Admiralty scaffolding

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A drawing of Admiralty scaffolding from 1940
A section of Admiralty scaffolding prepared for testing
Extant remains at Salthouse, North Norfolk, England.

Admiralty scaffolding, also known as Obstacle Z.1 or sometimes simply given as beach scaffolding[1] or anti-tank scaffolding,[2] was a British design of anti-tank and anti-boat obstacle made of tubular steel. It was widely deployed on beaches of southern England, eastern England and the south western peninsula during the invasion crisis of 1940-1941.[3][4] Scaffolding was also used, though more sparingly, inland.[5]

Of a number of similar designs, by far the most common was designated obstacle Z.1. This design comprised upright tubes 9 feet (2.7 m) high and 4 feet 10 inches (1.5 m) apart, these were connected by up to four horizontal tubes. Each upright was braced by a pair of diagonal tubes, at about 45°, to the rear.[6] 20-foot (6 m) wide sections were preassembled and then carried to the sea to be placed in position at the half tide mark as an obstacle to boats.[6]

However, trials found that a 250-ton barge at 5 12 knots (6.3 mph; 10.2 km/h) or an 80-ton trawler at 7 12 knots (8.6 mph; 13.9 km/h) would pass through the obstacle as if it were not there and a trawler easily pulled out one bay with an attached wire rope.[7] Tests in October 1940, confirmed that tanks could only break through with difficulty, as a result Z.1 was adopted as an anti-tank barrier for beaches thought suitable for landing tanks. As an anti-tank barrier it was placed at or just above the high water point[6] where it would be difficult for tanks to get enough momentum to break through the barrier; in some places, two sets of scaffolding were set up, one in the water against boats and one at high water against tanks.[8]

The problem of securing the barriers on sand was overcome by the development of the sword picket by Stewarts & Lloyds – this device was later known at the Admiralty as the Wallace Sword.[7][9]

Barriers varying in length from a couple of hundred feet to three miles were constructed consuming 50% of Britain's production of scaffolding steel[6] at an estimated cost of £6,600 per mile[6] (equivalent to £330,000 today[10]). Despite this, many miles of Admiralty scaffolding were erected using more than 15,000 miles (24,000 km) of scaffolding tube.[9]

After the war, the scaffolding got in the way of swimmers.[11][12] Very soon, the scaffolding was removed for scrap and any remaining traces are now very rare, but are occasionally revealed by storms.[13][14][15][16][17]

See also[edit]



  1. ^ "Beach Scaffolding". Online Thesaurus. English Heritage. Archived from the original on 18 July 2011. Retrieved 16 September 2010. 
  2. ^ "Anti-tank Scaffolding". Online Thesaurus. English Heritage. Archived from the original on 18 July 2011. Retrieved 16 September 2010. 
  3. ^ "The threat of invasion - June-September 1940". Retrieved 2 August 2010. 
  4. ^ "Fear of Invasion - Beach Defences". Historic Cornwall. Cornwall Council - Historic Environment Service. Retrieved 4 August 2010. 
  5. ^ Foot 2006, p. 11.
  6. ^ a b c d e Beach Scaffolding Defence; Trial - WO 199/1618. The Catalogue, The National Archives
  7. ^ a b "Scaffolding". Anti Invasion Defences of Suffolk. Retrieved 30 August 2010. 
  8. ^ foot 2006, pp. 130-137.
  9. ^ a b Wills 1985, p. 42.
  10. ^ UK Retail Price Index inflation figures are based on data from Clark, Gregory (2017). "The Annual RPI and Average Earnings for Britain, 1209 to Present (New Series)". MeasuringWorth. Retrieved 6 November 2017. 
  11. ^ Ann Broad. "Beach Scaffolding Makes for Difficult Swimming on the Sussex Coast". Walberswick Coastal Defences of World War II. Retrieved 4 August 2010. 
  12. ^ Removal Of Bathing Ban At Bournemouth. British Pathe. 1944. Retrieved 16 October 2016. 
  13. ^ "Beach scaffolding - Lunan bay, Angus". Archived from the original on 17 July 2010. Retrieved 4 August 2010. 
  14. ^ "Beach Scaffolding, Pig's Bay to Wakering Stairs, Shoeburyness/Gt Wakering". Unlocking Essex's Past. Essex County Council. Retrieved 5 August 2010. [permanent dead link]
  15. ^ "WW2 Coastal Defences Salthouse, Kelling & Weybourne North Norfolk". Archived from the original on 15 August 2010. Retrieved 24 August 2010. 
  16. ^ "Wartime Beach Defences are Revealed at Tregantle Beach, South East Cornwall in 1987/88". Cyber Heritage. Retrieved 23 March 2012. 
  17. ^ Ruddy 2004, p. 25.

General references[edit]

  • Foot, William (2006). Beaches, fields, streets, and hills ... the anti-invasion landscapes of England, 1940. Council for British Archaeology. ISBN 1-902771-53-2. 
  • Ruddy, Austin (2003). British Anti-Invasion Defences 1940–1945. Official Handbook of the Pillbox Study Group. Historic Military Press. ISBN 1-901313-20-4. 
  • Wills, Henry (1985). Pillboxes: A Study of UK Defences. Leo Cooper. ISBN 0-436-57360-1. 


Further reading[edit]