sidewheel steamer in July at the bottom of Lake Huron northeast of Harrisville, about 50 miles from where the vessel was last seen, the Detroit Free Press reported Monday. Trotter said he and his team found the zebra mussel-covered wreck the weekend after Independence Day using a side-scan sonar device on Trotter's 32-foot powerboat. "The stern is kind of broken up and crumbled. The boilers are in good condition, the engine is in good condition," diver Marty Lutz said. "The wheels are both standing. ... It was pretty amazing to see those sitting upright on the bottom like that." Trotter said divers found no cargo or gold 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" for Milwaukee around Nov. 9, 1861, he said. Built in Buffalo, N.Y., and launched in 1849, it was the second-largest steamship on the Great Lakes at the time and was among a class known as palace steamers, maritime historian, author and artist Robert McGreevy told the Free Press. Some historians say the Keystone State -- instrumental in bringing immigrants to the Midwest -- may have sunk while secretly hauling Civil War supplies. Others question the veracity of that scenario.