Explosives (EOD) and DX 12+ Prerequisite

[Icelander]

I can't really see this DX minimum being necessary to learn the realistic skill of Explosives (EOD). The overwhelming number of uses will be IQ-based and aim to figure out a way to safely detonate ordnance or clear a minefield without endangering friendly troops.

Cinematic cutting of coloured wires with High Manual Dexterity (which, by the RAW, would apparently not matter when it comes to qualifying for being allowed to improve the Explosives (EOD) skill from default) represents far less than 1% of use cases.

Realistic EOD would be finding and marking the edges of a minefield, and, if it needs to be cleared, having the explosive ordnance disposal knowledge to know what kind of armoured bulldozer or tank could safely drive through to clear a path. Or having the ability to calculate that the mine you located with your skill might blow through your mine-clearing bulldozer and then knowing how thick an extra steel reinforcement needs to be welded to your vehicle before clearing the field.

Or rigging the minefield with explosives to clear it with sympathetic explosions. Shoot it with an AMR, rocket or grenade. Call in artillery on it. So on and so forth. If we combine all police or military EOD together, setting the bomb off from a distance, after clearing all civilians and/or friendlies, is probably the most common method.

If none of that is practical, mapping the minefield and noting down the fuzes, trigger systems, and how far off friendly troops need to be for safety, would be how military explosive ordnance disposal experts would deal with it.

This is all IQ-based, except the vital discovery of a mine or rigged explosive trap, which might be Per-based Traps or Explosives (EOD). Only a very rare and delicate technique, done only when there is no other alternative, requires DX at all.

So, why make DX 12+ a prerequisite for the skill as a whole, instead of just that technique?
And High Manual Dexteriy should definitively be able to substitute for DX here.

[johndallman]

Originally Posted by Icelander

So, why make DX 12+ a prerequisite for the skill as a whole, instead of just that technique?

Most of what you describe as realistic EOD is, I think, Engineer (Combat).

The DX 12 requirement is legacy from 3e. It could be claimed that armies would be fussy about who they taught EOD, and would avoid teaching it to people who weren't notably good with their hands, but that should be explicit, and HMD would definitely be usable.

[Icelander]

Originally Posted by johndallman

Most of what you describe as realistic EOD is, I think, Engineer (Combat).

The officers of whichever company of the Engineer Combat Battalion attached to the division is preceding the advance are using Engineer (Combat). The enlisted combat engineers crawling in the mud locating the limits of the mine field by finding mines with their knives are using a skill they didn't need to go to college for Mathematics (Applied) to learn, their skills are blue-collar and get their uniforms dirty, even when they are IQ-based. Some of the enlisted men are using Driving (Construction Equipment), but the history of US Army Combat Engineering units in the Korean War I'm reading has them spend a lot of time in the dirt probing for mines with knives. That's not Engineering, that's directly interacting with the explosive ordnance that you are disposing off.

For that matter, during those times when they were not in a hurry and could afford to clear mine fields while moving slowly and carefully through them, the soldiers absolutely did defuse mines to use them themselves (as ECBs planted as many minefields as they cleared, a consequence of advancing and retreating in turn over the same terrain), so it seems every enlisted member of the Engineer Combat Battalion was capable of rolling against Explosives (EOD). They just preferred to avoid doing so while under fire and liked to get bonuses for Extra Time. That suggests it's a skill you want to avoid failing a skill roll against, not that only the most agile soldiers can ever improve it above default.

Originally Posted by johndallman

The DX 12 requirement is legacy from 3e. It could be claimed that armies would be fussy about who they taught EOD, and would avoid teaching it to people who weren't notably good with their hands, but that should be explicit, and HMD would definitely be usable.

In WWII, Korea and pretty much any war not fought by a 1990s or later Western democracy, armies would teach anyone who'd not desert at the mere suggestion to look for mines by crawling around with a knife.

There wasn't the same political sensitivity to casualties, any casualties. At least with trained troops clearing minefields, they got through them while losing fewer men than the militaries who used human wave attacks for the same purpose,

For that matter, there are charitable NGOs clearing up mines in former warzones. True, they absolutely love former combat engineers, EOD personnel or experienced demolition engineers, but they'll take anyone who'll sign a waiver and agree to follow the decisions of the people in charge. They don't need to take gymnastics tests before they are able to start learning to clear minefields and disable mines.

[David Johnston2]

Originally Posted by Icelander

So, why make DX 12+ a prerequisite for the skill as a whole, instead of just that technique?
And High Manual Dexteriy should definitively be able to substitute for DX here.

I believe we can turn to the HMD's description and determine that since it raises DX for applications that involve using your hands and disarming a bomb uses your hands by the RAW, you should use your DX modified by Manual Dexterity to determine whether you have the prereq.

That being said, the ways of dealing with explosives that don't involve actually trying to handle and defuse them could all be covered by Expert: Explosives.

[Pursuivant]

I second the opinion that DX 12 is a legacy from GURPS 3E.

I agree that it isn't a requirement for all applications of EOD, but presumably when you need high DX to do EOD you REALLY need it. I'd rule that each missing level of DX + High Manual Dexterity gives a -2 penalty to tasks which require superior DX, such as carefully lifting mines with tilt plates or similar anti-handling devices or disarming fuses or explosives with anti-tamper features.

[Varyon]

The description of Explosives (EOD) indicates it is explicitly about getting in there with your hands and directly disarming the explosive. The uses you describe shouldn't require a high DX, and I agree that those uses that do require such should be able to use High Manual Dexterity to qualify. And I think Explosives (EOD) is the most logical place to put those uses.

Of course, I also don't think requiring DX 12 is appropriate - sufficient skill should be able to offset the problems of having merely average (or perhaps a bit below, so long as it's not from tremors or the like) DX. If you're fine with a bit more complexity, you can allow characters with DX below 12 to learn Explosives (EOD), but they suffer a penalty equal to (DX-12) - -1 for DX 11, -2 for DX 10, etc - to attempts to directly disarm explosives with their hands. Use DX adjusted by the bonus for High Manual Dexterity (or the penalty for Ham-Fisted) in place of full DX if applicable.

[cmdicely]

I wonder if this might be better treated as “for IQ-based applications that also involve manipulation of sensitive devices, use the lower of DX or IQ unless DX is 12+”, rather than an actual pre-requisite.

[Icelander]

I think a DX prerequisite is an unrealistic 3e relic. A DX 10, IQ 10 character with two levels of Talent that includes Explosives is already at least as steady with their hands when it comes to handling explosives as a DX 12 character.

4e treats Attributes as more complex and multi-faceted than such a simple prerequisite acknowledges. Talents work, for all intents and purposes, as sub-Attributes when it comes to the skills that fall within them. And 4e GURPS has a rule about floating skill rolls to other Attributes.

So, for the cinematic scenes of disarming bombs by circumventing anti-tampering devices with deft, sure-handed handling, let the skill float to DX if the GM feels that fits the scene, but the DX 10 guy with Explosives (EOD) at IQ+5 is still going to be plenty sure-handed for that specific purpose, whether that skill level was achieved fhrough a Talent or just spending a lot of points on Explosives (EOD).

[Pursuivant]

It is also possible that the DX 12+ prerequisite is more of a TL6-7 thing. At TL8+, most of the fiddly stuff that can get an EOD person killed can (or should) be done by robots. In that case, you're offloading the manual dexterity requirements to defuse bombs to the quality of the programs your robots are running.

[thrash]

Regardless of what the rules as written say, I have never met an EOD professional (officer or enlisted) who does not have uncanny levels of fine motor control. When they are still, they are dead still, completely unmoving; when they move, it is with purpose and precision. They never gesture with their hands when talking. It amounts to a tell, if you know what to look for.

This is more likely the result of selection and training than a prerequisite per se, but I can also imagine that someone without this level of control might not last long enough to learn the skill.