To the Atlantic side are the Gatun locks. This photograph shows four submarine chasers in the Gatun locks in 1919.
The chaser in the foreground, marked A-6, is the one shown in the photo at the submarine base at Coco Solo. Note the biminis fore and aft, to help shelter the crewmen from the sun.
Photograph of chasers at Gatun locks. Collection of William B. May. Thanks to Penny Thompson, his daughter, for submitting the photo scan.