This was originally the Seaplane hangar on submarine S-1 (SS-105). When the S-1 program was cancelled the Seaplane hangar was salvaged by Charles Momsen, the submarine Commander, for conversion to a rescue Bell.

The diving bell is pictured sitting on the after deck of Falcon (ASR-2) during the early stages of the Squalus (SS-192) salvage operations, 1939, 30 May 1939. This is not the McCann Rescue Chamber, but the Momsen-McCann diving bell.