Scaffolding was devised initially by the Navy to replace off shore nets laid to hinder invasion barges. The Armillary identified the beaches at Felixstowe (4 miles), Aldebrugh to Thorpeness (2 miles) and Thorpeness to Lowestoft (18 miles) to be part of the first allocation. Three designs were apparently considered – Z0, Z1 and Z2. Z1 was found to be the best and the one used. A plan of Z1 is shown below although there are no plans of Z0 or Z2 in the records. It was initially intended to site it below the high water mark (so that the water depth would be about 3 ft at high tide) to hinder landing craft. However trials at Felixstowe found that:
a) A 250 ton barge at 5 ½ knots went straight through the obstacle as if it were not there
b) A 80 ton trawler at 7 ½ knots also went clean through the obstacle
c) A trawler easily pulled out one bay with an attached wire rope.
Above: Left - plan of Z1 scaffolding. Right - troops erecting scaffolding somewhere in the UK.
The commander of 4th Coprs, when inspecting scaffolding erected below the high water mark found that within three weeks, sections had been dislodged despite no recent rough weather. He was concerned that it would not withstand the expected winter gales.
The result of these trials was to site any new beach works at about the high water mark, so that heavier barges and landing craft could not ram it before they ground. Eastern Command ordered that any scaffolding already laid below the HW mark to be re-sited. If there was a danger of encountering mushroom mines, scaffolding was to be sited on the landward side of minefields. Also 50% of the allotment was now to be made available to the army for use as an anti-tank obstacle (the other 50% still going to the Navy).
Trials were also held to assess the effectiveness of scaffolding as an anti-tank barrier. A test carried out by Southern Command on March 26th 1941 resulted in a 26 ton tank easily being able to break through. Tests at the Anti-tank Experimental Station on 13 May 1941 showed that with frames of 5 ft and 4 ft spacing had no impact on a tank approaching at a reasonable speed. Frames at 3 ft spacing did stop the tank on the first two attempts. The obstacle failed at the couplings, either the tube pulling out or the hinge of the coupler or coupler bolt sheared. Although the scaffolding tested at the Experimental Station was not the standard naval design, it was concluded that scaffolding would be an effective obstacle if the speed of the tank was slowed right down.
Military Training Pamphlet Part III Obstacle states that sand/shingle would slow tanks down approaching the obstacle sited above the HW mark. If used as a road block or an inland anti-tank barrier, natural obstacles or a ditch dug in front of the scaffolding should be used to slow down the tank speed.
Mines were to be attached to anti-boat scaffolding. A trial to test the damage to the scaffolding by the exploding of a mine carried out in December 1941 showed that the damage done to the obstacle would allow a boat drawing up to 6 ft of water could pass at high tide. It would appear that the only anti-boat scaffolding erected in Suffolk was a small stretch at Aldeburgh. For scaffolding erected as an anti-tank obstacle, it was to be reinforced with barbed wire to hamper an infantry attack.
Above: Results of trials to test the damage to scaffolding by the explosion of a mine.
Scaffolding work began in Suffolk late 1940/early 1941 in the Felixstowe area. The delay in deciding the final role of scaffolding limited the amount of work that could be carried out, with both 11 Corps and Eastern Command frequently ordering the work to be halted. This naturally caused frustration to the troops on the ground with CRE 42nd Division noting that scaffolding was ”more of a correspondence source than tank obstacle”, with the final instructions for the obstacle only being received in January 1941.
Further delays were experienced with shortages of couplers which halted work in February. Transport was also a problem due to the number of limited stations where supplies could be offloaded along the coast. The presence of unsafe minefields also caused some delay. Again, CRE 42 Div noted somewhat in frustration that: “Lt. Cmdr Owen , Beach Defence Officer, Landgaurd, is O.C. Tubular Scaffolding Obstacle and is responsible for indicating to the Military exactly where the obstacle has to be placed on all parts of the Div. front. He is a dammed nice fellow but seems to have no control whatsoever over delivery of the tubes in the right place, at the right time and in the right quantities, which is unfortunate”.
From the Home Forces war diaries of units based in Suffolk, it would appear that these problems were largely overcome by the Spring of 1941, with work beginning in earnest on scaffolding from March 1941 and continued right through the summer. For example the war diary of 11th HLI is full of references to work on Scaffolding throughout May to July, including working parties unloading scaffolding at Woodbridge station. In some areas, anti-tank blocks were apparently removed and replaced by scaffolding as the blocks masked field of fire (6th KOSB war diary).
Troops were not expected to maintain scaffolding during the winter months where gales were likely to cause damage. Plans were however expected to be in place to carry out any work necessary for the Spring invasion season.
As well as a beach defence obstacle, some towns in Suffolk were provided with scaffolding as part of their anti-tank obstacles. Plans to site anti-tank scaffolding between Orford and Alderton had to be put in abeyance as no troops were available to erect it.
Right: Scaffolding erected in Suffolk.
Tubular Scaffolding, TNA
Experiments with ant-tank obstacles, TNA
Troops erecting Z1 naval scaffolding - also note standard 5ft cubes and wire obstacle
Field Engineering (All Arms), Military Training Pamphlet No.30 Part III Obstacles, War Office, 1943
Tubular Scaffolding, TNA
Experiments with ant-tank obstacles,TNA
East Anglia at War 1939-1945, D.E Johnson, Jarrold,1992