[Basic] Skill of the week: Explosives
 

Explosives is the IQ/A skill of working with explosive and incendiary materials. It has several specialisations: (Demolition), for blowing stuff up; (Explosive Ordnance Disposal), for making explosives safe; (Fireworks), for making pyrotechnic devices; (Nuclear Ordnance Disposal), for making nuclear devices safe, and (Underwater Demolition), for doing (Demolition) underwater. All of these were separate skills under 3e, and drawing them together is a good example of the ways that skills changed at 4e. Most of the skills default to each other at -4, but the two kinds of Disposal default to each other at -2, and (Demolitions) and (Underwater Demolitions) do the same. (Demolition) defaults to Engineer (Mining) or (Combat) at -3, with reverse defaults at -6 and (Fireworks) defaults to Chemistry -3.

Explosives skills are not something you want to do hurriedly or carelessly: modifiers include -1 to -5 for distractions, Time Spent (B346), and equipment modifiers. Some disadvantages also seem contra-indicated to me, notably Klutz and Overconfidence. The prerequisite of DX12 or better for (EOD) (and presumably (NOD)) is a bit strange as a hard requirement, and seems to the only case of a skill with a basic attribute prerequisite in Basic. Saying that the military and police forces that do most (EOD) training normally demand above-average DX in candidates might make more sense, in much the same way as the description of (Underwater Demolition) says that you usually need Swimming or Scuba skill to make use of UD. The Flexibility advantage is also useful for getting into places where explosives need to go, or be removed. And Luck is valuable when dealing with things that Are Not Your Friend.

If you have Explosives skill, it's wise to have it at a decent level, and to try to get all the bonuses you can manage. Failures are always risky, and (EOD) is downright dangerous, given that you need to win a QC against the maker of the device you're trying to disarm.

Explosives is (mostly) a Use skill in the Design/Repair/Use triad scheme. Quite a few Engineer specialisations include designing applications of explosives, but there doesn't seem to be a Repair skill: fixing damaged explosive systems may well be considered too dangerous. Creating new kinds of explosive is Chemistry, and manufacturing them is chemical-plant operation.

Explosive traps are set with (Demolitions) at -2, rather than Traps skill, and that penalty can be bought off with the Set Trap technique. Basic also points out that the Work by Touch technique can be bought for Explosives specialisations.

Rules for explosions and blowing stuff up are on B414-415, and are expanded on P181-189 of High-Tech. Low-Tech covers TL3-4 explosives and incendiaries, which demand care and respect, on P84-87. Tactical Shooting adds improvised explosive devices, and Ultra-Tech covers science-fictional explosives and supporting equipment, although I'm terrified by the low price of antimatter at TL12, even if it is LC0. Underground Adventures has non-combat explosives applications, in tunnelling and seismology.

Explosives skills are fairly common on templates for high-tech characters, with (Demolition) being the most common. Action naturally has a lot about Explosives, too much to summarise. High-Tech has more details of equipment, throughout the book. Monster Hunters has less explosive detail than Action, but it should be easy to apply the Action rules if required. Surprisingly, there are no Talents in PU3 that include Explosives, although there are several applicable wildcards in PU7. PU1, Powers and Chinese Elemental Powers cover using powers with Explosives skills. Space adds (Nuclear Demolition) specialisation, and Zombies warns of the drawbacks of blowing up contagious enemies.

I've seen (Demolition) used a lot, by the Demolition Woman in our Action/Reign of Steel game, and done a bit myself, feeding ten pounds of time-fused RDX to the Great Worm of Bethnal Green in a WWII campaign. EOD has so far been left to NPC specialists, and my Elizabethan character with (Fireworks) never got to use it.

How have you exploded a scenario, or defused one?

Re: [Basic] Skill of the week: Explosives
 

Explosives somewhat grabs the full trinity. It (specifically the Demolitions specialization) is the skill to use to design and assemble charges for a specific purpose, as well as to place them. It's as good as Chemistry and better than any other skill for most cases of cooking explosive compounds in the first place.

I'd say that repairing explosives as such is mostly impossible...you could attach a new detonator to a charge that no longer detonates normally, and you can certainly disassemble an unsatisfactory explosive (using EOD) and re-use the materials in a new charge, but what would it even mean to repair one?

Repairing, designing, and building nuclear weapons is another, much more complex matter. High Tech pretty much dismisses the topic, outside a cinematic special case (which it allocates to Engineer (Nuclear)), and I don't know if any other sources really address that. It does seem that there should be a viable technician skill for maintaining nuclear warheads, which are rather sophisticated objects and do have potentially user-serviceable parts inside.

Re: [Basic] Skill of the week: Explosives
 

That would be Armoury (Heavy Weapons). Though demanding a unique new specialization wouldn't be ridiculous either.

And it's not unreasonable to allow somebody with Engineer (Nuclear) and Explosives (Demolitions) to design a nuclear weapon even in a realistic setting. It's the *building* part that's hard, between the difficulty of obtaining fissionables, their toxicity, and getting the necessary high precision out of something as inherently inexact as *explosions* to drive the parts together hard enough they'll go bomb critical rather than melt or release just enough energy to blow the pieces back apart.

Hm, now that I consider it, if you didn't care about the nuclear weapon being *portable*, I wonder if it might be easier to build a mechanical system of assembling the parts really fast? There may be a mad genius super-villain plot in there involving somebody "redeveloping" a old city center rail yard with apparently purposeless catapults and giant rotary slings.....

Re: [Basic] Skill of the week: Explosives
 

Back in the day, in a Caribbean pirates campaign, I played the ship's master gunner, Fornication Jones ("Me da named me 'Fly-Fornication Jones,' him being a Puritan, but while I was in the army the 'Fly' dropped off"). There was an episode when we were being pursued by a rival pirate ship whose captain was notoriously ruthless. Jones combined his Explosives (Pyrotechnics) and Mechanic (Clockwork) skill to prepare two casks full of powder timed to go off at a set interval after we dropped them over the stern. Thanks to a critical success on one of the rolls, they set off the other ship's magazine. . . .

Re: [Basic] Skill of the week: Explosives
 

You don't have to be all that mad. It has to be a gun-assembly device, with no compression. That means using U235 rather than plutonium, and U235's low spontaneous fission rate means the assembly doesn't have to be terribly fast. Big springs will do. Some LARPers once asked me to work up a concept for a nuclear device to work in a world where explosives didn't work. Steam did, though: heat up a boiler to a nice high pressure and have it rupture a diaphragm.

Re: [Basic] Skill of the week: Explosives
 

Yeah, you're clearly right there. And I would be strongly inclined to rapidly complicate the Armory landscape if I were left to my own devices and ignoring the little reminder that nearly nobody cares about realistic divisions in technical skills.

Re: [Basic] Skill of the week: Explosives
 

Well that's terrifying. I had no idea you could generate the necessary compression without resorting to explosives. I suppose a boiler could do it not that you say it: I've heard of cold seawater hitting a boiler destroying a steamship from the reaction.

Re: [Basic] Skill of the week: Explosives
 

Compression is not actually necessary. Critical mass depends on density, so compression is a good idea, and economises on the expensive fissionable material, but it's not required.

The tricky bit with assembling a critical mass is doing it fast enough. You want to achieve rather more than a critical mass, or the reaction stops very quickly as it expands (at the relevant pressures and temperatures, the physical strength of the materials is utterly irrelevant, and the only thing limiting expansion is inertia).

Plutonium has a fairly high rate of spontaneous fission, so if it is assembled slowly, the reaction tends to start before assembly is complete, and you get a "fizzle". The only practical way to assemble it is at the very high speeds of an implosion.

U235 has a much lower spontaneous fission rate, and taking a few hundredths of a second to assemble it is no problem.

There's no real need to worry about this. Building a practical implosion system is much easier than making plutonium or U235. Every nation-state that has carried through a nuclear weapons program seems to have succeeded on their first attempt. Controlling the manufacture and storage of those materials is the main thing done to limit access to nuclear weapons.

That seems to be because cold water hitting a boiler will cool the metal of the boiler rapidly, which is likely to cause it to crack. At which point it bursts, releasing all its steam.

Re: [Basic] Skill of the week: Explosives
 

As anyone who's played games with me will know, I tend to use this skill quite a bit as a player and expect it of PCs when I'm GMing, so it shows up a great deal in my character archive. I have at least once dropped Nuclear Ordnance Disposal on a pre-gen character sheet purely to see the player's face when he realises what he might be expected to do. (And yes, there is an opportunity for him to use it in the scenario.)

Re: [Basic] Skill of the week: Explosives
 

You could literally make a nuclear explosion by hand, by taking two large subcritical masses and fitting them together. (EDIT: Or would that be an underpowered (but catastrophic nonetheless) fizzle because the fissionables of the core would burn out over a slightly longer time than if it was slammed together mechanically?)

Obviously not a survivable exercise.

Re: [Basic] Skill of the week: Explosives
 

Maybe. The popular image of two hemispheres with their flat faces slammed together is not how it is done, because heating of the air between them will separate them very quickly.

Actual gun-assembly U235 devices put a cylindrical sleeve over a rod, or other configurations where heating of air doesn't strongly disassemble them. You might manage to assemble one of those by hand before it went off, if you didn't have a neutron source around: those are normally provided to initiate the reaction.

Re: [Basic] Skill of the week: Explosives
 

It's not so much that the reaction is slower that causes the fizzle as the geometry never gets to the right point. As the subcritical bits get closer together they heat up from the increasing fission rates. The trick to getting a nuclear explosion is to get them close enough together in a shape with a low enough surface area (from which neutrons are escaping) relative to their volume. In principle heated air might push apart colliding hemispheres, but you might not get even that far doing it by hand, because the pieces get hard to hold on to as they heat up, and once they melt (or *vaporize*) you can't push on them at all and it doesn't take much flow before the assembled mass isn't a sphere, and hence has more surface area that you planned for.

The suddenly generated cloud of metal plasma glowing in neutrons and x-rays will certainly kill you, and likely anybody else in the same building, but still is several orders of magnitude less destructive than if you had set it off properly.

Re: [Basic] Skill of the week: Explosives
 

They don't stay together long enough. I've read about a macho exercise called "twisting the dragon's tail" that physicists used to do during WWII involving lowering two subcritical masses together with a hand-held lever . . . at least in legend.

Re: [Basic] Skill of the week: Explosives
 

Oh, not just legend. Messing with near-criticalities was something that definitely happened, and killed a few physicists too.

I suspect the purpose of the lever there would be to let you carefully control how close you position the pieces, so as to let you approach fatal stupidity without actually quite committing it.

Re: [Basic] Skill of the week: Explosives
 

Beautiful. There is one aspect in which Hollywood reality is correct: warships, tanks, and other combat vehicles armed with artillery usually do carry enough explosive to destroy them, if it can be set off.

Re: [Basic] Skill of the week: Explosives
 

Although I would not think that a depth-charged wooden ship having its magazine explode is a likely outcome. As opposed to having it just break open and flood. Of course, as a critical result it doesn't need to be a likely outcome.

Caution is indicated --
 

Years ago I knew a guy who was a combat engineer in the National Guard. He told me two basic rules about explosives.

Rule 1: If you don't know what you are doing you will kill yourself.

Rule 2: Unless you've had professional training, and enough thereof, you don't know what you're doing.

So -- don't try this at home, sports fans.

Re: [Basic] Skill of the week: Explosives
 

What about the Unabomer? He was trained as a math professor, and managed to produce workable explosives for decades. He'd still be at it if his brother hadn't turned him in.

Re: [Basic] Skill of the week: Explosives
 

Generalizations like that are pretty much always false, but it's often a very bad idea to assume that you personally are one of the exceptions.


EDIT: That said, I know there are plenty of people around here who have played around with explosives without professional training and done fine. They mostly stick to lower end of the difficulty-and-danger scale and hopefully have non-professional training from people who've done it before, though.

Re: [Basic] Skill of the week: Explosives
 

Plus, judging by at least one that I talked to, there's a matter of self-training / study beginning with theory and moving on to practice.

I suspect the dangers of explosives are also routinely exaggerated in order to discourage people from trying. Kinda like the drug exaggerations of the . . . 80s, right?

Re: [Basic] Skill of the week: Explosives
 

Also probably an aspect of the safe firearm handling rules approach that overcautious is much better than an accident. When it comes to hazards that are both serious and not normalized, a 95% chance that nothing will go wrong tends to be considered appallingly reckless.

Re: [Basic] Skill of the week: Explosives
 

It comes down to this: how do you prefer to die? If you like accident or disease, there's a prescribed path for that. If you'd prefer to be killed by a hobby, there's options for that too.

Re: [Basic] Skill of the week: Explosives
 

I'll take "cooked in the heat death of the universe" thank you.

Re: [Basic] Skill of the week: Explosives
 

I'm friends with three EOD trained individuals. One of those individuals was an accident Investigator. While very rare accidents with explosives do happen. They are quite nasty when they do happen. Think chunky salsa.

All three of the EOD were Military trained and at least one of them had to deal with terrorist devices. It says volumes that among terrorist groups that blowing themselves up by accident is common even among the experienced ones.

Outside of those three I used to know a guy who ran with the Soldier of Fortune crowd back in the 1980s. He once saw a cowboy type keep blasting caps in a cigarette case. Said cowboy is now called stumpy as a static charge set off the caps while the guy was opening the case.

Then you have the idiots who pick up a copy of the "Anarchist Cookbook" or some other "Explosives manual" and then try and make their own explosives. I'm surprised that crickets* are as common as they are. Really anything not made by a trained professional out of industrial components is an accident waiting to happen.

*explosive filled C02 cartridges. A very easy way to lose fingers or a hand.

Re: [Basic] Skill of the week: Explosives
 

Look up the Demon Core ...

Re: [Basic] Skill of the week: Explosives
 

I many years ago saw a theoretical design for a gun type fission device that used a 3 story townhouse. Run a tube from attic to cellar, fill the cellar with sand/rubble/concrete to act as a tamper. Put one part of the bomb at the bottom of the tube, put the other part at the top with a heavy concrete weight on top of it, cut rope. You want good guide rails and a conical shape to the two pieces so they self align.

Re: [Basic] Skill of the week: Explosives
 

I really, really want to do this because it sounds AWESOME. I have to keep telling myself that it would be ridiculously fatal immediately.

Re: [Basic] Skill of the week: Explosives
 

Heat death refers to the break down / cessation of all matter and energy except a very tiny forever fading modicum of heat.
Still, I prefer to get squirted into a different younger universe long before then.

Re: [Basic] Skill of the week: Explosives
 

I'll make that choice when it comes. I may decide I'm done with life by then.

Re: [Basic] Skill of the week: Explosives
 

Well they have to try to deal with idiocy like this: people buying unexploded artillery shells dug up on WWI battlefields and trying to take them back to the UK through the Chanel Tunnel.

Re: [Basic] Skill of the week: Explosives
 

I don't think it will actually be that hot. Maybe a few kelvins. It's called heat death because there won't be any matter or energy left except the ambient warmth of waste heat from proton decay.

Re: [Basic] Skill of the week: Explosives
 

Suicide is always an option. I never understood why so many profess what amounts to a fear of living. That they always need an inevitable death.

I really want to live today, so why must X years in the future be any different?

Re: [Basic] Skill of the week: Explosives
 

People change.

I used to not expect to live past 30 and was decidedly set on dying by then. I missed that date due to changing tastes. Now I want to live forever, but I can see myself changing back given enough time or boredom.