Letter Re: Anti-Vehicular Barriers for Retreat Security

Dear Jim,
I have for some time been meaning to write about vehicular and other counter-mobility obstacles. The dramatic video that you posted yesterday has prompted me.

Ever since reading “Patriots”, when the looters simply cut the lock on the front gate with a “universal key” (bolt cutters), it has been on my mind. Coming as I do from a combat engineer background, I couldn’t believe how they could have overlooked such as basic aspect of perimeter hardening. They could have very well lost that fight because some clown had the sense to bring a pair of bolt cutters along.

In terms of retreat security, counter-mobility, from both an anti-personnel and anti-vehicular aspect, must be a high priority. In your profiles of retreat people you know, I noticed that only one–the Vietnam veteran–had laid in a heavy stockpile of barbed wire. He obviously has some experience with this.

It must be stated from the onset that barriers of any kind are intended only to delay and channel aggressors, rarely will they stop them outright. Given preparation, planning, time and determination, any barrier can be breached. In a survival situation, however, this adds up to, “How bad do you want in here?” This is where the delay and channel aspects can turn into a painful experience and aggressors are forced to choose between paying dearly for entrance or picking a softer target. And that’s what we’re looking for.

From there, in terms of counter mobility, there are thus two categories…anti-vehicular and anti-personnel. As one may expect, one set is designed for cars and such and the other for humans on foot. We deal here with the vehicles.

In the anti-vehicular category there are two sub-categories; above and below ground. The below ground category consists of obstacles such as ditches, pit falls and craters (or mines if you take it all the way).
These are deliberately created, or in some cases simply improved, terrain features that prevent vehicles from moving across with ease. For example, a deep ditch with steep walls prevents easy transverse because the vehicle falls in nose first and gets stuck, unable to rear up and clear the opposite side. These sorts of obstacles have to be bridged in order to be crossed. It is unlikely in a TEOTWAWKIscenario that the looters will be bringing along bridging sections, so if time and resources permit, such features can be used to deny easy access from road frontage. If you have access to a loader of some kind, they’re not to difficult to dig (given the right ground) and when the grass grows over them they don’t appear as militant as a chain link fence. Existing ditches can be modified to achieve the sheer wall on the side facing your main line of resistance (MLR).

Such obstacles can also be installed on roads at choke points. Here is where the obstacle isn’t a ditch line running for 3?4 of a mile along your road, but a single point on a road or your driveway where the trees get in tight, for example. In the West in particular, cattle guards are outstanding. In normal times the grate stays down, when it’s time to close the road, the grate comes up. Unless they’ve brought a monster truck along, getting across one of these dug out to four feet deep is going to be an axel breaking, hood crunching proposition. (I remember well a midnight encounter with an irrigation ditch in NM that had quite the same effect)

There are several drawbacks to these features, however. First, if they are permanent and outsiders can’t get across, neither can you…unless you have your own bridging apparatus planned and on hand or permanent crossing points, such as your driveway culvert. (The classic draw bridge/cattle guard is such an example)
Second, without accompanying anti-personnel obstacles and being well covered, they make good cover for anyone dismounted, being that they are essentially a trench. But, if far enough away from your main line of resistance, with a good bit of open ground (and maybe some anti-personnel stuff between the ditch and you) they can at least prevent a mounted attack coming in at speed right to your doorstep.

Then there are the above ground types of anti-vehicular obstacle. The concrete barrier is by the far the most common type in use here in the US . As we saw on the video, they posses impressive stopping power. (They are, however, permanent and provide cover)

Another kind is the “Bollard” type. These are simply solid posts of various materials ranging from wood to cast iron (or old cannon barrels in some places) that are dug into the ground or set down into receptacles in the ground and locked. We see these in use to deny sidewalk parking or restrict access to service roads that are in frequent use. Sometimes they are reinforced with heavy rope or chain running between them, especially if they run for any distance. Unlike a concrete barrier, they can easily be passed off as a “decorative” feature. If they happen to be made from something along the lines of railroad ties with 1in cable running between them, they become something a bit more. Even railroad rails or I beams, cut to length and placed so that a vehicle cannot squeeze through them will generally stop anything this side of a tracked armored vehicle. The real beauty of bollards is that they can be emplaced as needed, usually across choke points, and pulled up and stashed when not needed if engineered for it.

A more permanent type was seen in Britain where invasion preparations featured concrete cubes or cylinders set like the classic WWII dragon’s teeth. There were also the classic I-beam “hedgehogs” where beams were welded together in a crossing pattern and then secured in some manner to the ground.

Then there are good old fashioned gates. As we saw in “Patriots”, a gate is only as strong as whatever is locking it closed. As they are also dependent on hinges generally, if the post goes, so does the gate. Only the most robust structures of this type will stop vehicles generally.

There is one other kind, however, that was employed all over southern Britain in preparation for the expected German landings. These were gates of a sort, but instead of having the opening and closing feature, they were simply two very heavy colonnades of stone and concrete on each side of the road with slots left in them for inserting railroad rails or I-beams when the time came.

A good cross section of these pre-invasion obstacles set out in southern Britain can be seen at this web site. Typically British, they were usually unobtrusive, which may also be a boon for retreats wishing to avoid the “Nut case survivalist” label too soon into the game.

In any case, anti-vehicular counter mobility obstacles should be part of any survivalist retreat plan. Be they professional looking “Driveway” bollards or simply trees knocked down across the road [an “abatis”] when the time comes, they prevent looters from roaring up to your doorstep and bailing out guns ablaze. Even a strategically planted line of fast maturing trees will have the desired effect.

Surfing around online a bit will give all sorts of good ideas, as will a copy of the [U.S. Arm]y Engineer Field Data manual, FM 5-34.

In any case, the inventive will come up with any number of ways to block roads when sticking to the two main categories; above and below ground obstacles. But always remember, obstacles are not intended to stop an advancing aggressor in their tracks. They are intended to slow them down or channel them into kill zones of your choosing. Essentially, with anti-vehicular emplacements, the best idea is to turn a mounted, 40 m.p.h. advance in a steel chassis into a dismounted, 8 m.p.h. advance behind a cotton shirt.(Or, at the very least a 10m.p.h. advance as they slow down to try and get past all this crazy junk in the road, at which point their 8 cylinder engine starts becoming a 9, 10, 11, 12 cylinder because of the 30-06 AP that’s ventilating the engine block.)

At that point, your adversary may just decide that attacking you is a bit too pricey and move on.

P.S.: if any of you haven’t read “Patriots” yet, do so. Then read it again…and take technical notes. I recommend tabbing a notebook into relevant categories such as food, firepower, communications, fortification, etc. Jim’s novel is a field manual in it’s own right. – Mosby