[Spaceships] Optional rule: dedicated power for weapons batteries

[Michael Thayne]

This is somewhat obvious, and I assume only wasn't made canonical because of its complexity. I've nevertheless decided to try to write a version of this rule that's as simple as possible:

A medium, secondary, or tertiary battery with one or more high-energy weapons (i.e. beams, electromagnetic guns, and/or grav guns) can be designated as having "dedicated power". A battery with this design option is not a high powered system. Instead, reduce the total number of weapons in the mount by half the number of high-energy weapons in the mount, rounded up. Each weapon "slot" used for dedicated power gives 80% of the discount for using a slot for cargo—in other words the power systems' cost per ton is 20% of that of a weapon. These adjustments to cost and number of mounts are cumulative with the effects of using slots for cargo.

At TL9, a battery with the dedicated power option can operate for 6 hours on internal fuel. An amount of rocket fuel equal to the system's "uninstalled" value provides an additional 24 weapon-hours of firing, in the unlikely event a ship spends that much time actively fighting without being able to refuel. At TL10+, double these values.

Example: an SM+9 freighter is unarmed except for three lasers in a small (SM+8) tertiary battery. Normally, this would cost $600K and leave 40.5 tons of space available for cargo in the "system". If the freighter uses the dedicated power option, two slots will be used for power instead. This adds $80K to the cost of the battery ($680K total) and reduces the cargo capacity to 37.5 tons.

Note: these rules are based on assuming MHD turbines, rounding against the spaceship designer when there's an odd-number of mounts that need to be powered. Of course, you could just refrain from rounding, but I'm trying to avoid making things too complicated.

Thoughts? Also, did I do my math right given my assumption of MHD turbines?

[AlexanderHowl]

A combination system should probably consist of three SM-1 components, as it is the simplest build. For example, a SM+9 spacecraft could have a Self-Defense Component, which would consist of a SM+8 weapon battery, a SM+8 hanger bay (for interceptors/shuttles), and a SM+8 fission reactor. The SM+8 hanger bay could possibly hold 30 SM+4 AKVs equipped with 20 16cm missile launchers each, allowing for 120 16cm missiles per turn for 5 turns when fully deployed, meaning that the average freighter would have some teeth.

[Rupert]

Your maths is off - a SM+8 hanger system holds 30 tons, and a SM+4 ship masses 10 tons.

Also, fitting 20 16cm launchers into a SM+4 ship is a neat trick, given that each one masses 0.5 tons, so they'll take up the entire ship's mass leaving no room for controls or sensors, let alone any manoeuvring capability - at best that's a 'missile pod', Honorverse style, which means the 'freighter' (really an auxiliary cruiser at this point) will need to provide all fire control and management for all those missiles.

So actually it's not 120 missiles per turn for five turns, but more like 30-45 missiles per turn. Still not trivial, of course. Mind you, it's also $2-3 million per salvo, and the total missile load will be worth a significant fraction of the 'freighters' value.

[Frost]

Originally Posted by AlexanderHowl

A combination system should probably consist of three SM-1 components, as it is the simplest build.

I would second this, I have used this build for weapons on modular spacecraft for a while.

Under the rules for smaller systems a small MHD and two major batteries, is a perfectly legitimate fit and looks for all the world like a self powered medium battery.

[Michael Thayne]

I don't know if combination systems of SM-1 components are actually "simpler". Part of the reason for this is just to condense what you write down on the spaceship's sheet. Also, the SM-1 components thing doesn't help with not overspending on the power plant for a secondary/tertiary battery that is either under-gunned or uses a mix of high-energy weapons and conventional guns/launchers.

[Rupert]

While the rules for smaller systems and the like certainly allow for 'self powered' units, I think one reason that this wasn't written as an option is that it removes one of the interesting effects of being hit - you can't lose power and have to frantically repair a power plant or over-power a surviving one to get power back to systems.

[Frost]

Originally Posted by Rupert

While the rules for smaller systems and the like certainly allow for 'self powered' units, I think one reason that this wasn't written as an option is that it removes one of the interesting effects of being hit - you can't lose power and have to frantically repair a power plant or over-power a surviving one to get power back to systems.

While it may be dramatic it doesn't always make that much sense so it's good to have the option. I think that it is not given specifically in part because it is a fairly obvious use of the smaller systems rules.

[Michael Thayne]

Originally Posted by Frost

While it may be dramatic it doesn't always make that much sense so it's good to have the option. I think that it is not given specifically in part because it is a fairly obvious use of the smaller systems rules.

It's an extremely obvious use case, in fact Spaceships 8 (the main canonical source for examples of those rules) has multiple examples.

[AlexanderHowl]

Originally Posted by Rupert

Your maths is off - a SM+8 hanger system holds 30 tons, and a SM+4 ship masses 10 tons.

Also, fitting 20 16cm launchers into a SM+4 ship is a neat trick, given that each one masses 0.5 tons, so they'll take up the entire ship's mass leaving no room for controls or sensors, let alone any manoeuvring capability - at best that's a 'missile pod', Honorverse style, which means the 'freighter' (really an auxiliary cruiser at this point) will need to provide all fire control and management for all those missiles.

So actually it's not 120 missiles per turn for five turns, but more like 30-45 missiles per turn. Still not trivial, of course. Mind you, it's also $2-3 million per salvo, and the total missile load will be worth a significant fraction of the 'freighters' value.

Sorry, meant 20 16cm missiles each. And you are right, it is 30 tons.

[Rupert]

Originally Posted by Michael Thayne

It's an extremely obvious use case, in fact Spaceships 8 (the main canonical source for examples of those rules) has multiple examples.

It is, and I do it myself from time to time. However, I don't lump it in with something else and treat it as a single system.

Also note that the Spaceships 8 ships that do this, of which I found five, all have that under-sized power plant as their only source of power for high-energy systems, and have only one high-energy system to supply, so they actually remain quite simple in play.

My concern is that if one starts having systems with built-in power-packs, things become quite complex when damage is taken. Can the self-contained systems share power? If so, how much are they actually producing? And if they can, really the only difference between them and the normal systems is that their power plants are immune to getting shot up, dodging a chunk of the damage system. If they can't, there's some slight cost to them, but they're still really just a dodge, I think (though if someone did this with anti-matter power plants, making every powered system volatile, I think I'd be inclined to let them).