Lake Michigan shipwreck

A lone paddle-boarder skims Lake Michigan Tuesday, Aug. 8, 2017, in Lake Michigan near Cedar Grove, Wis., passing over the remains of The Atlanta, a passenger and freight steamer sunk there in 1906 with the loss of one life.

Tamara Thomsen, maritime archaeologist, Wisconsin Historical Society, enters the water for a dive Wednesday, Aug. 9, 2017, in Lake Michigan near Port Washington, Wis.

Tamara Thomsen, maritime archaeologist, Wisconsin Historical Society, dives Wednesday, Aug. 9, 2017, in Lake Michigan near Port Washington, Wis. She is heading a crew of divers surveying the underwater site of the J.M. Allmendinger, sunk in 1895 while carrying a load of lumber.

Maritime archaeologists and volunteers from the Wisconsin Historical Society survey in Lake Michigan near Port Washington, Wis. Wednesday, Aug. 9, 2017, at the underwater site of the J.M. Allmendinger, sunk in 1895 while carrying a load of lumber. The site and dozens of other shipwrecks would be protected under a proposed national marine sanctuary for Lake Michigan.

Tori Kiefer, maritime archaeologist, Wisconsin Historical Society, dives Lake Michigan near Port Washington, Wis. Wednesday, Aug. 9, 2017 while surveying with a team the underwater site of the J.M. Allmendinger, sunk in 1895 while carrying a load of lumber. The site and dozens of other shipwrecks would be protected under a proposed national marine sanctuary for Lake Michigan.

Shipwreck enthusiast Steve Radovan, of Sheboygan, Wis., stows a sonar transducer on his boat Wednesday, Aug. 9, 2017 in Lake Michigan. An avid underwater explorer since the mid-1970’s and discoverer of sunken ships, Radovan is a strong advocate for a proposed national marine sanctuary for Lake Michigan.

The hull of the Lottie Cooper, a ship sunk off Sheboygan, Wis. in 1894, is preserved in a park in Sheboygan and shown here on Wednesday, Aug. 9, 2017.

The hull of the Lottie Cooper, a ship sunk off Sheboygan, Wis. in 1894, is preserved in a park in Sheboygan and shown here on Wednesday, Aug. 9, 2017.

An antique gauge from the Roscinco, sunk off Kenosha in 1928, in the home Wednesday, Aug. 9, 2017, of shipwreck enthusiast Steve Radovan, of Sheboygan, Wis. He legally acquired it and other artifacts during his exploring of Lake Michigan shipwrecks. An avid underwater explorer since the mid-1970’s and discoverer of lost, sunken ships, Radovan is a strong advocate for a proposed national marine sanctuary for Lake Michigan. (Chris Walker/Chicago Tribune)