Schneier on Security
A blog covering security and security technology.
« Sniffing Passwords is Easy |
| Fraudulent Stock Transactions »
November 10, 2005
Military Uses for Silly String
I'm a former Marine I in Afghanistan. Silly string has served me well in Combat especially in looking for IADs, simply put, booby traps. When you spray the silly string in dark areas, especially when you doing house to house fighting. On many occasions the silly string has saved me and my men's lives.
When you spray the string it just spreads everywhere and when it sets it lays right on the wire. Even in a dark room the string stands out revealing the trip wire.
Posted on November 10, 2005 at 7:59 AM
• 45 Comments
To receive these entries once a month by e-mail, sign up for the Crypto-Gram Newsletter.
I've heard they've come up with uses for fake ice cubes with spiders inside too
Do tell...? I can't believe they are pulling pranks on the insurgents? :)
You'll forgive me Bruce, but this one sounds like the kind of thing I'd expect to find debunked in Snopes.
The ingenuity of the American soldier is amazing. One of the biggest reasons for our military successes throughout history has been the ability to improvise and overcome.
Silly string use to save lives is a perfect example.
Military uses for fake ice cubes with spiders inside: Psychowar.
Spread the rumour that when the ice melts the REALLY VISCIOUS poisonous spider comes out of suspended animation and is HUNGRY. Then toss a few cubes into suspicious rooms and see psyched- out people come running out of the room.
if I can make a deadly weapon out of a pencil (or hurt someone with a credit card) silly string can definitely be put to good use.
What I'm curious about is - what WERE they doing with it in their packs in the first place, out on the field...
Sounds ingenious, sure. But isn't it IED, not IAD?
"You'll forgive me Bruce, but this one sounds like the kind of thing I'd expect to find debunked in Snopes."
Has it been?
"What I'm curious about is - what WERE they doing with it in their packs in the first place, out on the field..."
Sure, they are military men, but they are still, by and large, teenagers and very young adults. A few pranks, some silly string "exercises", sound like a wonderful way to blow off some of the incredible pressures they encounter. And whether or not it gets debunked, it sounds like it would work. If they aren't using it yet, I bet they will now. Thanks, Bruce.
Let's just hope they aren't using the flammable type of silly string!
This is OT, but check out
Via that blog post, we learn that Ahmed Chalabi is a University of Chicago mathematics wiz who is capable of breaking US and Iranian cryptography:
"Hitchens then turned the subject back to Chalabi, his good friend. I asked him if he thought Chalabi had been passing American intelligence to the Iranians. 'No,' he insisted. 'It's possible that with his training, you know, at [The University of] Chicago that with his own ability he was able to crack the codes. He is a mathematical genius. His expertise is cryptology. It is possible that he broke the codes himself.'"
Tripwires can be damned sensitive. Something that light might work.
I have to teach a class in January on IED, so I'll arrange to have some put together, and see what the string does.
I'll try to remember to send the results to Bruce.
Don't forget to tell Rob Cockerham about it too.
Someone set us up the bomb. Send every silly string for great justice.
There are special tools to detect/defuse bombs, tripwires, etc. but carrying all that stuff is insane. The silly string does make sense. You can shoot it for a long distance and it is fairly light. Even if the string set off a bomb, hopefully you'd be far enough away.
IAD=Improvised Anti-personnel Device? Most likely a typo.
I remember a British television program from several years ago (1990's sometime) which was obviously aimed at glorifying the British armed forces. Squads of four or five men from various regiments were picked to go through some set exercises. The tasks included forced marches, carrying an "injured" person crossing obstacles like ravines and so on.... sort of a military survivor. The one task that sticks in my mind was "clearing a mine field" or something similar. The Ghurka team started out by spraying silly string over the area to show up any tripwires and it was very effective. The silly string hung on the tripwire and showed where it was, but was light enough not to pull on it.
Given that this was a "trick" used by this team over ten years ago, I am not surprised to hear that other people are using the same technique now. The British armed forces have learned a lot about IED from their time in Northern Ireland.
It might be fun to spray that thing around but probably less fun to clean it off.
From my (limited) training with IED and explosives while in the armed forces it sounds like it could work.
However, it also sounds like something no sane armed force would recommend the soldiers to do. IED, especially those made by unskilled enemies, can be extremely sensitive. You learn to, if possible, not even walk heavily nearby as vibrations might set them off. Even if the string might be light, touching the trigger of such a device is not a safe bet under any circumstances.
Another problem is that people unskilled with explosives tend to err on the side of caution when it comes to the amount of explosives they use in the trap. Which means, they use so much that they are sure they blow up the enemy. I don’t know about Iraq or Afghanistan, but I remember reading that the average booby trap (not made of hand grenades) found in Vietnam was 10 kg of explosives, with some extreme cases containing several tons. Often they were build out of artillery shells, and I doubt you can “shoot��? that string long enough to survive a 155mm shell going off.
The combination means that anybody using such a trick to find booby-traps is most likely placing himself and his group in a grave danger (as if a war wasn’t dangerous enough). The old tricks (a lamp, attention and carefulness) are probably less likely to get you blown to bits.
Sounds like a great idea to me if it works. Cheap, light, and effective.
Maybe the manufacturers are actually pushing it on soldiers in order to find a new market overseas, since Silly String is apparently being banned domestically:
"In the second year of the crackdown, red and white 'Silly String Prohibited' signs have gone up along Hollywood Boulevard, spelling out the law and warning of a $1,000 fine for violators. Some passers-by have looked at them with confusion. [...] Across the country, from the Boston suburbs to Tacoma, Wash., the party favorite-menace has been banned, like beach balls have been, at graduation ceremonies, parades and festivals."
"However, it also sounds like something no sane armed force would recommend the soldiers to do."
Generally it may not be a good idea, but if you have to go into the building and can't wait for a demo team to secure it, it may be a life-saver.
Then again, it may also alert anyone inside of your presence outside the door.
Cockeyed is a very amusing site. Among other things, on the page
they have determined that a can of Silly String (hereinafter "SS") produces about 1,600 feet of "string" per 3.5 ounce can. In modern units, that is about 200 milligrams per metre. A housefly weighs about 1 gram, or as much as 5 _metres_ of SS. This stuff is _very_ light!
While one could, in principle, make a tripwire so sensitive that it was set off by SS, it would also be set off by flies landing on it, trucks driving past a considerable distance away, and probably even the vibrations from the operator's own footsteps as he backed away after setting it. In short, an IED with a tripwire so sensitive it was set off by SS would also be very unlikely to kill anyone except the fool who set it up, and maybe some hapless insects. Most actual real world tripwire operated fuzes have a fixed (but imprecise) operating tension which is somewhere between 1 and 2 kg-force. For example the US M16A1 requires a pull of about 1.5 kgf, while the Russian POMZ (which has been widely copied, and has a fuze also commonly used in IED) requires about 1 kg. 
I think this is a good idea, and I like it. I see just two issues:
a) Tripwires in a darkened room don't have to be at ankle height, so make sure you spray the SS up high and let it settle down low.
b) IEDs can be set off in quite a few ways other than tripwires strung across a room, and having all that SS draped around the room might distract the soldier from other signs. So I'd only use it last thing before actually entering, or if I didn't have time to do anything else.
As a small aside, one of the issues when clearing a complex area of IED is clearly indicating which areas have and have not been cleared. IF you only do the SS last, then presence of SS (but no mine marker!) => checked!
Finally it occurs to me that spraying an area with a particular colour of SS might make a cheap temporary way of ensuring that no-one has entered, which can be useful when, for example, searching a place and you don't have enough people to guard every room you've checked already. If the SS over the door is intact, then it's unlikely anyone has re-entered. Of course this would only be useful for a few minutes.
Note 1: This is the tension along the wire, which is not the same as the force pulling down on it. In fact if a slack wire forms an angle of q with the direct line between its endpoints, then a perpendicular force of F in its centre induces a tension of F / 2sin(q), which for small q can be quite a lot higher than F. However, for small q, a displacement of the wire also induces very little movement in the wire's endpoints (i.e., the firing pin). In fact if the wire is L in length, and the displacement is d, then d = L(1/cos(q) -1)/2 ~= L sin^2(q) / 4 = L F^2/16T^2
So if we assume a firing pin must be moved, say, 1 cm in order to fire the device (probably reasonable), and an indoor tripwire is unlikely to be more than 3 m long, then F/T is about 0.23, i.e. a fuze requiring a tension of 1.5 kg will require a weight in the middle of the wire of at least 350 grams. Still far too much for SS; that's equivalent to about a mile of SS.
presumably, now that silly string is an official part of the military arsenal three things will happen:
1. All use will be classified and reporting it will carry a mandatory life sentence
2. There will be a government commission set up to determine the most suitable colour
3. The price will increase from £1.00 a can to £500 a can
But doesn't it ruin the carpet?
"2. There will be a government commission set up to determine the most suitable colour"
It's military, so it has to be green!
"3. The price will increase from £1.00 a can to £500 a can"
If NASA wants to use it too the price will go up to $10,000 a can.
Sent this article to my nephew, who is a team leader for an Army EOD unit. He says it's an old technique and he's been carrying a can of silly string on his vest for years.
FWIW, Snopes has, as of yet, no mention at all of SS.
Imagine if you were a terrorist hiding in the back, waiting with an AK-47 for US soldiers to come in, what you would think when instead silly string came flying into the room.
There's considerable discussion here about what kind of tripwires and how much explosives are in an IED and how IAD was a typo. But the article didn't mention explosives, just booby-traps. If they're inspecting homes for terrorists they're more likely to run into home-brew booby-traps than explosives. It's pretty easy to rig a lethal booby trap with stuff you'd find around most homes. Why buy and deal with the logistics of C-4 when a bottle of ammonia and beach or an ironing board nailed to the ceiling and spring-loaded with the kitchen knives will do?
Here is a reply from a friend who is a Marine.
I wouldn't really be surpised, but I don't believe it. You can only carry so much and I'm not sure that you want your mind thinking to quickly draw out your silly string when you kick in a door and start doing room clearing. Grenades work pretty well at detecting (that is, setting off) booby traps and grenades have the added bonus of (at least) disorienting the bad guys if they go off anywhere near them. Silly string sounds like a neat idea for guys who are dealing with booby-traps, but no real threat to life--like playing paintball or laser tag in an urban setting.
For whatever reason... this article has been "modified by request" - it now reads simply, "It stops tanks."
Go to Google's cache to read the original: http://188.8.131.52/search?...
All this discussion about whether the military uses silly string or not. Who do you think invented it? The original mix came in 16oz cans and was called "wire detector" There were no party colors, it was all white for best visibility in all light conditions. Originally developed in Korea for detecting trip wired in mine fields it had limited use in Vietnam where humidity kept it from sticking to anything. Not carried by most US forces, they can only carry so much and the supply is limited, it is usually used by units dedicated to clearing mines and IEDs.
I SALE THIS PROD.
IF ANY INTEREST
what about putting pigs blood on bullets
I understand that this also helps too.
the enemy can't meet their maker.
if they come in contact with pigs blood.
it helps to let them your diong it.
the british did it years ago. it cut down
Duh, it works. Florescent + night vision = easily detectable wires..
think about it...
I'm a mom in Ga that's just concern about helping our troops who do I contact as far as sending the silly string to ? my e-mail is firstname.lastname@example.org
my name is anthony Luciani, i am a sophmore from raligh north carolina. I am in boy scout troop 215, and i am working on gettin my rank of eagle scout. But i am in need of a eagle project. If it is okay with you and your troops in Iraq i would like to make my project to collect alot of silly string and send it to you in Iraq. Please email me at email@example.com if you are interesting in this at all
our elementry school collected over 300 cans of silly string...a woman from new jersery has a son over in iraq..she was on good morning america and said what her son asked her for was silly string..so she started collecting it..the last i had heard she has over 2000 cans and climbing..so the myth about the silly string is true..our soliders use other everyday items as well when in the field..the place condoms over the barrel of their gun so sand wont get in it..they use women feminine products to pack wound..
I chair Missions Committee at my church. We are interested in sending Silly String cans to whoever can ship them to Iraq. Pls. send info asap as we have a meeting in two weeks. Thank You
My husband is a MP in the D.C. Army National Guard. His unit is being sent over to Iraq in May. I am very interested in collecting silly string. I am curious about who I can contact about sending the string over to Iraq. Please contact me at firstname.lastname@example.org. Thank you.
there should be a different type of silly string for the military. i got caught and suspended for 3 months todai for possesion of silly string. because of its use im basically carrying a "weapon" and since i sprayed it i had and used a weapon in school.
i love you americans :) you all love your war dont you. :)
I think the manufacturer should make a standardised military can of silly string with a camo shell and then a flourescing string so it is even more visible in dark places or at night. I've tried to contact a manufacturer to suggest this, but I can't seem to find one. Maybe a standard military issued of silly string(more like serious string now) will save more lives. At least the camo shell wouldn't be as visible on their person when they carry it.
You can't send it by airmail because it's an areosol can. Maybe the army/airforce could help you though.
4500 people died from diarrhea yesterday (and every day), and we turn out in droves for silly string.
Schneier.com is a personal website. Opinions expressed are not necessarily those of BT.