C.23 Coastal Class airship served the British Royal Navy during World War 1 (1914-1918). The aircraft was constructed in 1916 and began operational service in 1917, completed with a compound tubular shape. It was defined as a "non-rigid" airship which described it as lacking any rigid understructure to hold the general shape of its envelope (unlike the better known German Zeppelins in use). The design, instead, utilized a high pressure gas within the envelope to fill out the shape. Fins were added to the sides and under the tail design and power derived from a pair of engines - a Sunbeam brand installation of 150 horsepower and a Renault engine of 220 horsepower. One engine was fitted at the front of the suspended gondola and the other found at the rear to provide a complete "puller/pusher" configuration. The piloting/observation/gunnery crew resided at the gondola which featured five open-air cockpits inline. The pilot sat in the central position while a trainable Lewis machine gun position was at the rear-most position. The gondola was a simple fusing of two Avro 504 aircraft fuselage units with the engines installed at each end. The structure also carried 4 x 112lb bombs or 2 x 230lb bombs along its underside to conduct bombing sorties. Naval depth charges could also be substituted. To go along with the rear-set Lewis machine gun placement, there was another dorsal-mounted Lewis machine gun emplacement reachable by rope ladder from the gondola. The gondola was further fitted with landing skids for when not airborne. In all, the C.23 measured a running length of 200 feet.
Airships provided good, cost-effective reconnaissance tools for all sides during The Great War. The aircraft were able to travel great distances and at high altitudes, usually out of the range of early interceptors and ground-based fire. Their tactical value was doubled in that these vehicles could traverse over land or water with equal ease, proving them valuable to both army and naval forces alike. Coastal airships, as their name would suggest, were primarily utilized in the maritime patrol role and, for the Royal Navy, this meant searching, tracking and engagement of German submarines threatening the merchant fleet. Without logistical and material support, the island nation could be starved into submission and removed from the war. As such, the C.23 was used in the anti-submarine role for her time in service.
C.23 managed a relatively short operational existence until May 1st, 1917 when its Lewis machine gunner accidentally struck the envelope which forced the aircraft to collapse. The vessel was officially removed from active service on May 11th, 1917. The Coastal Class numbered 27 in all and many were scrapped during 1919 following the cessation of hostilities. In all, the Royal Navy held in its wartime inventory some 213 airships.