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HMA 1 "The Mayfly"

Following in the footsteps of Count Zeppelin and the success of his early rigid airships, in 1908 the British Government agreed a sum of £35,000 which "should be allocated to the Admiralty for the building of a dirigible balloon".

This order to build the first British rigid airship was a direct attempt to compete with the German airship programme.

Length 512ft
Diameter 46ft
Speed 42mph (anticipated)
Engines 2 x 180hp
Volume 663, 518cft

Designs were already being submitted and on 7th May, 1909 the award was given to the Vickers company. The original contract had been for a ship to be constructed for £35,000, however Vickers advised that they could construct the ship for £28,000 without goldbeaters skin gasbags and varnished skin outer cover. The Admiralty would be required to provide contractors for this work. Vickers also asked if they could put up a constructional shed, free of cost to the Crown, so that they may have a ten year monopoly on airship construction as they did with the submarine boat agreement they had with the Crown. On May 7th the contract was awarded, but the 10 year monopoly clause was refused.

By 1910 the British Government had committed themselves to a similar path of air-weapon development to that taken by Germany. It was originally planned that the ship be used for scouting capabilities. The project to build the first ship had begun, and designated "HMA No. 1" or more commonly known as "The Mayfly". The design team was working on something that could match the current Zeppelins of the time. These could fly 100 miles, carry a crew of 26, and get to 5,400 feet with an endurance of twelve and a half hours.

The floating hanger alongside Cavendish Dock, Barrow in Furness
HMA 1 under construction in the shed, notice the ship floating above the water.
Plan of the HMA No1.
Plan of the cabin in the keel
The ship emerging from the Dock to the floating mast.
Diagram of the mooring ropes and winches
The wrecked ship

Design and Concept


The Mayfly was built along similar lines to the very early Zeppelins, but with some major modifications which were remarkable for the time. Her original design intention was to be an aerial scout capable of 40 knots for 24 hours, moorable on water with a ceiling of 1,500 feet, with wireless equipment and comfort for a crew of 20. The design was 66 feet longer than her current German contemporary, the LZ-6, and she had a 50% greater volume. Not only would this have given her a correspondingly greater lift than the LZ-6, but, because the Mayfly was constructed with duralumin and not aluminum (which the Germans would not use for another four years), then further weight savings were achieved.

The engine cars had been hand crafted out of watertight mahogany, each carrying one marine racing engine. Each engine drove a pair of 15 foot diameter wooden propellers, mounted on the outside of the gondolas, rotating at half engine speed.

Work began in 1909 both on the ship and also on the shed, which was originally described as a garage. The shed, designed by Vickers, was built from the wall of Cavendish Dock out to piles driven into the basin floor. Once this was completed in mid-1910, the actual construction of HMA No.1 began. The mooring was to be to a mast, which the British were the first to use as standard equipment.

The Mayfly was the first of the rigid airships to be fitted out with the mooring equipment in the nose of the ship. The design of the ship was quite revolutionary in that it was more streamlined than the contemporary Zeppelins, and even the No. 9, 23 or 23X class which were to follow. The shape gave a 40% head resistance compared to existing Zeppelins. A more streamlined shape was suggested for the Mayfly, but the Admiralty rejected it and it was not until the R80 in 1917/18 that a truly streamlined ship was constructed.

The main delay between design and completion of the ship was due to the delay in completion of the shed. The shed was to be completed in August 1909 and the ship delivered two months later, but in June trouble occurred with driving piles in to the floor of the dock, and caused the shed completion to be delayed until June 1910.

In the spring of 1910 the new crew began training and then moved in to the shed in September of 1910. On February 13th, 1911 the Mayfly made her static trials in the shed. The motors were run and controls operated but outdoor trials could not be completed until the weather moderated. It was not until March that the crew were reported ready for launching the great experimental ship.

A new design of floating mast was erected some 38ft high and a "screen" was erected. The mooring was designed to have a steady pull of some 80 tons, however the maximum pressure the ship exerted on the mast in a wind of 80mph was some 4 tons, and hence a large safety margin has been calculated.

Some details of the ship have come to light following the discovery of the "Handbook for HMA No1" which some of the following details have been taken :-

" crew :- 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 tempreature of the living space was a little above that of the outside air, but as the ship proved quite free from draughs in the keel and the cabin, it was anticipated that with suitable clothing, no trouble would be experienced from the cold."

Training of the Airships Crew :

Joined January 25th 1910
February - At Messrs Short Brothers works, Battersea, receiving the following instruction in working rubber fabric:-

Making joints in sheets on the flat
Making joints in sheets on the curve
Making fabric pipes and joins in curve.
Making model gas bags
Sticking channel fabrics to gas bags

March - Instructions in petrol engines at Barrow. Lectures on parting, running and adjusting 15hp Wolsley motor car engine.

April - Signals. Lectures and instruction in aeronautics and meterology

May - Further experience in workin gas bags and outer cover etc.

When the first calculations on weighing the ship had been made, it was discovered that she was too heavy, and after removal of fixtures weighing some three tons, there was hope that the ship would become airborne.

After more drastic surgery on the ship, she was hauled out of her shed on Monday 22nd May 1911, stern first, by boats attached to her side. She was gradually swung out of Cavendish Dock and attached to a mooring pontoon. Whilst she was at the mast, nine officers remained on board and engine trials were conducted, although these were cut short due to trouble with the radiators.

Mooring Out Trials

On Tuesday May 23rd she withstood winds of 45 mph, and during the two nights she was out on the lake, searchlights were played across her so that her actions could be observed. Those who stayed aboard had quarters in the keel and telephone communication between the cars. The ship would still not rise so it was decided to return her to the shed. It was discovered that whilst in her shed, she floated for some five hours with both gondolas some 4 feet out of the water. During this time the engineers were able to perform trimming trials

During her time in the shed a new system was devised for removing her from the shed. A series of electric winches would be used to ease her out, even against a beam wind.


By 24th September 1911, the decision was mate to mover her out of her hanger for full testing.

However, disaster struck in the form of a sudden forceful beam-side gust causing the ship to lurch, just clearing the shed but laid her on to her beam ends. She righted and was them being pivoted so that her nose would point back out to the dock when there were cracking sounds amidships and she broke in two. She started to rise in an inverted "V" formation but t he crew in the after gondola dived overboard and the stern flew up in to the air.

The Wreckage and aftermath

The wreck was returned to the shed the same day. The Court decided that there was no one to blame of this incident and it would be reasonable to support the story that the squall was to blame. It was of such a force that later ships would have also been severely damaged if they had encountered it under the same tethered circumstances.

The ship was left to rot in her shed, when many decisions and arguments were made in the Admiralty regarding the future of Naval Airship operations. However her brief career had supplied an immense amount of valuable information for British Scientists. She may not have flown but she was not a dead loss.

From the original handbook, it was discovered that the ship was required to undertake a series of trials which are very interesting to see what they had planned for the ship and rigid airships as a whole :-


  • Speed in air 1 engine and 2 engines
    Speed on water 1 engine and 2 engines
    Turning circle advance etc
    Effect of auxillary rudders and hydroplanes
    Locating mine field
    Locating submarines
    Ascertain time and distance traversed in bringing up from full speed ahead
    Lying at bouy
    Moored to ship
    Moored to bouy
    Picking up post
    Determing how best to watch a por, count shipping leaving and entering
    Dines recording charts to be kept
    Vision - trying range at different heights
    Practice fixing positions
    Run along coastlines an note conspicuous objects etc
    Take photo's of anything interesting
    Carry out consumption trials
    Time to rise to 800 ft
    At what angle of depression a gun can be fired from an airship
    What amount of recoil is permissable
    The maximum stress that could be taken up by the structure.
    What gun is recommened for use against hostile airships
    What gun is recommented for use against hostile aeroplanes
    Gun positions in airship to be selected.
    Airship chances against hostile aeroplanes
    What gun should be carried for projecting explosives for blowing up caissions of docks etc.

Related ships: HMA 9, HMA 23, HMA 23 X

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