Taken over by the Admiralty before she had passed any flying tests, the ‘Mayfly’ was brought out on September 24th, 1911, for a trial trip, being towed out from her shed by a tug. When half out from the shed, the envelope was caught by a light cross-wind, and, in spite of the pull from the tug, the great fabric broke in half, nearly drowning the crew, who had to dive in order to get clear of the wreckage. There was considerable similarity in form, though not in performance, between the Mayfly and the pre-war Zeppelin. The former was 510 feet in length, cylindrical in form, with a diameter of 48 feet, and divided into 19 gas-bag compartments. The motive power consisted of two 200 horse-power Wolseley engines. After its failure, the Naval Air Service bought an Astra-Torres airship from France and a Parseval from Germany, both of which proved very useful in the early days of the War, doing patrol work over the Channel before the Blimps came into being. Early in 1915 the ‘Blimp’ or ‘S.S.’ type of coastal airship was evolved in response to the demand for a vessel which could be turned out quickly and in quantities. There was urgent demand, voiced by Lord Fisher, for a type of vessel capable of maintaining anti-submarine patrol off the British coasts, and the first S.S. airships were made by combining a gasbag with the most available type of aeroplane fuselage and engine, and fitting steering gear. The ‘Blimp’ consisted of a B.E. fuselage with engine and geared-down propeller, and seating for pilot and observer, attached to an envelope about 150 feet in length. With a speed of between 35 and 40 miles an hour, the ‘Blimp’ had a cruising capacity of about ten hours; it was fitted with wireless set, camera, machine-gun, and bombs, and for submarine spotting and patrol work generally it proved invaluable, though owing to low engine power and comparatively small size, its uses were restricted to reasonably fair weather. For work farther out at sea and in all weathers, airships known as the coast patrol type, and more commonly as ‘coastals,’ were built, and later the ‘N.S.’ or North Sea type, still larger and more weather-worthy, followed. By the time the last year of the War came, Britain led the world in the design of non-rigid and semi-rigid dirigibles. The ‘S.S.’ or ‘Blimp’ had been improved to a speed of 50 miles an hour, carrying a crew of three, and the endurance record for the type was 18½ hours, while one of them had reached a height of 10,000 feet. The North Sea type of non-rigid was capable of travelling over 20 hours at full speed, or forty hours at cruising speed, and the number of non-rigids belonging to the British Navy exceeded that of any other country.