The L-class boats designed by Electric Boat (L-1 to L-4 and L-9 to L-11) were built to slightly different specifications from the other L boats, which were designed by Lake Torpedo Boat, and are sometimes considered a separate class. The Electric Boat submarines had a length of 168feet overall, a beam of 17feet and a mean draft of 13feet. They displaced 450LT on the surface and 548LT submerged. The L-class submarines had a crew of 28 officers and enlisted men. They had a diving depth of 200feet.[1]
For surface running, the Electric Boat submarines were powered by two 4500NaN0 diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 170hp electric motor. They could reach 14kn on the surface and underwater. On the surface, the boats had a range of 5150nmi at [1] and 150nmi at submerged.[2]
The boats were armed with four 18-inch (450 mm) torpedo tubes in the bow. They carried four reloads, for a total of eight torpedoes. The Electric Boat submarines were initially not fitted with a deck gun; a single 3"/50 caliber gun on a disappearing mount was added during the war.[2]
L-9s keel was laid down on 2 November 1914 by Fore River Shipbuilding Company in Quincy, Massachusetts. She was launched on 27 October 1915 sponsored by Miss Heather Pattison Baxter, and commissioned on 4 August 1916. Assigned to the Atlantic Submarine flotilla, L-9 operated along the Atlantic coast until April 1917 developing new techniques of undersea warfare.
Following the United States's entry into World War I, submarines were needed to protect Allied shipping lanes to Europe. After an extensive overhaul, preparing her for the task ahead, L-9 departed Portsmouth, Virginia, on 17 January 1918 and arrived Bantry Bay, Ireland, on 21 February. She remained in British waters throughout the war, patrolling for U-boats.
After the Armistice with Germany on 11 November, L-9 operated out of the Isle of Portland, England, until she sailed 3 January 1919 for the United States. Arriving Philadelphia, Pennsylvania, on 1 February, the submarine operated along the Atlantic coast for the next four years developing submarine warfare tactics. L-9 decommissioned at Hampton Roads, Virginia, on 4 May 1923 and was scrapped on 28 November 1933.