Constructing a Triple-Strand Concertina Wire Obstacle, by CPT Blackfox

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Digging fighting positions, trenches, and emplacing various obstacles take a great deal of time and effort.  The greatest danger in emplacing obstacles is not being thorough enough due to the difficulty involved.  Stringing out wire and actually driving the pickets into the ground not only gives you good practice as how to physically create the obstacle but also gives you an idea of the challenges you will face and how long it takes to put up 100 lineal meters of obstacle.

Triple-strand concertina wire obstacles consist of two rolls of concertina wire side-by-side on the bottom with one roll on top.  From the side, the obstacle resembles a pyramid.  I will be going through this obstacle and how to emplace it, because it is the most difficult of all wire obstacles to breach and much easier to emplace than a concrete, wood, or earth barrier.

Resources Needed

It is possible to emplace obstacles by yourself, but it ends up taking much more time alone than it would with a group of two or three people.  Concertina wire or razor wire tends to snag on itself, so it’s better to have one person on each end of the coil instead of letting one person struggle through stringing out wire on his own.  If you have another person willing to help, he can get ahead and lay out pickets every five paces or five meters and dropping coils of concertina wire every 20 meters. 

You need a pair of wire gloves for each person stringing wire.  Heavy-duty leather gloves will work, but since concertina wire has little nasty razors on it, it can cut up a pair of leather gloves pretty badly if you are not very careful.  If you are a novice or are planning on emplacing several hundred meters of concertina obstacles, you might want to get some reinforced wire handling gloves to protect yourself more adequately.  The military grade gloves are heavy-duty leather gauntlets with staples in the palms and underside of fingers to prevent the concertina wire from snagging the leather.  If you feel industrious, you might be able to improvise something like that with a pair of leather gloves and a heavy-duty plier-type industrial stapler with ¼” or 5/16” staples.   Otherwise, just hold onto the two handles on each end of the concertina coil and be careful to grab the wire between the barbs when you place it on the pickets, and you should do fine.  You will also need a pair of heavy-duty wire cutter pliers for each person stringing wire.

If you are able to get the military grade pickets with the built-in wire loops and the corkscrew bottoms, then that will make life somewhat easier on you in respect to tie-offs to the pickets.  However, using regular green steel "T-Post" agricultural fence pickets presents no problem whatsoever.  You would want to purchase T-Post or U-channel 2 ¼” x 2 ½” x 7’ tall pickets.  You can buy these at most big-box hardware stores or at a farm supply store.  Don’t forget to buy one or two post drivers as well.  If you have ever tried to drive a picket into the ground with a sledgehammer, it’s not fun!  I’ve seen soldiers nearly get into fistfights from the sledge head glancing off the picket and hitting his buddy’s hand instead.

The concertina wire itself is critically important.  Concertina wire is different than razor wire in that when it is expanded, it acts like a concertina or an accordion.  The wire itself is typically spring steel inside of a metal sheathing which has the barbs mechanically attached to it.  Since it is not just a single strand of wire, it is difficult to cut and in the concertina configuration, you must make four cuts to get through a single coil of wire.  If you are purchasing concertina wire, you want a medium sized blade on your wire and you will want to get it in manageable lengths of 20 meters or so.  Along with your concertina wire, you will need barbed wire for triple the length of obstacle you wish to emplace and you will need a roll of baling wire to make your ties from the concertina wire to the pickets.
Be sure to wear jeans, durable pants, or surplus BDU trousers when you string wire, since it will take bites out of your clothing if you are not careful.  Wear a long sleeve denim shirt or a surplus BDU blouse to protect your arms from nasty gashes.  If you are planning on taking down the obstacle later, the best way I have found to store concertina wire is by cutting ½” plywood to size and making a giant sandwich with the wire pancaked in the middle.  Concertina wire snags on everything including itself, and this method keeps all of the barbs between the two pieces of plywood.  And to transport using this method, just drill two pairs of holes on each side of the boards and tie the sandwich together with some parachute cord.  String the cord through the matching pairs of holes in a U-shape and you can make a handle on each side of the sandwich to make it much easier to carry. 

In summary, if you have a three member team emplacing 100 meters of triple-strand concertina wire, this is what you would need:
3 Pair Reinforced wire handling gloves
2 Post drivers
2 Pair of Wire cutter pliers
63 7’ U-channel pickets
15 Rolls of 20 meters of concertina wire
3 Rolls of 100 meters of barbed wire
2 Rolls of baling wire

General Guidance on Obstacle Emplacement
The first thing to keep in mind when emplacing and obstacle, is that it MUST be observable [by defenders]!  You can have the most formidable obstacle in the world, but if it is unobserved, the enemy also has all the time in the world to dismantle your beautiful obstacle without you ever noticing.  The terrain will dictate the routing of your obstacle.  For instance, if you were emplacing an obstacle over a ditch, you need to make sure you follow the contours of the ditch instead of going straight over it, creating a tunnel underneath your wire.  If the ditch were deep enough, you might lose visibility on your obstacle, so you might need to reroute it to get around that blind spot or what is otherwise called “dead space.”  If you can see someone breaching your obstacle, but you have no weapon that has a long enough range to stop them, your obstacle is too far from your position and is utterly useless. 
If you are emplacing an obstacle as a perimeter, you need not worry about where you start or end.  But if you are using an obstacle to slow an enemy avenue of approach, you must tie the start and end of the obstacle into a terrain feature.  If you are in rolling mountainous terrain, you might want to start the obstacle against a boulder and end it against a steep cliff.  Your obstacle does no good if the enemy can follow it and find an easy way around it. 

Which is precisely what an opposing force will do when they encounter your obstacle: try to find a way around it without having to breach it.  Keep that in mind and put yourself in the shoes of someone raiding your land or trying to loot your home.  The best obstacles channel your enemy where YOU want them to go.  And when the enemy finds that “easy way around” they run right into something else very unpleasant.  In general, you want to make it nearly impossible for an assaulting force to come straight at your position.  You want to force them to meander and zigzag through your maze of obstacles, meeting traps on the way and all the while being harassed by rifle or small arms fire.
If you are thorough in setting up your obstacle and consistently drive pickets deep and tie off your wire to the pickets, the enemy will have a very difficult time breaching it.  They are looking for that one spot where you ran into rocky ground and could not drive the pickets deep enough.  If you know where you had to fudge it, count on the enemy figuring that out too.  If you do need to emplace an obstacle across asphalt or concrete, you need to use steel posts with a bolt plate at the bottom, so that you can anchor it to the concrete or asphalt.   Generally speaking , try to avoid placing wire across concrete or asphalt if possible.  

Why Triple-Strand Concertina?

I commanded tanks during my time in the U.S. Army, and a tank can absolutely crush anything on the battlefield.  We had ammunition for bunker, buildings, and field fortifications.  So jersey barriers or earthworks were no big deal.  We had ammunition for shooting helicopters, trucks, troop carriers, other tanks, and dismounted infantry.  There were only four things that I knew of which could stop a tank: land mines, a really deep and wide ditch, a river, or a triple-strand concertina wire obstacle.  And since a tank is the most deadly threat possible, anything less doesn’t stand a chance.
You would think that a tank could punch right through a triple-strand concertina wire barrier, and it can.  It would crush the pickets like toothpicks and stretch the concertina wire until it snaps like a rubber band.  And then the nasty part begins.  The tank tracks pull the concertina wire inside the suspension, winding it around the drive sprocket, road wheels, and support rollers until the tank has a huge rat’s nest of wire tangled throughout the suspension, and it then throws a track.  A tank without track is a bunker. It is still a formidable threat, but tanks are much better at killing threats at a distance.  If you get close enough to a tank, particularly on the sides and directly behind it, there are blind spots where the crew cannot see you and you can assault the tank without receiving fire. 

Tankers know what happens to a tank when they try to breach concertina wire.  They know you can drive through single or even double strand if you are lucky, but that triple-strand barrier will mess up a tank’s suspension so badly, that it takes a crew hours to cut all of the wire out of the suspension and track by hand.  I know this, because it happened to me when we sucked up a roll of single-strand concertina wire lining a road on an airfield.  It took about three hours to cut it all out of the suspension.  We were working with our sister platoon on another airfield in Iraq, and one of the tanks actually wound the wire between the road wheels and behind the wheels on the road wheel arms, pushing the center guide of the track out of its notch between the pairs of road wheels.  When that tank commander rolled up to our tank line, you could hear the distinctive POP, POP, POP of a tank which is about to throw track.  He had not wanted to open the tank skirts and cut it out in the field due to how vulnerable he and his crew would have been to potential sniper fire.  Consequently though, he created a much nastier problem as described above.  My soldiers and I had feelings ranging from disgust to a healthy respect of what concertina wire could do to a tank’s suspension, and I venture to say most tracked vehicle operators share those notions.     

The only way that the U.S. Army trains to breach triple-strand concertina wire obstacles is with explosives.  You have to literally blow it up, because you cannot effectively cut a hole through the obstacle any other way.  A quick word on why I would not recommend just single or double-strand concertina wire obstacles.  All you need to breach a single-strand obstacle is to get a running start and jump over it!  All you need to breach a double-strand concertina obstacle is a piece of plywood that you flop down on top of the wire and walk right over it.  Neither of those methods would work on a triple-strand obstacle though due to its height and the amount of pickets and wire holding the obstacle together.

Obstacle Emplacement

You will need to lay out the first 20 meters of materials before you start.  Throw down three pickets and three rolls of concertina at your starting spot, walk five paces and keep dropping three pickets repeatedly until you get to 20 paces or roughly 20 meters.  The training manuals recommend that you use two small pickets for your lower coils and a long picket for the upper coil on your beginning and end of the obstacle, but I disagree with this method.  It makes it much easier to dismantle the obstacle at the beginning and end.  You want to drive your pickets about a foot down with all three in a straight line as if you were starting to string three parallel barbed wire fences, leaving about 2’ between each picket.  Look at the width of the roll and make sure you are not stretching the wire with your picket spacing but that it is taut when dropped onto the pickets.  Make sure your pickets have the U-channel facing the enemy and pry out your wire hooks a bit from the picket, so that you can more securely tie off your wire to the pickets with baling wire.

At this point, you can start stringing out your lower two rolls of concertina wire.  If you have standard military concertina, the coils will have two handles on each end.  And if the rolls do not, you might want to fashion a couple handles out of baling wire for each end of the coils.  Stringing wire goes more smoothly if one person stands in place and the other person walks backwards while you both shake the coil like a Slinky, so that the barbs release from each other.  String the coils outside of where you will drive your pickets down the line, so that you can more easily put the wire onto the pickets once they are in the ground. 

Come back to your first three pickets and place the end of the inner coil over the top of the inner and center picket.  Take the other coil of concertina toward the enemy and place the coil over the outer and center picket.  Now you cut a few 6” lengths of baling wire and tie the rear coil to the inner picket and center picket and the front coil to the center picket and the outer picket.  Put a couple of twists in your tie off and bend the ends down, so that it is difficult to pull apart without pliers or wire cutters. 

Go to your next three pickets on the ground and drive those into the ground with the same spacing as before.  Take the inner coil of concertina and place over the inner and center picket.  Take the outer coil of concertina and place over the center and outer picket.  Then tie off the concertina wire to the pickets.  This process repeats for the bottom two coils until you reach the end of your concertina wire rolls.  As you place the bottom two coils, go back to the starting point and attach barbed wire to the center picket about 12” off the ground.  Then you weave the barbed wire through the two coils of concertina to join them together by going along in front or behind the obstacle and pushing the small roll of barbed wire in and out between your two lower concertina rolls.  This is a pain, but it makes the two bottom coils very secure as one unit.  If the enemy tries to lift the outer coil, they will then be lifting the inner coil too and will not be able to slide under your obstacle.  This and tying off your wire to the pickets are those little things that make the difference between a formidable obstacle and something that can be bypassed in a matter of minutes.

You want to string the wire between each group of three pickets taut but not so tight that it stretches and looks misshapen.  If the wire is strung so loosely, that you can crawl underneath it by prying it up with a branch, you need to string it tighter.  Check your obstacle as you go.  Shake the pickets, jerk on the tie off points, and try to pry up the wire at the base.  If you find any weaknesses, adjust accordingly.  You might need to place your groups of pickets closer together if you have rolling terrain, or if it is easy to dig under your obstacle.

If you are putting up this obstacle in response to some crisis event, I would advise finishing the entire obstacle in double-strand concertina first and then going back to throw the last roll on top along the whole obstacle.  If you run out of time, it would be better to have a complete perimeter with double-strand than to have it half completed with triple-strand. 

Once you have completed the first section of 20 meters of double-strand, go back to the starting point and put your top roll of concertina onto the center picket.  Tie off the end of the top coil very securely to where the top of the roll meets the picket, because if someone tries to go over the top of your obstacle, this is going to be holding the weight of that log or other breaching material.  Tie off the bottom of the top coil to the middle picket as well.  Looking at it from the side, this top coil will be bisected by the pickets when you are done tying off the coil to the center pickets. String the top roll out to the next group of three pickets and secure the roll in the same way over the top of the center picket.  In the same way that you wove barbed wire between the two bottom coils, you will weave the wire between the top coil and the two bottom coils to join them.  This way, the enemy cannot try to pry their way through the middle of your obstacle by simply lifting your top coil of wire off the pickets and smashing the bottom two coils, making a tunnel to breach through it.  If you are using green U-channel pickets, it would be wise to string one more length of barbed wire to keep the top concertina roll taut by suspending it like a clothesline near the tops of the two center pickets.  Remember to wrap your barbed wire around the pickets a couple times to maintain tension as you continue to string it between the coils of concertina wire on both the lower coils and the upper coil.

When you get to the end of your first 20 meters of obstacle, you will need to start with new rolls of concertina wire.  You will notice that the ends of the concertina rolls have a convex and concave part to them.  You will have these two loops at the end of a roll, because of how the wire pattern stops.  In order to securely join the end of a roll to the beginning of a new roll, you need to place the bottom loop of the old roll over the picket then the bottom loop of the new roll over the picket.  Then you place the top loop of the old roll over the picket and then the top loop of the new roll over the picket.  You are alternating, so that you do not have one roll of wire sitting on top of another when it is placed on the picket.  Tie off both the old and new rolls to the same picket.  This will make a very sturdy continuation in your obstacle so that the enemy will not be able to exploit a weakness between your rolls of wire.  The barbed wire running through the rolls will also aid in reinforcing this transition.  Repeat this same procedure for the top roll later once you start stringing your top coil on the next 20 meters of obstacle, alternating putting the bottom loops and top loops of the old and new rolls of wire over the center picket.  Then join the rolls together with baling wire and tie both the end of the old roll and the start of the new roll off to the same center picket.

Continue this process for emplacing triple-stand concertina until you tie the end of your obstacle into a natural feature such as a boulder or cliff or you complete your perimeter.  Be sure that you tell everyone in your prepper group or family that you are putting up a concertina obstacle, because I have personally run into obstacles emplaced by soldiers during the daytime which I could not see at nighttime when I returned to the base and had to figure out where they put the entrance to the perimeter.  If you have created a 360 degree perimeter with your obstacle, depending on the size, you might have only one entrance or two if it is a larger perimeter.  Mark your entrances with a small handkerchief or a partially masked glow stick at night until everyone knows where they are. 

Your entrance should be directly opposite of the most likely avenue of approach by the enemy.  You should have the entrance at the backdoor of the property for tactical purposes.  If the road dead-ends at the front of your home or you have a driveway, you might need an entrance there for practical purposes but in cases of imminent attack, that entrance needs to be well sealed and the backdoor would become your primary entrance since it is the furthest away from the path of the enemy. 

Continuously Improving Your Position

Once you have completed emplacing an obstacle, you are never really done with it.  Over an extended period of time, obstacles need to be checked periodically and repaired as needed.   Obstacles and barriers should work together in concert in order to fortify your defensive plan.  As you continue to fortify, obstacles should be implemented in defensive rings around a position.  If we had just completed emplacing a triple-strand concertina wire perimeter around a homestead, we would continue fortifying by driving in pickets along the entrance to the property in preparation for a layered concertina wire roadblock.  We could also add tin cans or bells tied to the wire in order to hear if anyone was tampering with the obstacle at night.  We would add tanglefoot obstacles in front of our concertina, so that before they ever approached the main obstacle, the enemy would need to tiptoe through another obstacle.  If we had a long drive coming up to the house, we would emplace concrete jersey barriers, so that any vehicle would have to serpentine through the barriers toward the house without being able to accelerate.  Depending on the situation, threat, and terrain, there are numerous layers of defense which you may add to harden a position and make it very unpleasant for anyone attempting to harm those you care about.

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This page contains a single entry by Jim Rawles published on September 5, 2012 12:43 AM.

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