During World War II, the Wisconsin Based Manitowoc Ship Building Company constructed twenty eight Gato/Bolao Class submarines, bolstering the production of existing Naval Shipyards. The completed submarines traveled from Lake Michigan down the Illinois River system, passing this point. Because some river channels were only seven feet deep, the boats were transported from Lockport in a special floating dry dock, and their masts were removed to clear bridges. After reaching New Orleans, they were free to cross the Pacific Ocean and join the fight. Four Manitowoc submarines, Golet, Kete, Lagarto and Robalo, along with 336 officers and enlisted men, were lost during the war.