Coastal class

It was necessary to build up what was practically a new industry to prepare fabric with rubber proofing to render it gas-tight for airship envelopes. The various water-proofing companies were called upon for this work, and responded with such enthusiasm that by the end of the war there were about half a dozen firms which had specialized in the making of airship envelopes with extremely good results. The SS airships proved so satisfactory that it was decided in July to recommence work on rigid No. 9, and also to start on the production of a larger type of non-rigid which subsequently became known as the "coastal " class, they being intended for anti-submarine patrols up to a distance of 150 miles from shore. The Coastal class was a ship of larger size and capable of lifting a greater load and of longer endurance than the small S.S. airships. The C.1 or coastal type, used an Astra-Torres envelope and a car made from two Avro fuselages with the tails cut off.

An envelope of the "Astra" type was obtained from a ship which had been built before the war as a Belgian millionaire's air yacht. For these the Astra system of rigging was adopted in order to reduce to a minimum the necessary height of the sheds. The Coastal type has a capacity of 200,000 cubic feet. A suitable car to take four men was constructed and rigged below it. This again proved a satisfactory preliminary experiment and was the beginning of the Coastal type. The envelope had to be re-designed, but the modifications made to the car were comparatively small. Thirty-five of these ships were built during the war. Airships of this type did most of the long distance patrols during the last two years, and were largely employed in convoying ships from beyond the Scilly Isles up the Channel.

The Coastal class of ship was modified in January 1918 to the type known as C* (Coastal Star), which had again a better shaped envelope and slightly better crew accommodation in the car. Ten of an improved (C*) class were built during the war. These ships later carried a crew of five and had an endurance of 12 hours at a full speed of 51 knots. The motive power is provided by a 110 h. p. Berliot forward, and a 260 h.p. Fiat aft.

To house these airships the building of new stations was commenced in the Autumn at Longside near Aberdeen, East Fortune on the Firth of Forth, Howden on the Humber, Pulham in Norfolk, Mullion in South Cornwall, and Pembroke in South Wales. These, with the SS airship station), already commissioned, provided a chain of bases all around the coast, distant in the majority of cases only some 100 miles apart. The greatest possible credit is due to Brig. Gen. Masterman, who was personally responsible for the location of these stations, which, although at that time the methods of employing airships in anti-submarine operations were all a matter of pure conjecture, proved later on to be without exception admirably placed for dealing with the very extended activities of German submarines as these were developed in 1917 and 1918.