We used two kinds: 1. Those that were very sensitive to temperature and pressure; 2. Those that you could throw into a fire. Knowing which was which and what was what made one less a "panic chicken" when confronted with a sample to use. At OCS, it made for a saner existence and a calmer teaching environment.
Probably the most notorious explosive of them all had to be this electric detonator that came in a small aluminum tube with two long trailing electrical wires attached (usually in yellow and white). Most folks were fearful of handling EDs and who could blame them! They were easily induced with electrical energy by stray radio waves and explode. You see, a detonator is very simply a small explosive charge that sets off a larger one. And often, a VERY MUCH BIGGER ONE!. This is because explosives are like chronically lazy people who needs a kick up their backsides to get them going. And like a party balloon exploding, they would wake up with a pop. Like Austin Powers might say, "It's shockwave, baby!"
Basically, in the world of explosives, there are two types of detonators: Electric (ED) and non-electric (NED). The difference lay in how you want to set it off. The detonator themselves are of the same construct. If you slice one open (just imagine it, don't do it), it consists of a high explosive (HE) element at the far end, some intermediate explosive in the middle, and some fire-sensitive explosive at the near end. Sometimes the middle bit is skipped and only two composite compounds are used. And the reason for having a fire-sensitive end is so it can be activated by a burning fuse (which is nothing but gun powder or cordite wrapped up in water-proof paper). Often, this sensitive compound of the detonator is cued to pressure as well, so it is not good to go stomping on one! Or even attempt to push one into a plastic explosive like they always do in the movies. The friction can cause heat and make the detonator explode. We were taught to always use a pen or finger to make a hole first!)
In EDs, the means of firing is an electronic fuse, not a match-lit one. Think of a bulb filament being afixed inside a non-electronic detonator. When that filament glows, kaboom! So when carrying EDs around, it is never a good idea for the two wire leads (one +ve, the other -ve) to be picking up stray electromagnetic inductions. The detonator bit may be small (usually the size of an AA battery and half as thin) but it is after all an HE charge. Even if you don't die, a large part of you will be pulverized. I don't recommend it even if it is to tenderise meat. And high explosives have a particularly noxious smell.
To prevent EDs from accidentally catching, the thing to do is twist their end strands together. In this way, eddy currents (i.e. induced electric currents) will be shorted out and not circulate. You live to blow something else up another day!
One demonstration we liked to show the cadets during the lesson on detonators was called The Helmet Show. It was to emphasize how powerful a small detonator can be. We would fire off an NED under a steel helmet (the good ol' SAF steel helmet). A loud boom would result sending the helmet flying some 4m into the air. It's quite the spectacular sight and cadets would ooh and aah. They then quickly suck in breath when the helmet lands with a mighty thud in front of them.
I went through the same experience as a cadet myself. It gave me renewed respect for explosives, especially seeing how that powerful NED is not much bigger than our little pinky!
After the show, the cadets would then be required to practice crimping a detonator to a safety fuse. Although dummy detonators were used, some of the cadets still shivered with fear. It's true, if you had crimped too high on the sensitive part of the detonator it would blow up in your face. But with dummies, there was really nothing to worry about. (Well, unless you are the sort of clumsy clod who can even cut off a finger while trimming nails...then, God-bless. You know, it's kind of impossible!)
However, we instructors were extra merciless with those "scaredy" cadets. We would drum into them the need to be discerning. No cadet graduated from my class (or any of my instructor's) as a Panic Chicken nor Cocky Bastard. Handling explosives require knowledge, care and respect. If you are short on one attribute, your time on this Earth could be severely limited. And on critical missions, I just cannot have an officer be unsure of handling what I find to be a powerful and useful weapon.
Back then, cadets in OCS had always been taught explosives during their Demolition lessons; they learnt the various kinds of charges and how to use them to blow up obstacles and booby traps. They would then carry this knowledge with them when they graduate as officers. But how much they remember or is confident of executing any demolition work is up to anyone's guess. Often, they only reprise this knowledge when setting up simulation charges for use during 'realistic' training exercises. At the time, a common explosive charge for this purpose was Ammunol (my spelling), a cylindrical thing sized between a condensed milk tin and a Milo one. It was more for sound effect than actual destruction although the hole it did make was rather large. Hey, it is still made up of TNT flakes loosely packed into a plastic container! An HE charge no less. Also, explosives in flake form can still do extensive damage. We used to pack a sack of it and place it at the base of a slope to send to blow a three tonner over (what is now known as road side incendiaries or IEDs (Iraq War-speak)).
As head of Demo Team, I always wondered how much explosive knowledge my cadets would retain after graduating as officers. If they were my students, I could make a guess. But for cadets/officers prior to my time, I had no inkling. If officers forget, they could simply refer to a handbook on the subject. It was the same anyway in the world's military.
One day, the thing we feared most happened. An officer and a couple of cadets were seriously injured during a routine training exercise. A simulation explosive circuit they had set up went off before it was fully put in place.
It killed a cadet instantly and wounded another; I think he lost an arm. The officer in charge (someone I didn't train and who was about to ROD) lost a number of fingers and had a side of his body burnt. Scant consolation for him.
As usual, a BOI - board of inquiry - was formed. My school head then, a Major Tan, called me into his office to better understand what could have happened. He gave me some details and asked for my opinion. From what he told me, it was an obvious case of premature detonation. That event in itself is not surprising. Electric thunderstorms have been known to set off detonators by accident. I remember reading a Vietnam War case of how claymore mines - an electrically fired anti-personnel mine - would set themselves off when surrounded by electrostatic air. And thunderstorms were then known to even set off road mines by direct lightning strikes.
But it was how the cadets and officer were injured that told me how the accident might have happened.
There is a sequence when it comes to laying out an explosive circuit. First, you need a trigger. Second, a detonator. Third, if the distance to the charge is long, a conducting det-cord is required. Fourth, the charge itself. It is quite straight forward on paper and it doesn't matter if it is an electrical or non-electrical setup - they all follow the same schema.
However, the actual work is quite different: There is only one sequence to doing it right. You start with the main charge and work backwards. You don't ever mix the more sensitive smaller charges (detonators) with the less sensitive bigger ones (a main charge like Ammunol) until you are ready to do so. (There's an operational imperative for putting the main charge in position first, but I let you figure that out for yourself.)
However, some soldiers (the commandos?) like to take the short-cut and lay everything out at the same time, i.e. have someone connect up the main charge while someone else is fixing up the trigger device. Another guy would be laying down the det-cord. It is like having three persons clean a rifle when it is fully loaded and cocked.
I know many elect to do it this way just to save time. This is especially so when the simulation circuit is large (trying to simulate multiple bombings) and the exercise is at night and everybody wanting to finish early and go home. But it is a very dangerous stunt to contemplate. Only in very extreme circumstances (involving the Special Forces?) should it be done.
After it became apparent to me what went wrong, I suggested to the CI that perhaps the next time, if ever a company was uncertain about Demolition matters, they should just contact my team right away. We would be most happy to do it for them.
Well, a few weeks later, when the use-of-explosives-in-training embargo was lifted, my suggestion to the CI became de facto. Henceforth, all simulation circuits would be designed and laid out by the Demo Team. My team partner Fong and I were only too glad to take on that extra responsibility, which would mean more nights out with the cadets at their training locations. Fong and I would not have it any other way. Something mortally bad had already happened, it made no sense to let it happen again either by chance, by force majeur (unpredictable weather) or even simple human error. In any case, the company commanders and their Mentor instructors themselves were really grateful and would treat us Demo Team members very well, even fetching us food and making sure we always had a spot at their GS dining table. (Fong and I used to joke: "Here goes our last meal!")
The CI never shared with me what the BOI found. They always never do. I did meet up with the injured officer after he was discharged from hospital. Besides losing some fingers, his hearing and sight were also affected. He was one of the better Mentor instructors so I felt bad for him. I just hoped that his emotional scars would heal just as quickly as his physical wounds.
From that time on, OCS never suffered anymore cases of injury from explosives used in training. We had removed an uncertain factor in one of its application in the school.
High explosives are powerful but they can be tamed. Just don't "play-play". Even explosives kept long in storage can behave in unpredictable ways. An example is the hand grenade. But that's another story.
(Note: If you were a cadet in OCS before, a confession for you: We actually used two detonators instead of one in The Helmet Show. It's more spectacular and you must admit, it worked! It does leave a deeper impression. This was something of a legacy practice in Demo teaching and the Team passed it on from one batch of instructors to the next . ;-) Related story: Dead Cadet
This is one of the most interesting NS stories I've come across. Nice one, TC.
ReplyDeleteThanks, Ivan. :-)
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