Salvage of USS F-4 (SS-23), April-August 1915
Salvage pontoons on the surface, off Honolulu, Hawaii, circa 29 August 1915, after the final lifting of the sunken submarine in preparation for towing her into Honolulu harbor. Note wooden protective sheathing around the pontoons. Salvage equipment was devised by Naval Constructor Julius A. Furer. The tug at right is probably USS Navajo. Courtesy of Donald M. McPherson, 1972. U.S. Naval History and Heritage Command Photograph.