The three remaining F-class submarines, most likely at Mare Island for inspection and repair, circa 1916. After the sinking of the F-4 the remaining F-class boats were ordered back to the mainland to be examined and overhauled before they would be permitted to dive again.
The right-hand submarine has had panels removed from both sides of its conning tower fairwater, exposing all the systems within it. She also has a deck plate propped up to access equipment within the superstructure.
The middle and left-hand submarines have had the superstructure removed over their engine mufflers and exhausts for some sort of maintenance.
Photo courtesy of Mike Dilley, whose father, Homer "Pat" Dilley sailed aboard the USS F-2.
