- Barbed wire obstacles, fences and entanglements, are perhaps a more familiar feature of the First World War than the Second, but they formed an important part of coastal defence. Barbed wire was intended to disrupt, delay and slow down attacking infantry. While delayed in negotiating barbed wire obstacles, enemy infantry became easier targets for small arms or artillery fire.
- The barbed wire employed at Walberswick took two forms: Concertina and Double Apron. Concertina wire was constructed from large (approximately 4ft) coils of the then modern, strong and stiff 'Dannert' wire which were opened up to form the characteristic concertina-like shape. These were then erected in the form of a pyramid with two coils below and one on top. The coils were then connected with wire and the whole structure secured to wooden posts or metal pickets
- Double Apron took longer to construct but was thought by the military to be one of the best types of barbed wire entanglements because it was difficult to cut, climb over or destroy by artillery fire. It consisted of three horizontal wires fixed to pickets (vertical supports) with sloping wires (diagonals) leading from the top of the upright pickets to the anchorage pickets. Three further horizontals were fixed to these diagonals. These horizontals, together with the diagonals, were called 'front and rear aprons'.
- When combined with concertina, barbed wire would present a very effective obstruction. The construction of both forms is best illustrated by the photo below, which shows textbook wiring consisting of two Double Apron fences with Concertina entanglements in-between.
British Barbed Wire Entanglements in Northern France in the winter of 1939-40. Similar entanglements were constructed at Walberswick. (Imperial War Museum)
- At Walberswick, wire obstacles were laid along the beach, parallel to the sea, just above high water level.
- In order to stop any invaders moving along the beach, entanglements were also added. These were slightly higher up the beach and often at right angles to the first set of wire, which was to have the effect of channelling any Germans into 'killing zones' where they could be dispatched.
- The barbed wire obstacles were one of the first defences to constructed; as early as May 1940 there are references to Dannert wire being put in place and by June it was also being placed around the newly built pillboxes and trenches.
- By the end of the year the wiring was still being strengthened, with orders to put in place three rows of Double Apron, or the equivalent, on all possible landing beaches. The impression is given that, at least in May and June 1940, Concertina defences were more common than Double Apron.
- In addition to that placed on the beaches,all defensive positions were protected by barbed wire. The wire had to be covered by some kind of small arms fire but also, in the case of the section trenches, had to be out of hand grenade range.
- Barbed wire fences were highly visible from the air and if erected in a circle gave away the location of the position it was intended to protect.
- Instructions were therefore given that, wherever possible, wire fences should be laid out in an irregular fashion and extended to merge into neighbouring hedges or natural features.