United States L-class submarine

The United States L-class submarines were a class of 11 coastal defense submarines built 1914–1917, and were the most modern and capable submarines available to United States Navy when the country entered World War I. Despite being considered a successful design by the USN, war experience in European waters demonstrated that the boats lacked the range, speed, and endurance to conduct extended patrols in the North Atlantic.

Design
These submarines were built to two distinctly different designs at four separate shipyards. The Electric Boat Company (EB) of New York City (later Groton, Connecticut) went the route they followed with previous designs and simply scaled up their standard single hull, spindle shaped, twin propeller, axial rudder design to meet the requirements of the Navy. They were contracted for L-1 through L-4 and L-9 through L-11, and these would be built at EB's sub-contractor Fore River Shipbuilding Co. in Quincy, Massachusetts. For the first time EB did away with the rotating bow cap for the torpedo tube muzzle doors. It was replaced by individual faired-in shutter doors that would later become a standard design feature. Simon Lake's Lake Torpedo Boat Company returned to fold and submitted a very different design that would become L-5 through L-8. These boats were similar in size and capability to the EB design, but they had a ventrally mounted rudder and propeller shafts, a watertight superstructure to aid in surface buoyancy, and different engines and motors. They also had three sets of amidships mounted diving planes, as opposed to EB's standard bow and stern planes. The only one of the four that would actually be built at Lake's Bridgeport, Connecticut yard was L-5. The Navy wanted some of the boats built at a west coast shipyard, so Lake sub-contracted with the Craig Shipbuilding Company of Long Beach, California to build L-6 and L-7. Desirous of creating their own in-house submarine construction capability, the Navy's Bureau of Construction and Repair obtained a license from Lake to build the L-8 at the government owned Portsmouth Navy Yard in Kittery, Maine. L-8 would be the first of many submarines built at government Navy Yards.

As in previous U.S. designs, the conning tower and fairwater was kept small for reduced drag when submerged. For extended surface runs, the fairwater was augmented with a temporary piping-and-canvas structure (see photo) which took considerable time to deploy and dismantle. Experience in World War I showed that this was inadequate in the North Atlantic weather, and these boats, along with other submarines serving overseas in that war (E-class and K-class) had their bridge structures replaced with a permanent steel "chariot" shield on the front of the bridge. Chariot style bridges became standard on later U.S. submarines.

This was the first U.S. submarine class equipped with a deck gun, in this case a 3-inch/23 caliber (76 mm) partially retractable design. The gun was installed on the EB design boats only, the Lake design never received one. The gun was retracted vertically, with a round shield that fit over the top of a well in the superstructure that projected into the pressure hull. Most of the barrel protruded from the deck, resembling a stanchion. The round shield doubled as a blast deflector for the gun crew, and as the watertight top of the well. This gun was roundly disliked by the submarine crews because it lacked range, hitting power, and had the tendency to retract back into the well when fired, presenting a great hazard to the gun crew.

Service
After service in the Atlantic Flotilla by the Electric Boat design submarines, most required extensive refits at Philadelphia after the USA's entry into the First World War, which reflected the U.S. Navy's then-limited experience in submarine ocean operations. In December 1917, the seven boats were sent to Bantry Bay as Submarine Division 5 for convoy escort and anti-U-boat patrols. The four new Lake design L-boats later deployed to the Azores in November 1918 as Division 6 to reinforce four K-class submarines sent there in October 1917. While forward deployed, U.S. L-class submarines had the letter "A" added to the name displayed on the fairwater (i.e. AL-1) to avoid confusion with British L-class submarines.

U.S. submarines did not sink any U-boats in World War I, despite the immense effort of getting them to the war zone. Many lessons were learned and these were poured into the design of follow-on submarines. After the war, the L-class were involved in trials of new torpedoes and hydrophone equipment on both the east and west coasts before decommissioning in 1922 and 1923. At least L-3, L-9, and L-11 were re-engined with Busch-Sulzer diesels removed from Lake-built N-boats in 1921. Three EB design boats were scrapped in 1922, the four Lake design boats were scrapped in 1925, and the remainder were scrapped in 1933 under the London Naval Treaty limiting naval armament.

Boats in class
The 11 submarines of the L class were:

Electric Boat design

Lake Torpedo Boat Company design