HMA No. 1 - Construction and Trials

Construction and Trials

The construction shed (which doubled as a hangar) was designed by Vickers and built from the wall of Cavendish Dock at their "Naval Construction Yard" in Barrow, out to piles driven into the basin floor. It contained a float on which construction of the airship took place and which could be taken out of the shed together with the airship. Beginning in 1909, the work was due to be completed in August that year and the ship delivered two months later, but in June trouble occurred with driving the piles into the floor of the dock. Consequently, the shed was not completed until June 1910, at which point the actual construction of HMA No. 1 could begin. A screen was erected in the dock together with a newly designed 38 ft (12 m)-high floating mooring mast that was capable of withstanding a steady pull of 80 tons (70 tonnes). A large safety margin had been allowed – the maximum load the ship would exert on the mast was calculated to be approximately 4 tons (4 tonnes) in a wind of 80 mph (130 km/h).

In preparation for the completion of Mayfly, crew training commenced on 25 February 1910, covering important skills such as working the rubber fabric (carried out at Messrs Short Brothers works, Battersea, London), instructions in petrol engines at Vickers works, signals, instruction in aeronautics and meteorology.

An entry in Handbook for HMA No. 1 noted that:

"Two crews were used to look after the ship whilst out, as the work was new. They lived on board the airship and suffered no discomfort at all although no provision had been made for cooking or smoking on board. At night the temperature of the living space was a little above that of the outside air, but as the ship proved quite free from draughts in the keel and the cabin, it was anticipated that with suitable clothing, no trouble would be experienced from the cold."

The Admiralty's officer responsible for the design of HMA No. 1, Lieutenant N. F. Usborne, was selected as her Captain following the comments made by the Inspecting Captain of Airships, Captain Murray Sueter who said, "Lieutenant Usborne has conducted himself to my entire satisfaction. A very zealous and capable officer, he has worked hard in making himself an expert in aeronautical work. I strongly recommended him for promotion."

Commander Edward Masterman, Officer Commanding, Naval Airship Section wrote, "It is no exaggeration to say that his was the outstanding personality in the project. Nothing was decided without his advice and few things undertaken of which he disapproved. His was the knowledge, slight though it now appears, for undertaking the construction of a rigid airship larger than any existing, it was his brain and his drive which set matters going in the progress of this great experiment. He was the expert and revelled in so being."

Throughout construction the Admiralty expressed their doubts about airships. The constructors modified the design even as it was built in order to meet specifications and when it appeared that the airship would be too heavy removed some of the structure to lighten her. This included the main keel. One of Vickers draughtsmen calculated this would cause her to break up.

The finished Mayfly was the largest airship yet constructed.