Reasons for Designation
The grain store at Moat Farm, St Mary Hoo has been designated at Grade II for the following principal reasons:
* the frame was originally the roof section of a First World War non-rigid airship shed;
* it is one of only sixteen such buildings designed by Dalacombe Marechal & Hervieu Ltd for the Royal Navy Air Service. It is not known if any other examples survive;
* one of very few surviving World War I airship hangars, in this case it is likely to have come from the Kingsnorth Royal Navy Airship Station, the main naval airship station in the country;
* the wooden frame survives well including RNAS/Admiralty numbers stamped on the trusses.
Details
ST MARY HOO
1797/0/10027 MOAT FARM ROAD
24-FEB-09 (North side)
Former airship shed at Moat Farm
II
Former balloon shed of World War I date, moved to its current location post 1920 and used as a grain store. Mid and late C20 alterations.
MATERIALS: timber frame; corrugated metal cladding.
EXTERIOR: Rectangular in plan and oriented north-south. Corrugated cladding and roof materials are all mid-late C20. Additional dormer to allow projecting grain drier also of this period. One large entrance to south. Brick outshut and tank to west. All exterior features are not of special interest.
INTERIOR: Original timber frame of former balloon store roof of a 'hoop' construction. The frame has a triangular apex and collar as well as horizontal and diagonal bracing. RNAS/Admiralty numbers are stamped on the frame and read 'KBIII WH'. Additional supports provided by former electricity poles and the purlins have also been replaced. All additions of this nature are not of special interest. Grain bins with walkway and grain drier of mid-late C20 date along west wall are not of special interest.
HISTORY: Prior to World War I there were a number of different organisations responsible for aviation: aerodromes came under the Royal Flying Corps (established in 1912) whereas two specialist aviation stations, for airships and for seaplanes, were the responsibility of the Royal Naval Air Service (RNAS). Airship stations needed mooring stations, gas generators and balloon sheds and did not need a coastal location whereas the seaplane stations required a waterside site with slipways for launching. There was a RNAS site close to St Mary Hoo at Kingsnorth and this is believed to be the origin of the Moat Farm building.
During World War I naval airships provided air observation of German submarines threatening shipping, including supply convoys, in the North Sea and the Channel. Although Farnborough, Hampshire was the location of the very earliest airship trials, such as the development of the very first Submarine Scout (SS) airship (the construction of the first of which was approved in February 1915), airship No. 2 was rapidly moved to Kingsnorth for its trial flight. Farnborough's station was then abandoned by the Naval Airship Service given the expanding aeroplane squadrons there, and personnel and airships transferred to Kingsnorth which became the airship headquarters. There seems to have been activity at the site in 1914 but the station was not completed until 1915 and was then operational until 1920. Demolition probably took place after circa 1930 when the former airship station site was sold.
This is one of only sixteen such balloon sheds designed and built by the firm of Dalacombe Marechal & Hervieu Ltd for the Navy's early small Submarine Scout non-rigid airships. Although the design was quite complex, the buildings were easy to erect (the company claimed that 40 men could erect one in just 10 hours). Francis (1996, p66 & figure at p68) describes how they were built: 'By clever design, the A-frame trestles were erected first at 12 ft 6 in centres (total length 175 ft). Each one was fitted with a worm-driven winch for raising (or lowering) the roof. The central portion of the roof trusses was assembled on the ground including purlins, rafters and canvas covering [or corrugated metal sheeting if in exposed locations], and was then raised high enough to fit the spandrels at either end. The complete roof section was raised by winches and locked in place with automatic catches. The trestles were braced together with wire ropes and the complete shed was canvas clad.'
The roof section at Moat Farm is unusual in being the length that it is: they were designed to be a total length of 175 ft whereas this one is 215 ft long. Either it was always an unusually long version of the Dalacombe Marechal & Hervieu Ltd shed or its represents an amalgamation of two such buildings with an extra 40 ft added. There were understood to be two sheds at Kingsnorth (although the form of the other is not documented) so this is not an impossibility.
SOURCES:
Francis, P, - British Military Airfield Architecture: From Airships to the Jet Age (1996), particularly pp65-80
Saunders, A & Smith, V - Kent's Defence Heritage, Vol 1, Kent County Council (2001) p101-113
Smith, V, - Front Line Kent, Kent County Council (2001),pp77-82.
REASON FOR DESIGNATION:
The grain store at Moat Farm, St Mary Hoo is listed for the following principal reasons:
* For special historical interest as the roof structure of one of only sixteen non-rigid airship sheds designed by Dalacombe Marechal & Hervieu Ltd for the Royal Navy Air Service. It is not known if any other examples survive;
* one of very few surviving World War I airship hangars; in this case it is likely to have come from the Kingsnorth Royal Navy Airship Station and be the sole surving building from this site;
* although only the roof section survives (it would originally have been much taller) the wooden frame survives well including with RNAS/Admiralty numbers stamped on the trusses.
