In response to “Some Practical Experience with Concertina Wire” I would like to add a bit about my experience with the stuff. About twenty years ago I was deployed to Somalia during Operation Restore Hope. I was in a combat arms unit tasked with providing convoy escorts, roadblocks and checkpoints, Quick Reaction Force (QRF) Teams and perimeter security to supply areas and support units.
For several weeks we were working as perimeter security for a Quartermaster Company which had commandeered a vacant embassy and its surrounding fortifications. I say fortifications because all of the old embassies and foreign corporate campuses had twelve foot tall walls topped with broken glass, guard towers and hardened gun positions. This particular embassy compound was six or seven buildings sitting on about eight acres surrounded all the way around by a twelve foot tall mud-brick wall covered with stucco and topped with broken glass… except two-thirds of the way back on the western side. At some point the wall had been breached with explosives, and a section nearly twenty feet wide had been reduced to a pile of rubble.
The Quartermaster Company had strung row after row of concertina wire in the gap. To soft American eyes the wire looked formidable. But looked at by Somalis used to a brutally difficult daily existence, that gap in the wall was an open invitation to pillage. During the short period that we were providing security we caught dozens of Somalis, mostly grade school age children, crawling through the row after row of wire. We would watch in amazement as seven year olds would grab the wire with their bare hands and adjust the gaps so that they could work towards the compound. The cutting edges of the wire seemed to have no effect at all on their skin. Mostly the barbs hung up on their clothing and slowed them down. Prior to my unit’s arrival, the rear-echelon types had been unable to determine how the Somalis kept getting into their perimeter and stealing. It was inconceivable to them that anyone, let alone children, would risk that wire so that they could steal a canteen cup or a roll of commo wire. But every night they would climb right through and loot the camp.
I suppose that in a nutshell what I’m saying about concertina wire is this: Realize that it will slow down intruders, but it will not stop determined, desperate people who want what you have. Don’t depend on concertina wire or any other inanimate fortification to secure your six, or you’re liable to wake up dead. – An Old 16R
I spent significant time as a USMC tanker in a combat operations. Not only is reader P.J.B. correct, but the same is true for barbed wire and even to some extent, thick commo wire. The deal is, as the wire is drawn up and around the vehicles sprockets, road wheels, and support rollers, it become wound more tightly and the wire tears out grease seals, eventually resulting in a "mobility kill". With significant enough volume, the wire can bind the wheels, rollers, and sprockets themselves bringing the vehicle to a halt. Now, it is very important to note that an armored vehicle can remain effective as base of fire even while immobile. That said, most armor crews will do their level best to avoid wire whenever possible because it is almost impossible to fish out wire from the track and sprockets without the type of maintenance that requires dead-lining the vehicle in a maintenance area. So, knowing this what is the lesson? Quantities of visible wire of all sorts can be a very effective way to channel armor into predictable avenues of approach. – Tanker John