On 25 November 1911, at Windermere, Waterbird made the world’s first successful flight to use a ‘stepped’ float, only achieved by embodying Edward Wakefield‘s two years of persistent experiments. The pilot was Herbert Stanley Adams. This telegram confirms the initial flights.
Gertrude Bacon, who flew as a passenger in Waterhen and the Deperdussin at Windermere during 1912, explained the step in her book All About Flying: ‘the lower surface of the float, instead of being all of one piece, changes or ‘steps’ abruptly to another level. Some floats have one step, some more’. The two steps on Waterbird’s float may be appreciated on the photo opposite, taken at a time before the hangar floor at Hill of Oaks had been constructed.
The history is here
‘It was a clergyman, the Rev. C. M. Ramus, who first suggested the hydroplane, in 1872, and he drew the attention of the Lords of the Admiralty to his experiments and their results [for warships] but the scheme as a whole was abandoned.’ – Flight magazine, 22 February 1913. The work by the Reverend Ramus ‘became generally known again in 1908 when it was republished in the Motor Boat magazine’. – Pioneer Aircraft: Early Aviation before 1914 by Philip Jarrett. ‘So far as one can gather, the patent, which was taken out in 1906 by Albert Edward Knight, is the first patent on record relating to “stepped” hydroplanes’ [for boats]. – The Aeroplane magazine, 4 September 1913.
On 28 March 1910, Henri Fabre made the first flight from water, near Marseilles. However, his float was not stepped but was arranged with the flat part underneath, with a curved upper surface, so as to generate lifting force when moving on water or in air.
Glenn Curtiss flew from water on 26 January 1911, at San Diego Bay, California. Waterbird’s float was of a Glenn Curtiss-type, but the Curtiss float had been designed to ride through waves of the sea, shaped so that it would tend to rise on the surface and was flat-bottomed, not stepped.
On 11 December 1911, through agents Arthur Edwards & Co., Wakefield filed Patents No. 27,770 and No. 27,771 relating to the means for float attachment including rubber bungees to provide shock absorption when taking off and alighting, and a stepped float, which were respectively granted on 12 September 1912 and 18 March 1913. The object of the invention was ‘to provide an aeroplane with means for enabling it to alight, float and travel along the surface of water and to rise again therefrom’. Wakefield had thus combined features of construction in a novel way.
Wakefield also had inflatable balancers fitted beneath each wing tip, which came to be known locally as ‘Wakefield Sausages‘. – Britain’s Seaplane Pioneers, by M H Goodall, Air Pictorial December 1987.
Further, on 13 November 1913, Wakefield obtained Patent No. 18,051 for a float of a seaplane to support its own weight or the greater part of such weight during flight.
The development of Waterbird’s float, as depicted in the video clip below, was: built in May 1911, with the additions of a single step in September, a second step towards the stern in November, and a tapering stern later.
‘The hydroplane float is 12 feet long by 2 feet wide by 1 foot deep, the sides are of ¼” mahogany, the bottom of 22 gauge aluminium and the top covering of Willesden waterproof canvas. Wooden lattice girder frames are fitted internally 8″ apart to stiffen up the float and a centre longitudinal of wood runs centrally from bow to stern inside. Wood beading is used at the corners inside to ensure watertightness. No watertight compartments are at present fitted but Mr Wakefield says he can fit seven with about 15lbs extra weight. The weight of the float is about 96lbs, but with a new one under construction should weigh only 70, this latter has a duralumin bottom on which the sea has no bad effect. Two steps occur in the bottom of the hydroplane, one at about half way of 4″ and the other 8″ from the stern of 3½”. The float is attached to the machine by a rubber spring 3 point suspension, the struts being of steel tubing.’ – Report by Lieutenant Arthur Longmore, who test-flew Waterbird for the Admiralty on 20 January 1912.
The original Waterbird float has survived and is at the RAF Museum Reserve Collection.
On 14 March 1912, Wakefield entered into a contract with the Admiralty for floats and undercarriages, or royalties, and to convert Admiralty Deperdussin M1 (a monoplane) into a hydro-aeroplane, which he achieved within four weeks from delivery.
In a move away from the flat bottom of initial floats, which gives a faster take-off, designers developed the wave-cutting, spray-deflecting, V-shaped float bottom which is used on almost every float today. On 12 February 1914, Gnosspelius obtained Patent No.10,801 for a V shaped construction.
The following are examples which used steps:
Supermarine S.6B racing seaplane, Boeing 314 Clipper flying boat, Consolidated Catalina flying boat, Slingsby Falcon glider flown from Windermere in 1943 by Cooper Pattinson and Wavell Wakefield and Tiger Moth.
In early Short Sunderland flying boats the hull step was an abrupt one, but in the Mark III it was a curve upwards from the forward hull line. The Mark III was the definitive Sunderland variant with 461 built, which included 35 at White Cross Bay, Windermere between 1942 and 1944.