This image is of a steamship waiting to progress through the Soo Locks between Lake Superior and Lake Huron. This particular lock is currently unused pending replacement with a much larger lock once funding is secured.
Genuine Curteich-Chicago “C.T. Art Colortone”
There is no additional description on the back of this card, but the steamship pictured here is named after James A. Farrell, the former president of the U.S. Steel Co.
The postcard was used and is dated June, 1939.