According to this news item, a US soldier has invented a device to prevent anyone from hiding a bomb in a culvert.
It’s basically a cone of rebar.
I’m puzzled how this would work. Are all bombs too big to fit thru the openings in the rebar? What prevents someone from removing the cone? If it’s a small diameter culvert, a lot of the barrier would protrude. What prevents a bomber from putting a device near the open end (wouldn’t be hidden much, but wouldn’t it still be effective)?
And it looks like debris would eventually clog the opening in spite of claims to the contrary. I just don’t see how it would be practical.
The impression I get is that the cone is intended to be rammed into the culvert with significant force - enough that it will bend to fit, and then with some springiness it jams in the hole like a barb. This could easily jam in well enough that the only practical way of removing it would be to cut it up. I think it is made in a few sizes, but has a significant range of fit if driven in hard enough.
Its ability to stop things being passed into the hole would appear to come not from a single mesh of bars, but the 3D stacking of bars down the length of the cone. Individually the openings are quite large, but they would appear to be stacked up in a manner that makes it impossible to pass solid objects through. Perfect of you want water and general water born junk to flow through.
Placing a bomb at the opening of a culvert probably does very little other than make the opening bigger. It is the ability to get the IED directly under a vehicle that makes them deadly. You need to either penetrate the armour, or slam the vehicle so hard the occupants are injured inside an otherwise intact vehicle. Both need the IED to be directly adjacent the vehicle, not to one side in a position where the vast majority of the blast is directed harmlessly. To pierce the armour of a vehicle you need a shaped charge (part of the dismaying skills the insurgents have learnt). These are not simple dumb bombs, but require exact placement and directing for the penetrating gas to do its work. Bombs in culverts probably are big dumb bombs that simply slam a vehicle. They would need to be directly underneath.
If you put a screen across a culvert, eventually it’s going to clog, especially as I doubt there’s anything like culvert maintenance over there. On the plus side, if it’s a desert-type region, I suspect there’s a lower potential for debris to do the clogging.
If it sees widespread use, it’ll be a great recruiting tool for the Taliban. The thing will clog up and cause a flood, ruining a farmer’s crops or washing his house away. Now he has a good reason to hate America.
It’s a great piece of backyard engineering, but a really lousy tool.
Maybe so, but it’s not like US forces weren’t already putting grates over culvert openings; it’s just that prior to this invention, they were custom-made grates, fabricated on site as in this video.
Rebar is easy to cut with bolt cutters. If, you had at least 4’ long if not 6’ long bolt cutters, and, they were actually available in quantity as they will only be able to be used a few times. I happen to know this as my dad was building something with rebar and we moved from a pneumatic cutting disc to a bolt cutter as it was much faster. We ended up going through several of them as eventually the hardened steel jaws begin to chip and then crack and ultimately fail.
Also, another key to IEDs is that they are placed rapidly. As in, shortly before a known convoy is to pass by. There are plenty of incidents where an Iraqi vehicle passed by and then within 15 minutes a US vehicle passes by and gets hit. The IED was a pressure plate activated IED and was placed in that time frame. Also, the main roads are routinely screened for IEDs so once again, planting them overnight, is pointless. The old school method of waiting hours on end to plant and then detonate had relatively passed. Most are now deployed within that short mentioned time frame.
So, the purpose of that culvert cone is to deter the deployment if an IED. If someone wants to place an IED and sees that screen they will go elsewhere and not there. That’s the purpose. You could cut the rebar but then you’d have to obtain a working set of bolt-cutters, and in a country with poor infrastructure this might be harder than it seems, and of course, the time to cut them, place the IED properly, and run. Ultimately, you could get strategic and leave certain culverts open to attarct the IEDs and then investigate those.
it looks easy to clean. clogged debris is the least of your problems in a semi-arid environment. however, the squares are still too big. a bangalore torpedo can easily be inserted using a wooden pole.
