Admiralty scaffolding
Encyclopedia
Admiralty scaffolding, also known as Obstacle Z.1 or sometimes simply given as beach scaffolding or anti-tank scaffolding, 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
. Scaffolding was also used, though more sparingly, inland.
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 in 10 in (1.47 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. 20 feet (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.
However, trials found that a 250 ton barge
at 5+1/2 kn or an 80 ton trawler at 7+1/2 kn would pass through the obstacle as if it were not there and a trawler easily pulled out one bay with an attached wire rope. 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 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.
The problem of securing the barriers on sand were overcome by the development of the sword picket by Stewarts & Lloyds
– this device was later known at the Admiralty
as the Wallace Sword.
Barriers varying in length from a couple of hundred feet to three miles were constructed consuming 50% of Britain's production of scaffolding steel at an estimated cost of £6,600 per mile (equivalent to £ today). Despite this, many miles of Admiralty scaffolding were erected using more than 15000 miles (24,140.1 km) of scaffolding tube.
After the war, the scaffolding got in the way of swimmers. Very soon, the scaffolding was removed for scrap and any remaining traces are now very rare, but are occasionally revealed by storms.
South East England
South East England is one of the nine official regions of England, designated in 1994 and adopted for statistical purposes in 1999. It consists of Berkshire, Buckinghamshire, East Sussex, Hampshire, Isle of Wight, Kent, Oxfordshire, Surrey and West Sussex...
, eastern England
East of England
The East of England is one of the nine official regions of England. It was created in 1994 and was adopted for statistics from 1999. It includes the ceremonial counties of Essex, Hertfordshire, Bedfordshire, Cambridgeshire, Norfolk and Suffolk. Essex has the highest population in the region.Its...
and the south western peninsula
South West England
South West England is one of the regions of England defined by the Government of the United Kingdom for statistical and other purposes. It is the largest such region in area, covering and comprising Bristol, Gloucestershire, Somerset, Dorset, Wiltshire, Devon, Cornwall and the Isles of Scilly. ...
during the invasion crisis of 1940-1941
British anti-invasion preparations of World War II
British anti-invasion preparations of the Second World War entailed a large-scale division of military and civilian mobilisation in response to the threat of invasion by German armed forces in 1940 and 1941. The British army needed to recover from the defeat of the British Expeditionary Force in...
. Scaffolding was also used, though more sparingly, inland.
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 in 10 in (1.47 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. 20 feet (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.
However, trials found that a 250 ton barge
Barge
A barge is a flat-bottomed boat, built mainly for river and canal transport of heavy goods. Some barges are not self-propelled and need to be towed by tugboats or pushed by towboats...
at 5+1/2 kn or an 80 ton trawler at 7+1/2 kn would pass through the obstacle as if it were not there and a trawler easily pulled out one bay with an attached wire rope. 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 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.
The problem of securing the barriers on sand were overcome by the development of the sword picket by Stewarts & Lloyds
Stewarts & Lloyds
Stewarts & Lloyds was a steel tube manufacturer with its headquarters based at Corby, Northamptonshire, England. The company was created in 1903 by the amalgamation of two of the largest iron and steel makers in Britain, A. & J. Stewart & Menzies Ltd, Coatbridge, North Lanarkshire, Scotland and...
– this device was later known at the Admiralty
Admiralty
The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...
as the Wallace Sword.
Barriers varying in length from a couple of hundred feet to three miles were constructed consuming 50% of Britain's production of scaffolding steel at an estimated cost of £6,600 per mile (equivalent to £ today). Despite this, many miles of Admiralty scaffolding were erected using more than 15000 miles (24,140.1 km) of scaffolding tube.
After the war, the scaffolding got in the way of swimmers. Very soon, the scaffolding was removed for scrap and any remaining traces are now very rare, but are occasionally revealed by storms.
See also
- British anti-invasion preparations of World War IIBritish anti-invasion preparations of World War IIBritish anti-invasion preparations of the Second World War entailed a large-scale division of military and civilian mobilisation in response to the threat of invasion by German armed forces in 1940 and 1941. The British army needed to recover from the defeat of the British Expeditionary Force in...
- British hardened field defences of World War IIBritish hardened field defences of World War IIBritish hardened field defences of World War II were small fortified structures constructed as a part of British anti-invasion preparations. They were popularly known as pillboxes by reference to their shape.-Design and development:...