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Concertina wire or Dannert wireis a type of barbed wire or razor wire that is formed in large coils which can be expanded like a concertina (a small hand-held bellows-type instrument in the same family as the accordion). In conjunction with plain barbed wire (and/or razor wire/tape) and steel pickets, it is most often used to form military-style wire obstacles. It is also used in non-military settings, such as when used in prison barriers, detention camps, riot control, or at international borders. During World War I, soldiers manufactured concertina wire themselves, using ordinary barbed wire. Today, it is factory made.
In World War I, barbed wire obstacles were made by stretching lengths of barbed wire between stakes of wood or iron. At its simplest, such a barrier would resemble a fence as might be used for agricultural purposes.The double apron fence comprised a line of pickets with wires running diagonally down to points on the ground either side of the fence. Horizontal wires were attached to these diagonals.
More elaborate and formidable obstructions could be formed with multiple lines of stakes connected with wire running from side-to-side, back-to-front, and diagonally in many directions. Effective as these obstacles were, their construction took considerable time.
Barbed wire obstacles were vulnerable to being pushed about by artillery shells; in World War I, this frequently resulted in a mass of randomly entangled wires that could be even more daunting than a carefully constructed obstacle. Learning this lesson, World War I soldiers would deploy barbed wire in so-called concertinas that were relatively loose. Barbed wire concertinas could be prepared in the trenches and then deployed in no-man's-land relatively quickly under cover of darkness.
There was what might be called a concertina craze on: innumerable coils of barbed wire were converted into concertinas by the simple process of winding them round and round seven upright stakes in the ground; every new lap of wire was fastened to the one below it at every other stake by a twist of plain wire; the result, when you came to the end of a coil and lifted the whole up off the stakes was heavy ring of barbed wire that concertina'd out into ten-yard lengths.
Concertina wire packs flat for ease of transport and can then be deployed as an obstacle much more quickly than ordinary barbed wire, since the flattened coil of wire can easily be stretched out, forming an instant obstacle that will at least slow enemy passage. Several such coils with a few stakes to secure them in place are just as effective as an ordinary barbed wire fence, which must be built by driving stakes and running multiple wires between them.
A platoon of soldiers can deploy a single concertina fence at a rate of about a kilometer (5⁄8 mile) per hour. Such an obstacle is not very effective by itself (although it will still hinder an enemy advance under the guns of the defenders), and concertinas are normally built up into more elaborate patterns as time permits.
Today, concertina wire is factory made and is available in forms that can be deployed very rapidly from the back of a vehicle or trailer.
Oil-tempered barbed wire was developed during World War I; it was much harder to cut than ordinary barbed wire. During the 1930s, German Horst Dannert developed concertina wire of this high-grade steel wire. 50 feet (15 m) long and each coil could be held in place with just three staples hammered into the ground.The result was entirely self-supporting; it did not require any vertical posts. An individual Dannert wire concertina could be compressed into a compact coil that could be carried by one man and then stretched out along its axis to make a barrier
Dannert wire was imported into Britain from Germany before World War II.During the invasion crisis of 1940–1941, the demand for Dannert wire was so great that some was produced with low manganese steel wire which was easier to cut. This material was known as "Yellow Dannert" after the identifying yellow paint on the concertina handles. To compensate for the reduced effectiveness of Yellow Dannert, an extra supply of pickets were issued in lieu of screw pickets.
A barrier known as a triple concertina wire fence consists of two parallel concertinas joined by twists of wire and topped by a third concertina similarly attached. The result is an extremely effective barrier with many of the desirable properties of a random entanglement. A triple concertina fence could be deployed very quickly: it is possible for a party of five men to deploy 50 yards (46 m) of triple concertina fence in just 15 minutes. Optionally, triple concertina fence could be strengthened with uprights, but this increases the construction time significantly.
Concertina wire is sometimes mistakenly called "constantine" wire. Constantine probably came from a corruption/misunderstanding of concertina and led to confusion with the Roman Emperor Constantine. This, in turn, has led to some people trying to differentiate between concertina wire and constantine wire by assigning the term constantine wire to what is commonly known as razor wire. In contrast to the helical construction of concertina wire, razor wire, or less commonly, constantine wire, consists of a single wire with teeth that project periodically along its length.
A fence is a structure that encloses an area, typically outdoors, and is usually constructed from posts that are connected by boards, wire, rails or netting. A fence differs from a wall in not having a solid foundation along its whole length.
Barbed wire, also known as barb wire, occasionally corrupted as bobbed wire or bob wire, is a type of steel fencing wire constructed with sharp edges or points arranged at intervals along the strands. It is used to construct inexpensive fences and is used atop walls surrounding secured property. It is also a major feature of the fortifications in trench warfare.
Barbed tape or razor wire is a mesh of metal strips with sharp edges whose purpose is to prevent passage by humans. The term "razor wire", through long usage, has generally been used to describe barbed tape products. Razor wire is much sharper than the standard barbed wire; it is named after its appearance but is not razor sharp. The points are very sharp and made to rip and snag clothing and flesh.
A combat engineer is a type of soldier who performs military engineering tasks in support of land forces combat operations. Combat engineers perform a variety of military engineering, mining, construction and demolition tasks under combat conditions.
A Bangalore torpedo is an explosive charge placed within one or several connected tubes. It is used by combat engineers to clear obstacles that would otherwise require them to approach directly, possibly under fire. It is sometimes colloquially referred to as a "Bangalore mine", "banger" or simply "Bangalore".
In the military science of fortification, wire obstacles are defensive obstacles made from barbed wire, barbed tape or concertina wire. They are designed to disrupt, delay and generally slow down an attacking enemy. During the time that the attackers are slowed by the wire obstacle they are easy to target with machinegun and artillery fire. Depending on the requirements and available resources, wire obstacles may range from a simple barbed wire fence in front of a defensive position, to elaborate patterns of fences, concertinas, "dragon's teeth" and minefields hundreds of metres thick.
The cheval de frise is a defensive obstacle, which existed in a number of forms and were employed in various applications. These included underwater constructions used to prevent the passage of ships or other vessels on rivers, or as anti-cavalry measure consisting of a portable frame covered with many projecting long iron or wooden spikes or spears. They were principally intended as an anti-cavalry obstacle but could also be moved quickly to help block a breach in another barrier. They remained in occasional use until they were replaced by wire obstacles just after the American Civil War. During the Civil War, the Confederates used this type of barrier more often than the Union forces. During World War I, armies used chevaux de frise to temporarily plug gaps in barbed wire. Barbed wire chevaux de frise were used in jungle fighting on the South Pacific islands during World War II.
An electric fence is a barrier that uses electric shocks to deter animals and people from crossing a boundary. The voltage of the shock may have effects ranging from discomfort to death. Most electric fences are used today for agricultural fencing and other forms of animal control, although they are also used to protect high-security areas such as military installations or prisons, where potentially lethal voltages may be used.
Dragon's 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.
The McNamara Line, an operational strategy employed by the United States in 1966–1968 during the Vietnam War, aimed to prevent infiltration of South Vietnam by NVA forces from North Vietnam and Laos. Physically, the McNamara Line ran across South Vietnam from the South China Sea to the Laotian border along the Vietnamese Demilitarized Zone (DMZ). The eastern part included fortified field segments, with Khe Sanh as linchpin, along with stretches where roads and trails were guarded by high-tech acoustic and heat-detecting sensors on the ground and interdicted from the air. Assorted types of mines, including so-called gravel mines, and troops at choke points backed sophisticated electronic surveillance. Named the barrier system by Robert McNamara, it was one of the key elements, along with gradual aerial bombing, of his war strategy in Vietnam.
A screw picket is a metal device which is used to secure objects to the ground. Today, screw pickets are used widely to temporarily "picket" dogs. They are also used to graze animals such as sheep, goats, and horses. Screw pickets are also used to stabilize small trees, tent poles, and other objects that are intended to remain upright.
Wiring parties,, were used during World War I on the Western Front as an offensive countermeasure against the enemy’s barbed wire obstacles. Though hazardous and stressful duty, work was done at night to repair, improve, and rebuild their own wire defences, while also sabotaging and cutting the enemy's. In battles all across the Western Front, cutting parties were successful in creating breaches in the wire lines, offering their comrades a better chance to cross no man's land.
Barbed wire was one of the attacker's great problems. There were cutters, but not enough, and men were often killed before they could cut a way.
The fortifications of the inner German border comprised a complex system of interlocking fortifications and security zones 1,381 kilometres (858 mi) long and several kilometres deep, running from the Baltic Sea to Czechoslovakia. The outer fences and walls were the most familiar and visible aspect of the system for Western visitors to the border zone, but they were merely the final obstacle for a would-be escapee from East Germany. The complexity of the border system increased steadily until it reached its full extent in the early 1980s. The following description and the accompanying diagram describe the border as it was around 1980.
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 South West England during the invasion crisis of 1940-1941. Scaffolding was also used, though more sparingly, inland.
A border barrier is a separation barrier that runs along or near an international border. Such barriers are typically constructed for border control purposes such as curbing illegal immigration, human trafficking, and smuggling. Some such barriers are constructed for defence or security reasons. In cases of a disputed or unclear border, erecting a barrier can serve as a de facto unilateral consolidation of a territorial claim that can supersede formal delimitation. A border barrier does not usually indicate the location of the actual border, and is usually constructed unilaterally by a country, without the agreement or cooperation of the other country.
In 2015, Hungary built a border barrier on its border with Serbia and Croatia. The fence was constructed during the European migrant crisis, with the aim to ensure border security by preventing illegal immigrants from entering, and enabling the option to enter through official checkpoints and claim asylum in Hungary in accordance with international and European law. The number of illegal entries to Hungary declined greatly after the barrier was finished as it effectively abolished the access to asylum in Hungary.
The Slovenian border barrier is a border barrier constructed by Slovenia in 2015–2016 on its border with Croatia as a response to the European migrant crisis. Both Slovenia and Croatia are European Union members, therefore the barrier is located on an internal EU border; but currently only Slovenia is a member of the free travel Schengen Area, which Croatia is expected to join sometime in the future. In March 2016, Slovenia announced that only migrants who apply for asylum in Slovenia and those with clear humanitarian needs will be allowed to enter Slovenian territory.
Perimeter security refers to natural barriers or built fortifications to either keep intruders out or to keep captives contained within the area the boundary surrounds.
The Bulgaria–Turkey border is a 269 km (167 mi) long international border between the Republic of Bulgaria and the Republic of Turkey. It was established by the Treaty of San Stefano in 1878 as an inner border within the Ottoman Empire. The current borders are defined by the Treaty of Constantinople (1913) and the Bulgarian–Ottoman convention (1915). The border was reaffirmed by the Treaty of Lausanne ten years later, though Bulgaria was not a party to the latter treaty as it had earlier ceded to Greece that part of its border with Turkey which was modified by the Bulgarian-Ottoman convention.
The flexible defense is a military theory about the design of modern fortifications. The examples of "flexible" defense-lines are not based on dense lines of heavily armed, large and expensive concrete fortifications as the systems such as the Maginot Line were. Their protective capacity hinges on multiple lines of obstacles and small shelters fitting into the environment. They are "flexible" because soldiers are not locked in pillboxes, but fight instead in easily replaceable open earth-wood made positions, while bunkers serve only as shelters during bombardments. As a result, they are able to adapt to the opponent's movements, and there are no easily targeted large buildings in these lines.