# United States F-class submarine

The F-class submarines were a group of four submarines designed for the United States Navy by Electric Boat in 1909. F-1 and F-2 were built by Union Iron Works in San Francisco, while F-3 and F-4 were built by The Moran Company in Seattle, Washington.

## Design

They were generally similar to the C-class and D-class submarines built by Electric Boat, but larger at 400 tons submerged vs. 337 tons for the D class. They were single-hulled boats with circular sections laid along the longitudinal axis. Overall length was 142 feet 6 inches (43.43 m) and the beam was 15 feet 5 inches (4.70 m). 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 battery was an array of 120 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 M-1, 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

All four F-class submarines spent their careers in the Pacific Fleet, primarily based in San Pedro Submarine Base , San Pedro, Los Angeles, California with a stint in Hawaii. F-4 was lost off Hawaii on 25 March 1915 due to a battery acid leak corroding the hull. F-1 and F-3 collided off San Diego on 17 December 1917, and F-1 was lost. F-2 and F-3 survived to be decommissioned and scrapped in 1922 to comply with the limits of the Washington Naval Treaty.

## Boats in class

* F-1 (originally named Carp, but renamed F-1 on 17 November 1911) was laid down on 23 August 1909, launched on 6 September 1911 and was commissioned on 19 June 1912. Sunk by collision with F-3 off San Diego, 17 December 1917.
* F-2 (originally named Barracuda, but renamed F-2 on 17 November 1911) was laid down on 23 August 1909, launched on 19 March 1912 and was commissioned on 25 June 1912. Reclassified as SS-21 on 17 July 1920, the submarine was decommissioned on 16 March 1922 and sold afterwards.
* F-3 (originally named Pickerel, but renamed F-3 on 17 November 1911) was laid down on 17 August 1909, launched on 6 January 1912 and was commissioned on 5 August 1912. Reclassified as SS-22 on 17 July 1920, the submarine was decommissioned on 15 March 1922 and sold afterwards.
* F-4 (originally named Skate, but renamed F-4 on 17 November 1911) was laid down on 21 August 1909, launched on 6 January 1912 and was commissioned on 3 May 1913. Foundered off Hawaii, 25 March 1915 due to a battery acid leak.