User:Gaius Cornelius/Anti-tank obstacle

An anti-tank obstacle (also known as tank obstacle) is any natural or artificial obstruction which will cause military vehicles, especillay tanks, to stop, slow down, maneouver or change direction.

Anti-tank obstacles were introduced shortly after the advent of Armoured Fighting Vehicles (AFVs) during the First World War when tanks at least partially addressed the problem of crossing open ground under enemy fire. Even the earliest tanks were able to cross ditches and trenches, pass over or through hedgerows and walls and to crush barbed wire entanglements. Commanders sought to find obstacles that would stop tanks rolling through defensive lines.

Anti-tank ditches
Thousands of miles of anti-tank ditches were dug, usually by mechanical excavators, but occasionally by hand. They were typically 18 ft wide and 11 ft deep and could be either trapezoidal or triangular in section with the defended side being especially steep and revetted with whatever material was available.

Czech hedgehog


The Czech hedgehog (rozsocháč) was a static anti-tank obstacle defence made of angled iron (that is, lengths with an L- or H- shaped cross section) deployed during World War II by various combatants.

The hedgehog is very effective in keeping tanks from getting through a line of defence. It maintains its function even when tipped over by a nearby explosion. Although it may provide some scant cover for infantry, infantry forces are generally much less effective against fortified defensive positions than mechanized units.

Dragon's teeth


Dragon's teeth (Drachenzähne, literally "dragon teeth") are square-pyramidal fortifications of reinforced concrete first used during the Second World War to impede the movement of tanks and mechanised infantry. The idea was to slow down and channel tanks into "killing zones" where they could easily be disposed of by anti-tank weapons.

Pimples, popularly known as Dragon's teeth, were pyramid shaped concrete blocks designed specifically to counter tanks which, attempting to pass them, would climb up exposing vulnerable parts of the vehicle and possibly slip down with the tracks between the points. They ranged in size somewhat, but were typically 2 ft high and about 3 ft square at the base. There was also a conical form.

Concrete blocks


Anti-tank barriers were made of massive reinforced concrete obstacles, either cubic, pyramidal or cylindrical. The cubes generally came in two sizes: 5 or high. In a few places, anti-tank walls were constructed&mdash;essentially continuously abutted cubes.

Large cylinders were made from a section of sewer pipe 3 to 4 ft in diameter filled with concrete typically to a height of 4 to 5 ft, frequently with a dome at the top. Smaller cylinders cast from concrete are also frequently found.

Cubes, cylinders and pimples were deployed in long rows, often several rows deep, to form anti-tank barriers at beaches and inland. They were also used in smaller numbers to block roads. They frequently sported loops at the top for the attachment of barbed wire. There was also a tetrahedral or caltrop-shaped obstacle, although it seems these were rare.

Pallisades
Where natural anti-tank barriers needed only to be augmented, concrete or wooden posts sufficed.

Admiralty scaffolding

Crater mines
The Canadian Pipe Mine (later known as the McNaughton Tube after General Andrew McNaughton) was a horizontally bored pipe packed with explosives – once in place this could be used to instantly ruin a road or runway. This produced a very effective anti-tank obstacle about 28 ft wide and 8 ft deep with loose soil at the bottom.

Roadblocks


Roads offered the enemy fast routes to their objectives and consequently they were blocked at strategic points. Many of the road-blocks formed by Ironside were semi-permanent. In many cases, Brooke had these removed altogether, as experience had shown they could be as much of an impediment to friends as to foes. Brooke favoured removable blocks.

The simplest of the removable roadblocks consisted of concrete cylinders of various sizes but typically about 3 ft high and 2 ft in diameter; these could be manhandled into position as required. However, these would be insufficient to stop armoured vehicles. One common type of removable anti-tank roadblock comprised massive concrete posts permanently installed at the roadside; these posts had holes and/or slots to accept horizontal railway lines or rolled steel joists (RSJs). Similar blocks were placed across railway tracks because tanks can move along tracks almost as easily as they can along roads. These blocks would be placed strategically where it was difficult for a vehicle to go around&mdash;anti-tank obstacles and mines being positioned as required&mdash;and they could be opened or closed within a matter of minutes.

Socket Roadblocks


There were two types of socket roadblocks. The first comprised vertical lengths of railway line placed in sockets in the road, was known as hedgehog. The second type comprised railway lines or RSJs bent or welded at around a 60° angle, known as hairpins. In both cases, prepared sockets about 6 in square were placed in the road, closed by covers when not in use, allowing traffic to pass normally.

Another removable roadblocking system used mines. The extant remains of such systems superficially resemble those of hedgehog or hairpin, but the pits are shallow: just deep enough to take an anti-tank mine. When not in use, the sockets were filled with a wooden plug allowing traffic to pass normally.



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 * - 'WW2 People's War is an online archive of wartime memories contributed by members of the public and gathered by the BBC
 * - 'WW2 People's War is an online archive of wartime memories contributed by members of the public and gathered by the BBC