NH 74731
Salvage of USS F-4 (SS-23), April-August 1915. A hard hat diver descending to the sunken submarine. Purportedly photographed 90 feet below the surface via a sealed glass bottomed box. F-4 had sunk on 25 March 1915 off Honolulu, Hawaii, in over 300 feet of water. Courtesy of Donald M. McPherson, 1972. NH 74731