They were generally similar to the
C-class and
D-class submarines built by
Electric Boat, but larger at submerged vs. for the D class. They were single-hulled boats with circular sections laid along the longitudinal axis.
Overall length was and the
beam was . The
E-class and the F-class submarines were the first US submarines to have
bow planes. Like the E class, their early-model
diesels had problems and were replaced in 1915. The hull contained three compartments separated by partial strength
watertight bulkheads: •
torpedo room with four
18 inch (450 mm) torpedo tubes, •
control room/battery rooms with the
ballast control valves,
hydroplane controls and
periscope. Two
battery wells with 60 cells each were located under the deck in the forward and aft ends of the compartment. •
engine room with two diesel engines The two diesel engines were
clutched to shafts that turned
electric motors that could also be used as
generators for charging the batteries. The shafts also turned the
screws. For submerged operation, the diesels were de-clutched and shut down, with the battery providing all of the submarine's power. The batteries were an array of two sets of 60 cells in rubber-lined, open-topped, steel jars. The small
conning tower fairwater (also known as a
sail) initially precluded any sort of
bridge structure for surface cruising. For extended surface runs, a temporary piping-and-canvas structure was erected to give the topside watchstanders some protection from the elements. The considerable time required to dismantle that structure made
crash diving the boat impossible, and that impediment remained until the introduction of permanent metal "chariot-style" bridge structures in 1917–1919. However, as the F-class served in the
Pacific, they did not receive this upgrade. The streamlined, rotating torpedo tube muzzle cap eliminated the drag that muzzle holes would otherwise cause. In the stowed position, the submarine appears to have no torpedo tubes, as the holes in the cap are covered by the bow stem. With the exception of the
L-class and the one-off , this feature remained standard for submarines designed by the Electric Boat Company, through the
O-class, after which it was replaced with individual muzzle doors faired with shutters that remain standard through the modern day. ==History==