Summary
Type G RNAS seaplane shed, constructed c 1918 at Newhaven Seaplane Station, re-erected at Wimbledon Depot early 1920s.
Reasons for Designation
The former WWI, Type G RNAS seaplane shed at Network Rail Wimbledon Depot is listed at Grade II for the following principal reasons:
*Rarity: one of four surviving and only two near-intact Type G RNAS seaplane sheds, built c 1918, providing tangible, material evidence of this pioneering phase of military aviation;
*Intactness: reconstructed 1920s, to its original dimensions, with a near-intact structure and retaining a proportion of its now rare original asbestos cladding;
*Historic interest: built for Newhaven Marine Operations (Seaplane) Station, one of 26 RNAS seaplane stations in the UK, in this case for anti-submarine patrol duties; reconstructed after it was sold by the RAF in the early 1920s and acquired by London & South Western Railway, coinciding with the expansion and electrification of its suburban lines in the 1920s.
History
The first flight by a British Army plane took place in 1908, and in 1910 a permanent flying school and factory was opened at Larkhill on Salisbury Plain. The separate naval and army services formed before the First World War, namely the Royal Flying Corps (RFC) and The Royal Naval Air Service (RNAS), merged to form the Royal Air Force in 1918 occupying 301 sites by the end of the war, and demanding new and larger buildings to meet developments in aviation. Within the UK twenty-six seaplane stations were built over a relatively short period of time, during WWI, to maintain a ring of coastal-based airborne defences.
Newhaven Marine Operations (Seaplane) Station, E Sussex, (SW Area, 10 [Operations] Group, 75th Wing) was the base for 242 Squadron (Flights 408 and 409), engaged in anti-submarine patrol duties. The Newhaven base came under the control of the Commander-in-Chief, Portsmouth. The station was built on the shingle foreshore, 300 yards (c 280m) E of Newhaven Harbour Mouth, and included two purpose-built seaplane sheds, 180 x 60 ft and 120 x 50 ft, and two slipways for handling and maintaining twelve seaplanes.
The Admiralty Type G seaplane shed is similar to the larger scale Type F seaplane shed built at Royal Naval Air Stations (RNAS) from 1916, and designed to open onto a slipway. Type G sheds were 180 x 60 ft side-opening, steel-framed buildings, clad in asbestos sheeting. They were set out in twelve, 15 ft wide bays with a span of 60 ft, with a 90 ft long lattice girder supporting the main door opening. Trusses were either steel or a composite timber truss similar to that used in the 1916 general service flight shed. Workshops and offices were housed in a lean-to annexe to the rear. Other examples remain at Calshot (listed Grade II*) and Lee-on-Solent, both in Hampshire.
Not all bases had this type of shed and records do not indicate how many Type G sheds were constructed. Many seaplane sheds were demolished or moved after the forces combined to form the Royal Air Force, as technology developed and defence strategy changed. While some were reconstructed at Armament Training Schools and Air Observer Schools, particularly in the 1930s, a few individual sheds, such as the example at Wimbledon, were sold for reuse. This former seaplane shed, constructed at RNAS Newhaven c 1918, is one of only four surviving Type G sheds of this date.
The seaplane shed now at Wimbledon Depot was sold c 1921 at an RAF disposals committee auction, dismantled, and acquired by London & South Western Railway (from 1923 Southern Railways), coinciding with the expansion and electrification of its suburban lines in the 1920s. The Wimbledon depot was set up as part of the scheme. The seaplane shed, including its annexe, was re-erected at Wimbledon Depot in the early 1920s for use as a civil engineering and signal telegraph stores building. It is now owned by Network Rail and leased as storage to a film production company.
Details
MATERIALS: steel frame, on a timber cill or brick plinth, on concrete foundations, clad in asbestos-cement 'Trafford Tiles' (manufactured by Turner and Newall, Trafford Park) and rolled steel sheeting. Steel stanchions.
PLAN AND STRUCTURE: 180 ft x 60 ft shed (80 ft 7 in, including the annexe), originally side-opening, set out in twelve, 15 ft bays, reinforced by external raking steel stanchions on the NE and NW elevations. Lower sections of cladding have been replaced in rolled steel sheeting. Clerestorey windows on the northern, eastern and southern elevations and on the annexe are ten-over-three pane, metal-framed units, one per bay. On the north-west elevation windows are continuous vertically lights. The original entrance on the north-west elevation has been in-filled and two sets of smaller ledge and brace timber doors inserted in the cladding, but the frame, stanchions framing the entrance and superstructure remain in place. There are similar doors in each gable wall. A full-height entrance has been cut through on the south-east elevation. Attached to the south-east elevation is a ten bay, lean-to, single-storey annexe that housed workshops and offices. The 7th bay from the south has been removed where the entrance has been cut through.
Steel truss roof. The south-eastern wall is clad internally in steel sheeting below window height. The doorway to the workshop remains in place. Concrete slab floor with caulked joints.
