Rules to model reasonable capital ship combat

[Bulwer]

As they were coming out, I really enjoyed Fear the Boot's series of essays on capital ship combat. Being a gaming nerd in addition to a sci-fi nerd, I was thinking about how one might model combat of that type in a tabletop gaming environment.

On the one hand, entering into this exercise means committing to making "realistic" (as opposed to cinematic, I suppose) space combat rules. On the other, no one wants FATAListic levels of detail.

Would a straight adaptation of person-to-person combat rules be adequate here? For, say, d20, that would be something like "this ship is this accurate with this weapon, so at a range of [large number] meters, they're at +5 to hit AC 22 of the enemy starship."

Yes, it probably would, but what if you wanted a more self-indulgently nerdy set of rules? Any thought?

[Djinn_in_Tonic]

Hmmm...a friend of mine and I once created a very rudimentry set of rules for such a situation, which ranked each part of the ship on a scale of 1 to 10 (weapon strength, shields, autopilot, hull strength, and such things), and determined damage taken on a percentage calculation (as we determined that sufficiently high-tech weaponry and targetting equipment would not miss enough for us to have complete misses). The pilot's Skill modifier also figured into the equation, giving a skilled pilot a greater chance to escape. I can try to find it if you're interested, but it's rudimentry at best, since the game in question was mostly land-based.

[Bulwer]

Oh, I don't have a purpose for this or anything, it was just a thought. No need to dig things up.

A condition that could lead to clean misses are missile weapons versus countermeasures of some kind. Of course, that might just mean that anything traveling at less than relativistic speeds (energy weapons, that is) is impractical.

[Kornaki]

Someone posted a game like this already

http://www.giantitp.com/forums/showthread.php?t=112190

Might be worth checking out

[Stormthorn]

If its not going to be cinematic then you will need a rule for acceleration and turning. I would suggest that for every 5-10 (depending upon ship meneuverability) base units-of-measurment the ship moves it may turn 45 degrees. A ship not moving at all can rotate up to 90 degrees in its turn. Emergency turns can be made for up to twice that but the ship takes X damage from the shear stress along its hull.

[Bulwer]

If its not going to be cinematic then you will need a rule for acceleration and turning. I would suggest that for every 5-10 (depending upon ship meneuverability) base units-of-measurment the ship moves it may turn 45 degrees. A ship not moving at all can rotate up to 90 degrees in its turn. Emergency turns can be made for up to twice that but the ship takes X damage from the shear stress along its hull.

I dunno, if I were modelling momentum and turning in space, I'd go whole hog. A maximum of x m/s^2 (or meters per round squared, or whatever) of acceleration per engine, with directionality mattering if you've got engines that work only in one direction. Turning would just be rotating the ship around its center of gravity, so as to bring engines or weapons to bear in the right direction. Of course, to stop your rotation afterwards, you'd need an opposite impulse than the one that started you turning.

And Kornaki, I saw that, but that's very abstract and cinematic, whereas this is thinking on that issue in a different direction.

[lesser_minion]

Amazingly, one of the homebrew projects I'm sort of working on on-and-off at the moment is a TMG based on this. It sacrifices realism in a few areas (I ignored 3d combat for simplicity, for example), is nowhere near finished, and may not be the droid you're looking for, but you might want to take a look.

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If you wanted rules for within D&D, you probably could use the standard rules. You would have to clarify the flying rules a bit, and establish exactly how your ships work (in terms of armour, shields and weapon systems).

You may also have to make a few changes - for example - making ships move the same distance as they moved the previous round, +/- a few thousand kilometres.

Weaponry is also an issue. Depending on the weapon type, there may or may not be a cutoff range - eventually, the target ship is going to have so many possible locations (by the time the round gets anywhere near) that there is no point shooting at it. A missile or similar could be more useful though.

[Bulwer]

That'd be a use for smaller ships: spotters. They obviously couldn't get information to their base ship any faster than any other means of getting that information, but they could assist in guiding smart missiles on their way.

[lesser_minion]

The actual idea behind it was that they could pass information on fall-of-shot and the like back to their parent ships, although smart missile guidance works as well.

In the end I all-but dropped it in favour of assuming that most weapons were the sort which could be justified in having a cutoff range.

[Stormthorn]

A guy i know told me of a game where you made your ships from a points pool. He won by having uncapurable planets. He made ships with no movement capabilities and just left them to defend the planet that spawned them. With those extra points he could give them better armor and firepower than anyhting capable of motion.

[Ashtagon]

If nothing smaller than a capital ship can interact with them in combat, a simple approach would be to stat them out as fighter-class characters with ranged weapons. Boarding actions would be PC vs NPC in a standard dungeon-esque combat situation.

[Rockphed]

I would think that the best way to do it would be to stat out each weapon emplacement, engine or vulnerable command center on each capital ship and then calculate ranges based on both the location of the firing gun and on the location of the target. Depending on the scale you are using, this could change the annoyance quotient of the whole excercise by quite a bit.

[DMfromTheAbyss]

I rather liked the old West End Star Wars system for it's capital ship combat. Although it tends towards the slow, you really get the "Two gigantic war machines pounding on each other till something breaks" kind of feel. Saddly the more modern variety (d20) of star wars looses this.

Ultimately you need to have a setting, and start rolling into specifics before you can even start coming up with a system though. If you're looking at huge distances between opposing ships traveling at speeds approaching C in a graceful dance of death, or point blank engagements with armored juggernoughts parked next to each other is entirely dependant on technology. And frankly you'd want a different metric to describe each of these.
Weaponry, (types, ranges, direction of fire etc)
Accuracy (or do we have autohit computers or is hitting a long shot)
Armor/shields,
dodging/evasion/manuverability
pilot/weapon crew skill
Acceleration/speed.
Each of these dependant on the "feel" you are going for (and the technology involved) could be critically important, or utterly ignorable depending. If your dealing with high speed ships, likely you'd have piloting and speed/acceleration/manuverability and targeting as key components of the fight. With the slow juggernought situation these are fairly irrelevant compared to firepower, and armor. The complexities and interaction between which of these factor in strongly will determine the feel of your system.

[Hawriel]

As they were coming out, I really enjoyed Fear the Boot's series of essays on capital ship combat. Being a gaming nerd in addition to a sci-fi nerd, I was thinking about how one might model combat of that type in a tabletop gaming environment.

On the one hand, entering into this exercise means committing to making "realistic" (as opposed to cinematic, I suppose) space combat rules. On the other, no one wants FATAListic levels of detail.

Would a straight adaptation of person-to-person combat rules be adequate here? For, say, d20, that would be something like "this ship is this accurate with this weapon, so at a range of [large number] meters, they're at +5 to hit AC 22 of the enemy starship."

Yes, it probably would, but what if you wanted a more self-indulgently nerdy set of rules? Any thought?

A sci fi ship combat system.

How about Star Fleet battles

http://www.starfleetgames.com/starfleetbattles.shtml

Or its newer version of federation commander

http://www.starfleetgames.com/federation/