The BM-2 variant of the BM torpedo bomber was very similar to the BM-1. 9178 struck off charge on 30 June 1938, but the photo was likely taken much earlier.

Although designated Curtiss Scout, the CS was a scout and torpedo bomber designed by the US Navy's Bureau of Aeronautics. CS became SC in the Navy's post-1923 designation system. Only eight CS-1 and CS-2 aircraft, including A-6504, were built by Curtiss. 75 more SC-1s and SC-2s were built by Martin, and the design evolved into the Martin T3M. By mid-1927, the SC was only still in use with a training unit at NAS Pensacola. Photo by: Leslie Jones / Boston Public Library