To improve navigation along the Tennessee River, the United States Army Corps of Engineers built a two-chambered lock as part of Wilson Dam, allowing ships and barges to pass from the east side of the dam to the west side. The lock had an upper chamber measuring sixty by two hundred ninety-two feet and a lower chamber measuring sixty by three hundred feet, and as vessels moved through the two sections, the chambers slowly filled with water to lift watercraft into the much deeper upper portion of the dam. The double-chambered system could raise ships as much as ninety feet from the lower chamber to the upper. It entered service on March 5, 1926, when the steamer General McPherson and the dredge Kwasind first used it. In 1959, a new single-chamber lock replaced the older two-chamber arrangement. At the time of its installation, it was the largest single-chamber lock in the world, measuring one hundred ten feet by six hundred feet with a maximum lift of one hundred feet, and it remains the largest lock east of the Rocky Mountains. Because of its single-chamber design, ships can pass through in an average of forty-five minutes, including a filling time of twelve minutes. The 1959 lock became the main lock in use, while the original two-chamber lock continued as an auxiliary system.

Photo: Sandra Hughes Tidwell

Photo: Sandra Hughes Tidwell

Muscle Shoals, Alabama · USA