TAMPA — Billy Ray Morris hovered in the water above his prize, the submerged hull of what may be the Kate Dale, a Civil War blockade runner. “It’s a first for Florida if it’s the Kate Dale,” said Morris, a marine archaeologist who specializes in ship construction and interpretation. And he’s 90 percent sure. Union troops burned the Kate Dale — loaded with cotton and ready to run a federal blockade — along with another boat on Oct. 17, 1863. “She’s badly burnt and she’s exactly where she ought to be,” Morris said of the crumbling wooden frame. “Nobody else has found a blockade runner in Florida.” The boat was probably 80 to 100 feet, Morris said. Its buried ruins stretch out 38 feet now, starting about 5 feet from Janet Stanley’s dock. “There has always been this skeleton of a boat, and it’s been whittling down over the years,” said Stanley, who has lived on the river across from Lowry Park Zoo for 10 years. Low tide exposes nubs of the boat’s hull. The underwater excavation is part of a larger project being carried out by Florida Aquarium volunteer divers through a $50,000 state grant. Their goal is to find as many wrecks in the area as possible. Using sonar imaging, they’ve found ruins near Egmont Key and MacDill Air Force Base and in the Manatee River. If this is the Kate Dale, their finds will include a blockade runner and the Union blockade ship Narcissus, which Morris said they mapped last year. Construction features will tell the story, such as the size and type of wood and metal fasteners and the boat’s design. On Friday, Morris hopes to be 98 percent sure. When he’s learned all he can, the ruins will be covered over to rest in peace. “If it came out of the water, it would deteriorate 1,000 times faster,” said Morris, who has explored more than 150 shipwrecks, many of them Civil War vessels. Built in Louisiana, the Kate Dale was one of the boats operated by Capt. James McKay, a blockade runner. The divers also had hoped to find McKay’s paddleboat, the Scottish Chief, in the riverbed. But Morris suspects its burnt hull was dragged back down to Tampa Bay and stripped. McKay struck a deal with Union troops that allowed the Kate Dale to come and go through the blockade. “They let him slip through,” said historian Canter Brown Jr. “He had been a prisoner of war, and he made an arrangement that Abraham Lincoln personally signed off on: If he were released, he would come back to Tampa and he would organize his cattlemen association to support the U.S. military takeover in Tampa. “In fact he was a Unionist,” Brown said. McKay shipped cotton to Cuba and brought back rum, medicine, food and other supplies to be sold dockside. When the relationship became too obvious, Union troops were sent to burn his boats as a cover, Brown said. The Union raid began with U.S. gunboats Tahoma and Adela shelling Fort Brook to distract the Rebels while troops landed at Gadsden’s Point in darkness. They marched overland along the river, found McKay’s boats and destroyed them. Now, 145 years later, the Kate Dale may no longer sleep in an unmarked grave. Times researcher John Martin contributed to this report.