[Spaceships][Vorkosigan] Off-Size Systems and Power

[SCAR]

GURPS Vorkosigan includes a custom version of Spaceships, and as part of that it has an inset on 'Off-Size Systems', i.e. installing smaller and larger systems in a Spaceship (SM +/-1) and half-systems.

It states: Smaller power plants can only power other small systems.

Installing a Big Gun is one of the listed reasons for installing a larger system in a spaceship.

Nothing however is mentioned about the Power requirement for a larger system, except, since a smaller power plant (e.g. SM+7) can't provide enough power for a normal system (e.g. SM+8), then we have to conclude that a normal power plant (e.g. SM+8) can't power a larger system (e.g. SM+9).
Therefore, as well as installing a larger gun, you would have to install a larger power plant to power the gun.

This raises the question of how many normal sized systems can a larger power plant supply? (more generally, what sort of scaling is there between Power Points and different SM's?)
If a smaller-power plant simply cannot provide enough power for a normal system (as stated), can you assume that a larger power plant can power all smaller systems for free? or for 1 PP.

This would make installing a one SM larger power plant in a spaceship much more economical than 3 or more normal SM power plants!

I know some of this has been discussed in various threads, but I'm fairly sure that Vorkosigan is the first official appearance of rules for Off-Size systems, and I'm hoping there might be some official ruling on this sort of issue, perhaps in a future Spaceships supplement?

[joelbf]

Disclaimer: I don't own Vorkosigan (yet).

If this follows Spaceships a +1 SM powerplant should produce 3 times the powerpoints, and a large system should use 3 times the powerpoints.

A -1 SM powerplant should produce 1/3 times the powerpoints and the the small systems should use 1/3 the power.

This becomes obvious when you look at for example the beam output of a battery (of the same size) for different ship sizes.

[David Johnston2]

Originally Posted by SCAR

Therefore, as well as installing a larger gun, you would have to install a larger power plant to power the gun.

Or multiple power plants.

Actually the thought which occurs to me is sparked by the capacitor topic. It could be that firing your Wave Motion Cannon might consume all of your power points, or even the power points from more than one turn.

[SCAR]

Originally Posted by David Johnston2

Or multiple power plants.

Actually the thought which occurs to me is sparked by the capacitor topic. It could be that firing your Wave Motion Cannon might consume all of your power points, or even the power points from more than one turn.

Like the main gun on the Excaliber from Babylon 5 - Crusade, the firing of which shuts the ship down for a minute (if I remember correctly!)

Originally Posted by Boobis

Disclaimer: I don't own Vorkosigan (yet).

If this follows Spaceships a +1 SM powerplant should produce 3 times the powerpoints, and a large system should use 3 times the powerpoints.

A -1 SM powerplant should produce 1/3 times the powerpoints and the the small systems should use 1/3 the power.

This becomes obvious when you look at for example the beam output of a battery (of the same size) for different ship sizes.

The 1/3 does seem to be the obvious answer, except it doesn't quite hold.

An Antimatter plant (which does exist in Vorkosigan) produces 4 PP, by the 1/3 rule, a small Antimatter plant would produce 1.333PP which would be enough to power a single, normal size, high-energy system, which contradicts the statement that a small power plant cannot provide enough power for a normal system!

If it isn't x3 per increase in SM, I'm not sure what it would be though!

[Langy]

An Antimatter plant (which does exist in Vorkosigan) produces 4 PP, by the 1/3 rule, a small Antimatter plant would produce 1.333PP which would be enough to power a single, normal size, high-energy system, which contradicts the statement that a small power plant cannot provide enough power for a normal system!

Yes, but there are no 3PP power plants. They likely didn't include the 1/3 rule because you'd wind up with fractional power points - which increases game complexity slightly.

[Diomedes]

Originally Posted by Langy

Yes, but there are no 3PP power plants. They likely didn't include the 1/3 rule because you'd wind up with fractional power points - which increases game complexity slightly.

The solution is to make the small power plants put out normal power, and just triple the output of the full-size ones. And obviously, triple the consumption of the full-size systems, too.

[Ulzgoroth]

Originally Posted by Diomedes

The solution is to make the small power plants put out normal power, and just triple the output of the full-size ones. And obviously, triple the consumption of the full-size systems, too.

Or just don't be afraid of fractions...

Technically there are 3PP powerplants in the form of de-rated antimatter (and de-rated super fusion and total conversion, if available). But yeah, this looks much like opting for simplicity over accuracy, unless there's a strange setting rule involved.

[jacobmuller]

originally posted by Ulzgoroth: This would make installing a one SM larger power plant in a spaceship much more economical than 3 or more normal SM power plants!

Maybe I'm wrong but, depending on SM, you'd either pay the same or an extra 11'%.
The benefits come from fitting in extra, just good enough, optional systems - versatility at the cost of effectiveness. Just like a PC with 3 ok melee skills v's one good skill.

Larger Defenses "Use twice the dDR or reflected damage dice of the original system." This sounds good but it's like the Power Plants - depending on SM, you get nothing extra or lose perhaps 12% compared to three normal SM units.

NB: the Courier on p206 uses Off-Size defense systems but the stats seem wrong. If I'm reading the rules right, it should be 100dice and dDR 2/233. SM4 defense values are not 1/3rd SM5. For that matter, keeping consistancy with the Larger Sytems, it should be "use 1/2 dDR" etc, not 1/3.

[Fred Brackin]

Originally Posted by David Johnston2

Actually the thought which occurs to me is sparked by the capacitor topic. It could be that firing your Wave Motion Cannon might consume all of your power points, or even the power points from more than one turn.

If Spaceships did have capacitors firing the Extraordinarily Large Gun could drain those but could not keep your power plants from producing energy for the next minute (which is why this sort of idea has always been sub-rational except maybe if your "ships" really were living beings).

Mostly though Spaceships ignores questions of stored energy and uses only measures of sustained output and consumption. That's why a main battery uses the same amount of PP no matter how long the Turn length is.

[vicky_molokh]

Originally Posted by Fred Brackin

Mostly though Spaceships ignores questions of stored energy and uses only measures of sustained output and consumption. That's why a main battery uses the same amount of PP no matter how long the Turn length is.

That's because it takes it one second to fill all capacitors for a RoF 1 battery anyway.