The L-class boats were enlarged and improved versions of the preceding E class. The submarine had a length of 231feet overall, a beam of 23feet and a mean draught of 13feet. They displaced 891LT on the surface and 1074LT submerged. The L-class submarines had a crew of 35 officers and ratings.[1]
For surface running, the boats were powered by two 12-cylinder Vickers[2] 12000NaN0 diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 6000NaN0 electric motor.[1] They could reach 17kn on the surface and underwater.[3] On the surface, the L class had a range of 3200nmi at .[1]
The boats were armed with a total of six 18inches torpedo tubes. Four of these were in the bow and the remaining pair in broadside mounts. They carried 10 reload torpedoes, all for the bow tubes.[4] L2 was initially fitted with a 3adj=onNaNadj=on anti-aircraft gun, but this was later replaced by a 4adj=onNaNadj=on deck gun.[5]
Originally laid down as E-class submarine E58 on 18 May 1916, she and sister ship incorporated enough changes that they were renamed as the first pair of boats of a newly designated L class. L2 was launched 6 July 1917, and commissioned on 18 December 1917.
During World War I, L2 was on patrol when she became the target of a friendly fire incident involving three United States Navy destroyers. On 24 February 1918, the destroyers,, and were proceeding in a scouting line in the Atlantic Ocean off the south coast of Ireland bound for Queenstown, Ireland, when Paulding sighted L2′s periscope. Mistaking L2 for an Imperial German Navy U-boat, Paulding headed for the periscope at flank speed and opened gunfire. L2 had sighted the destroyers and, assuming that the destroyers had not seen her periscope, submerged to 90feet, but upon hearing Paulding open fire, she dove to 200feet. Paulding dropped two depth charges, the first of which shook L2 severely and jammed her diving planes in a hard-upward position. This caused L2 to take on a tremendous inclination, and her stern struck the seabed at a depth of 300feet. Four more depth charges exploded, again shaking the submarine. Her commanding officer, Lieutenant Commander Anworth, gave the order to blow the number 5 and 6 ballast tanks, and L2 surfaced bow-first. Davis dropped a depth charge near her, and then all three destroyers opened gunfire on her from a range of about 1500yd. One round struck L2′s pressure hull just abaft her conning tower. Some of L2s crew emerged from her conning tower, waved their hands and a White Ensign, and fired a smoke grenade. The destroyers ceased fire immediately. L-2 did not sustain serious damage, and Davis escorted her to Berehaven, Ireland.[6] The force commander of British submarines, Captain Martin Dunbar-Nasmith, commended L2 and the destroyers for the action in his report on the incident. Admiral Lewis Bayly, the Royal Navy′s Commander-in-Chief, Coast of Ireland, in his endorsement of Nasmith′s report, wrote, "Had L-2 not been very skillfully and coolly handled, she would have been lost. The U. S. destroyers deserve great credit for their smartness in attack, and for their quickness in recognizing the submarine as British."[6]
L2 was assigned to the 4th Submarine Flotilla and in 1919 and proceeded to Hong Kong, arriving on 14 April 1920, She was placed in the Reserve Flotilla in Hong Kong in 1923. She was sold in March 1930, and arrived in April 1930 at Thos. W. Ward, Grays, Essex, England, for breaking-up.