During the First World War, the United States Navy trained crews at British bases, and operated British designed and built blimps on combat patrols. The Navy purchased three types of British blimps. Operations were flown in a US SSZ and airships operated by the Royal Navy. SSZ class The US Navy purchased two SSZ class blimps, which were long, in diameter and had a volume of . They were propelled by a single Rolls-Royce Hawk engine. A replacement SSZ-23 was acquired in November 1917 and first operated from Cranwell for training. It was then assigned patrol duties from RNAS Howden. These operations included at least 24 operational missions in the spring of 1918. Ensign Phillip Barnes received the Distinguished Flying Cross from King George V during one of those flights. The SSZ-23 then was transferred to Lowthorpe and completed another 24 operational flights by August, when it returned to Howden where it was destroyed in an accident. While preparing to mate the old SSZ-23 envelope to a spare control car, the US maintenance crew started a fire which burned the SSZ-23, SSZ-38, SSZ-54 as well as the rigid airship R27. A replacement airship, also designated SSZ-23 was acquired on 22 November 1917 and was eventually shipped to the United States and erected at Cape May in early February 1919. Served at Cape May until April of that year and was stricken from the Navy registry in June 1920. The SSZ-24 was assembled and tested by the Navy and Goodyear in March 1918. It was shipped to Hampton Roads. There are no records of any operations at Hampton Roads. The SSZ-24 may have been burned in the summer of 1918. North Sea class The US Navy purchased one North Sea class airship. N.S.14 was sold to the US in early November 1918 after flying 206 hours in British service and the USN designation NS-1. NS-1 was shipped to Wingfoot Lake, and then Hampton Roads, but there is no record it was ever flown while owned by the US Navy. North Sea blimps were long, had a diameter of and a volume of . They had a top speed of , an endurance of 24 hours and were powered by two Rolls-Royce Eagle engines or two Fiat engines. SST class The US Navy purchased three SST (Sea Scout Twin) airships from Britain in 1919. The SST-9, SST-11 and SST-12 were transferred to