Tuesday, March 10, 2015

Cloak and Dagger Spaceships

Gurps: spaceships is an wonderful product, and one I love. But using it with no tweaking tends to a very specific style of combat. So how do you tweak it to run a specific style?

The Genre

Of the many styles of spaceship combat, it can be argued that this is the most realistic. In this style, weapons are powerful and most military ships can destroy each other with a single shot -- if they can find the enemy. This is actually fairly close to how the base rules work. These rules can be used for both hard science games and super-science games, but the focus here is on hard science -- in sharp contrast to many of the other styles.

Detecting the enemy

Use the basic rules on Spaceships 1 p. 44-45. A few shortcuts are relevant:

When building or introducing any ship, note its basic visibility score: +34 (plain sight in deep space), -2*(TL-6) (stealth hull), + SM (overall size), + ? (emissions signature).
 Calculate its sensor bonus. Please note that systems can be scaled up or down by a factor of three to provide a +1 or -1 bonus. (though a 9-system array for +2 is likely to be a defensive emplacement rather than a ship)

Its worth noting that SM doesn't give an advantage to a ship to be seen first-- SM gives a bonus to be seen, but also gives an equal bonus to see another ship. Once spotted though, the larger ship will be much more easily able to keep track of the smaller ship.

Attacking (and Defending)

For true cloak and dagger submarine style combat, the attack should just be a formality. Or your only chance should be tactics that are as likely to fool ten missiles as two -- anything else will hit. A GM should waive the attack as a formality. This does not mean defenses are inappropriate.

Dodging:
Let the pilot be awesome! Despite the fact that multiple shots are being taken, There should probably only be one dodge roll per round, regardless of the time frame or number of shots. A GM who wishes to make this more difficult should apply a difficulty modifier, not require multiple rolls. The reason for this is just statistics -- and it gives the GM a better understanding of the odds he's working with. If you want the kill to be automatic, just say so.

Decoys:
Let each ship carry a number of decoys it can let off. I suggest a baseline of one decoy per system, but more are certainly possible (but see EMC below). Deploying a decoy is a defense roll a skill roll based on Electronics Operation (ECM) to fool the enemy. This tactic should be valid for both beam weapons and missiles. In addition, it can give the impression of a direct hit. In more extreme cases, a ship can be built with the ability to actually jettison systems -- though the systems actually likely to work (power generator, drives) will cripple the ship -- but leave the crew alive and perhaps still in possession of weapons of their own. A decoy should provide a bonus or penalty depending on how visible and energetic it is, and TL difference should be applied as well.

ECM:
Some settings have extensive ECM. The point of ECM is to convince the attacker that the target is somewhere else. If ECM can be used many times, allow a defense roll based on electronics operation (ECM). At GM option, multiple systems could provide bonuses (I suggest +1 per doubling or trippling) or very expensive systems could provide bonuses.

If a defense succeeds, the GM should require the attacking ship to re-roll to detect their quarry.

Defenses can only be taken if the defender is expecting an attack. If beam weapons are in use the first hit is usually free. Missiles can be seen coming and always give the defender a chance to defend -- but generally have far superior damage, and at some ranges, are the only option.

Multiple attacks should require multiple defenses only if the attacks are of very different natures. For example, if they are being attacked by both conventional missiles and bombs warping into the general area. Defending attacks from multiple angles should merely give a  -1 (two angles)  or -2 (three+)  to defenses. Similarly The GM is free to add any setting appropriate difficulty modifier to all defense rolls.

Damage

The destruction of the ship is assumed to either be caused by a single missile or a series of beam weapon hits in rapid succession. Even the smallest spacecraft should be able to destroy another with the right missiles. If not, you're either not playing with cloak and dagger spaceships, or the largest ship should be treated as a series of emplacements rather than a single ship. Yes, this damage system is a little more abstract than gurps combat typically is -- but it feels right.

A GM who wants to give the characters a chance to escape can let them roll against spacer to get their helmets up, make it to escape pods, and eject before the ship is destroyed.

A GM could leave the ship a mere wreck (rather than a cloud of vapor), if he wishes to be cinematic. In such a case, have each system roll against ship HT. volatile systems have -5 to this roll, and some very rugged systems (Armor, Cargo hold) may have a bonus. Systems that fail are destroyed, while the others are merely damaged.

It's possible to be only nicked. This is most likely the result of failing to defend against a proximity detonation or a series of beam weapon shots by just a little, or the result of not defending against beam weapons until the first hit. This should be handled with the HT roll for making a wreck, but instead of 'destroyed' read 'damaged'. If only the first beam hit, choose only one system to effect.

Armour: As damage is not actually being calculated, Armour has precious little to do. Armour should effect the HT of the ship: 1 System HT 8, 2 systems HT 9, 3 systems HT 10, 5 systems HT 11, 7 systems HT 12, 10 systems HT 13, 15 systems HT 14. The difference in armour TL and weapon TL should be applied as a modifier to all HT rolls.

Ship Building

So what do efficient battle ships for this style look like?

Actual weapons systems are minimal, probably just one system. An enhanced sensor array is an absolute must. You're likely to minimize the signature of your engines to the point where you're slower than a commercial ship (but so much stealthier). If you think you can get away with it, you'll run on fuel cells or some non-nuclear power.

Smugglers will stick to small ships --- you can't see them, but they can't see you!

Happy Hunting to you all!

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