How to design power-draining heavy weapons?

[Pursuivant]

One science fiction trope is mysterious weapons which can somehow shut down power sources in the same way that EMP can fry electronics. Think Gray alien spaceships that leave car batteries dead or shut down TL6 internal combustion engines which don't use electronics.

Even more advanced technology can drain vast amounts of power, temporarily rendering even powerful zero-point energy stardrives inert, leaving their victims helpless and drifting in space.

While it's relatively easy to design a character who can absorb, destroy, or leech power, I haven't found any good rules for weapons that do the same job, especially heavy weapons.

The closest equivalents are the Microwave Disruptors (GURPS Ultra-Tech, p. 121), but they're designed as short-ranged tactical anti-robot or materiel destruction weapons and can't affect generic power supplies or powerplants.

Are there any weapon designs I've missed from Ultratech, Spaceships or other books?

Any suggestions on where to start?

[Varyon]

Mechanically, you'd typically just design these as Afflictions - the target machine/power source rolls against its HT (typically 12 for artifacts in good condition; cheap and/or poorly-maintained artifacts will be lower, ruggedized and/or impeccably-maintained artifacts will be higher), at some penalty set by the weapon (and a bonus equal to DR, although note many such weapons will have an Armor Divisor). For most depictions, this will be a large penalty (and sizable Armor Divisor) and the artifact will shut down on any Failure, but won't be damaged - indeed, it will usually be able to come right back up as soon as the weapon is no longer in use, indicating such devices would probably call for a roll against modified HT every second until the artifact(s) shut down, then stay shut down until the weapon is turned off or goes out of range.

Personally, I'd be more inclined to build them as No Damage attacks that have the shutdown effect as a Side Effect, as I feel this handles things like armor, large targets, etc more appropriately, but RAW devices like this use Affliction mechanics.

[Pursuivant]

Originally Posted by Varyon

Mechanically, you'd typically just design these as Afflictions

That's another good approach for building characters, but I was wondering if there were any existing rules for gadgets, particularly heavy weapons for use in spaceship combat.

I took a quick look at the Spaceships series and didn't find anything. If I have to DIY, I'm inclined to design power-draining systems as massive weapons with relatively short range.

I'd base their chances of knocking out another ship's power, or how much power they can drain, based on maximum Size the weapon can affect vs. target size, with big bonuses for superior TL. (The the usual trope is: huge super-advanced alien ship surprises the protagonists, hits them with the energy drain ray, and leaves them in the dark and running out of air.)

There would have to be three types:

Energy Drainers, which briefly drain some or all of the target's available energy.

(This is the classic gray alien "car-staller" trick where the car's electronics go crazy and the engine cuts out while the ship is overhead but it starts up normally once the ship leaves. On a larger scale, it's the weapon that the city-sized alien motherships use to knock out all the power in the city it's hovering over.)

System Disruptors, which randomly knock some or all ships' systems offline. These would be the lowest TL versions, since they're effectively Ultratech Microwave Disruptors.

Drainer-Disruptors, which drain energy and knock affected systems offline if all energy is drained.

Selective weapons which allow you to target specific ships' systems are a higher TL improvement.

At a very high TL, you might have Energy Absorbers which steal energy from the target and store it in "capacitors" aboard the attacker's ship. On the next combat turn, the attacker can use the stolen energy to power their own ships systems.

Tactical weapons would be similar to Microwave Disruptors, but they'd be big and relatively short-ranged area effect beam weapons designed to drain or disable small Ultratech gadgets & weapons. They mostly be anti-materiel weapons, but could be devastatingly effective vs. battlesuit troops.

[Anthony]

I feel like there was a device in 3rd edition that drained power cells, but I can't find it. There's definitely the drain power spell.

[Pursuivant]

Originally Posted by Anthony

I feel like there was a device in 3rd edition that drained power cells, but I can't find it. There's definitely the drain power spell.

Might have been for Black Ops or in the Warehouse 23 book. I'll go hunting.

[johndallman]

Originally Posted by Anthony

I feel like there was a device in 3rd edition that drained power cells, but I can't find it. There's definitely the drain power spell.

Energy Web, Ultra-Tech for 3e, p. 59-60.

[Pursuivant]

Originally Posted by johndallman

Energy Web, Ultra-Tech for 3e, p. 59-60.

Thanks much!

This fits the niche for heavy tactical power drain weapons and I can scale up from there.

I can see why it didn't make the cut for GURPS 4E Ultratech, however: TL14^, 60 lbs., 500 yd. range, affects a 16-yard diameter sphere, power for just 50 seconds of operation (i.e., just enough to completely drain all power cells which remain in the area of effect for the entire duration), drains 20% of original power cell energy per 10 seconds of contact time. Meanwhile, your opponents are shredding you with TL14 firepower which has vastly superior range.

It would make more sense as an always-on security device continuously powered by building power.

[Anaraxes]

Originally Posted by Pursuivant

It would make more sense as an always-on security device continuously powered by building power.

Or a tactical warhead, to be used on your high-tech, power-cell-toting adversary. Drop them among the enemy troops as the opening round of your attack. Sure, they've got spares, or can recharge them, or storage shielded against the power-draining tech. But that takes time and disorganizes the defense, or stalls the attack when used defensively.

[Pursuivant]

Originally Posted by Anaraxes

Or a tactical warhead, to be used on your high-tech, power-cell-toting adversary. Drop them among the enemy troops as the opening round of your attack. Sure, they've got spares, or can recharge them, or storage shielded against the power-draining tech. But that takes time and disorganizes the defense, or stalls the attack when used defensively.

Area of effect is a bit small for a warhead given the weight but an improved smaller version with the same or similar area of effect could certainly work as would a "landmine" version.

I was thinking of an always on security device because it would be easy to channel and trap intruders within a building, maximizing "contact time" and making it harder to move out of the area of effect. It might even be a standard ultratech screening device prior to going into places like prisons of SCIFs.