Action Vehicular Combat

These rules are based on the GURPS Action Chase rules starting on Page 31 of GURPS Action 2: Exploits. However, they have been substantially updated for Psi-Wars (though they can be used for other systems as well).

Range Band Table

Psi-Wars uses an expanded Range Band table, both for ranged combat and for chase scenes. Use the low range penalty for all ranged attacks.

Range Band Starting Range Range Penalty Notes
Close 0-5 -0 to -2 Melee Range; Apply bulk penalty to ranged attacks at this range
Short 6-20 -3 to -6 Pistol range
Medium 21-100 -7 to -10
Long 101-500 -11 to -14 Rifle Range
Extreme 500-2000 -15 to -18 Sniper Range
Distant 2001-10,000 (5 mi) -19 to -22 Missile range
Beyond Visual* 10,000-50,000 (5-25 mi) -23 or more Requires active sensors to engage
Remote* 50,000+ (25+) -27 or more* Only very large vehicles can engage one another at this range
Beyond Remote* 200,000+ -31 or more This is beyond any tactical consideration. Chases on this scale take hours, rather than minutes.

*These range bands have some special rules. At Beyond Visual, characters cannot spot one another unaided; they may only engage in combat if supported by sensors such as long-range ultrascanners. Remote represents an optional range at which vehicles that might still influence combat or a chase if they have sufficient long range weaponry or electronics; For a ship to be tactically relevant, it must have comm, sensor and weapon ranges of at least 100 miles; reaching Remote requires two range-band shifts; remote vehicles cannot gain advantage on other vehicles; give all attacks at this range the full -30 penalty! Remote range is only possible for space-bound vehicles; it represents orbital artillery or very distant space warships that might still be tactically relevant.

Beyond Extreme is irrelevant outside of vehicular combat;

Beyond Remote is beyond the scope of the Action rules: anyone who is Beyond Remote makes no impact on the chase or combat on a tactical level.

Rounds

Lucky Breaks, Expanded

As described on page 32, certain maneuvers require a “lucky break” to function. These represent moments of serendipity where new options open up to the pursuer or pursued because of changing, dynamic circumstances. These can be purchased with character points, or represent uses of Serendipity or can be acquired via Foresight provided the proposed “Lucky Break” represents something the character could have reasonably planned for; finally, all Ace Pilots get one Lucky Break per chase scenario (just like a free use of chase-limited Serendipity).

Lucky Breaks can also be used for the following:

  • To invoke a new obstacle, dead end, rough terrain, bystander or opportunity. The character may still need to Force his opponent into such terrain. This might represent a planned roadblock or the sudden arrival of allies. See Thrill of the Chase, below.
  • To increase the severity of a successful wound against a target by 2 levels.
  • To ignore all attacks for one round; circumstances conspire to prevent you from being hit at all.

Use the rules found on page 31 of Action 2.

Round Sequence

You may use the sequence noted on Page 32 of GURPS Action 2 (especially if the chase is literally a chase). Alternatively, the character with the higher Basic Speed or the character with Advantage is declares second and resolves first (like the “Pursuer”) while the other character declares first and resolves second (like the “Quarry”). This works best for dynamic “dogfight” style combat, or running gunfights.

Characters driving vehicles that have configurable options (afterburners, variable geometry wings, angular force screens etc), the configuration of the vehicle must be set when the player declares his character’s maneuver.

Chase Maneuvers

In addition to the notes on page 32 of GURPS Action 2, the following rules apply:

Advantage: A character who wins a “chase roll” gains advantage over his opponent. This represents superior positioning! Advantaged characters gain a few benefits over their opponents, noted in the Chase Roll resolution roll. Once advantage has been gained on a target, it cannot be lost until the character loses a chase contest or he switches targets for his chase maneuvers.

Collision Range: Any vehicle whose speed bonus is greater than the absolute value of their range penalty is at collision range. This is “close” for humans, but may be much greater for faster vehicles. “Collision Range” is important for certain Conditions.

Facing: Vehicles have 6 faces: Front (F), Right (R), Left (L), Back (B), Up (U) and Down (D). A vehicle that “pursues” its target has its Front (F) facing its opponent, while a vehicle that “evades” its target has its Back (B) facing its opponent. When a chase or fight begins, or when two vehicles which had not previous engaged one another do so, they are “Neutral” to one another, and the GM can determine what their initial facing towards one another is. Any fixed mounts on the vehicle must have the proper facing to fire. Characters who are Advantaged may make an attack at any facing of its target (Within reason: generally two ground vehicles cannot attack the “Top” or “Bottom” of the other, for example). Note that in a chase or a dogfight, facing is, in fact, highly dynamic. This represents the facing that most commonly faces your opponent.

Match Speed: Characters who are already Advantaged against their target and gain Advantage again may “match speed.” The benefits of “matched speed” are noted in the attack rules!

Pursuit or Evasion: Instead of worrying about “Pursuer” or “Quarry,” when a character chooses a maneuver, he must declare if he pursues or evades. A pursuer may not increase range between himself and his target, while an evader may not reduce range between himself and his target. Two characters may attempt to Pursue or Evade one another! A vehicle with a stall speed may not pursue a target that is Advantaged against it.

Static: Static maneuvers cannot be undertaken by vehicles with Stall Speeds unless that Vehicle has first Stopped. Static vehicles automatically lose Advantage and cannot gain it.

Specific Maneuver Updates:

What Counts as a Fighter?

The GM ultimately arbitrates what is a fighter, corvette or capital ship. As a general rule of thumb, fighters are vehicles between SM +4 to +7, or with sufficient speed and agility to have a +16 or better on their chase rolls; a Corvette is between SM +7 and +10, or has between +11 or +15 on their chase rolls. A capital ship is generally SM +10 or larger, or has a +10 chase roll or worse. Characters with the “Soar like a Leaf” perk may treat their corvette as a fighter for all

Attack: Vehicles with a stall speed may not Attack. Facing: F

Disembark/Embark: Facing: Any(Operator choice). May also represent boarding a vehicle or entering/departing a carrier in a fighter, or escaping a vehicle via ejection system or lifepods. Minimum necessary range is Collision range. The maximum number of carrier launches per turn is determined by the hangar capacity! Attempts to board another ship requires a Control Roll from the vessel, like a Ram, but instead of doing damage, a properly equipped ship latches on and boards. Characters who want to leap from one ship to another and sneak aboard airlocks might require a Jumping or Free-Fall roll, and then Force Entry or Electronics Operations (Security) roll to get aboard.

Emergency Action: Facing: Any (Opponent’s choice).

Evade: Facing: B; Chase Roll: -2; The vehicle gains a +2 to dodge. If it gains any range shifts as a result of the chase roll, it must use them to increase range.

Force: Requires Collision range, rather than Close range. Facing: Any (Operator’s choice).

Hide: Facing: Any (Operator’s Choice)

Mobility Escape: Facing: B.

Mobility Pursuit: Facing: F.

Move: You must note if you are pursuing your opponent (in which case you have F facing) or escaping your opponent (in which case you have a B facing). Note that two vehicles can attempt to pursue one another if both seek Advantage. Vehicles with a stall speed may not Pursue a vehicle which has Advantage against them (but they may Escape).

Move and Attack: Facing: F; if you have sufficient mobility to gain a mobility move, at the GM’s discretion, you may freely attack normally disallowed facings (such as the Top (T) of a ground vehicle with an aerial vehicle, or the Underside (U) of a boat with a submarine). Do not apply the -2 to the chase roll unless the driver of the vehicle is attacking with a side-arm, rather than using the vehicle itself to attack.

Precision Aiming: Facing: F; this represents taking an entire minute to precisely aim all weapons against a single specific target, typically used by “artillery cruisers,” battleships or super-weapon-sporting ships to “snipe” at targets from Remote ranges. This grants a +4 to all attacks on the next round provided the attacker uses the Attack maneuver (not the Move and Attack maneuver!), but it also grants any target aware of the attacker a +2 to dodge. This bonus only applies to attacks made against the target aimed against! Passengers may not attack during a Precision Aiming maneuver.

Reverse: Ignore this; this is better handled by the facing system and the fact that vehicles can switch between pursuer and pursued at will (and, in some cases, both are pursuers)

Ram: Requires collision range, not close range. Facing: F.

Stop: Facing: Any (Operator’s Choice). This can also be treated as a static maneuver wherein nothing happens, as opposed to surrendering a chase (especially in a space battle!).

Stunt: Facing: Any (Operator’s Choice). Vehicles with a stall speed may not Stunt against vehicles which have Advantage against them (but they may Stunt Escape). Stunts may also be High G. A High G stunt adds +1 to the chase roll, in addition to the bonuses gained from the Stunt itself, but requires an HT roll with the same prerequisites, bonuses and consequences as outlined in High-G dodge in Defenses (see below).

Stunt Escape: Any (Operator’s Choice); Stunt Escapes may be High-G, just as with Stunts above.

Passenger Actions

Capital ships have large crews that cooperate together to perform Passenger Actions. A capital ship may freely use its crew to perform any and all Passenger Actions below, assuming it still has at least its minimum crew complement. Such a crew performs its skill rolls with its Crew Skill. This defaults to 12, but may be anywhere from 10 to 15.
For more rules, see GURPS Action 2 page 33.

Attack: See GURPS Action 2 page 33. Characters onboard sealed vehicles (most space vehicles) generally cannot make attacks with their own weapons against other vehicles, but they may man turrets and attack with them, using all the normal rules for passenger attacks (ignore the standard -1 penalty for a passenger making an attack).

Board: Boarding a ship is automatic if the character is aboard a vehicle that has embarked via a launch pad. If the vehicle has attached itself to the hull of the target ship or the character has somehow made it through space on his own to land on the vehicle, assume that a handy airlock is somewhere nearby and the character may enter via an Electronics Operations (Security), Forced Entry or Lockpicking roll with a difficulty equal to BAD.

Chart Hyperspace Route: Before making a hyperspace shunt, someone must successfully calcuate a hyperspace route. Calculating a hyperspace route requires 5 minutes (or 5 turns in Action Vehicular Combat), a successful Navigation (Hyperspace) roll and either a computer capable of hyperspatial navigation or a robot with the proper programming. In addition to other navigational penalties, the navigator may accept time spent penalties at -2 per turn reduced (calculating a hyperspace route in one turn/minute imposes a -8 penalty). This action explicitly benefits from the bonuses of a “Star Chart” ops center.

Command and Coordinate: A high rank character may attempt to coordinate the efforts of characters making another Passenger Action. He may roll Leadership as a complementary roll or use the lower of his Leadership or the required skill to replace the crew skill of the crew undertaking the task (for example, the crew is trying to perform emergency repairs; normally this requires the Mechanic skill, and they have a standard crew skill of 12, but a PC has Mechanic-18 and Leadership-15, and so may coordinate the repair crews so that they repair with skill 15 rather than 12).

Emergency Repairs: If a vehicle has a disabled system, the crew can attempt to jury-rig repairs in a single turn. This requires a single person on a starfighter, shuttle or corvette, but requires a substantial crew on a capital ship (assume such crew is available unless circumstances dictate otherwise). Attempting to jury-rig repairs requires a roll against an appropriate specialty of the Mechanic skill at a -10 penalty. Characters with Quick Gadgeteer may halve this penalty! A jury-rigged component is not a permanent fix, and must roll HT the first time it is used in a battle (one such roll is sufficient for the entire battle). Complete repairs, or the repair of destroyed systems, are beyond the capabilities of characters currently locked in a cinematic fight. These rolls explicitly benefit from a “Work Center” ops center.

Operate Electronics: If a character is at a proper control system, he may support the vehicle by operating its electronics. This allows the character to engage in contests with opposing electronics operators: the character may attempt to communicate through a distortion scrambler (Electronics Operations (Comms)) or to detect a target that is actively jamming sensors (Electronics Operations (Sensors)) or to actively a jam both sensors and comms of another vehicle (Electronics Operations (ECM)). For more detail, see electronics and jamming below. These rolls explicitly benefit from a “C3I” Ops Center.

Seize Control: To seize control, the character must be at the controls of the vehicle (see Internal Movement below). See GURPS Action 2 page 33.

Tactical Coordination: The character may create a tactical plan for a formation of two or more vehicles (see Multi-Party Chases below). This requires the passenger be in full communication with said formation of vehicles and a successful Tactics roll. The passenger must choose a target of the tactical coordination (if that target is a formation of vehicles, they may resist with a Quick Contest of Tactics). Success allows the formation to gain one of the following benefits: +2 to chase rolls (Pursuit Tactics); either the target is at -2 to hit the formation or the formation is at +1 dodge (Defensive Tactics); either the formation is at +2 to hit the target or the target is at -1 to dodge (Offensive Tactics). These rolls explicitly benefit from a “War Room” ops center.

Wait and Attack (Point Defense): See Point Defense rules below.

Emergency Power Allocation


Some vehicles have Emergency Power Reserves, which can act as Energy Reserves for the purposes of "Vehicular Extra Effort." These represent more robust power-transfer systems, distributed energy capacitors and spare energy banks. Vehicles without Emergency Power Reserves can still "redline" and reduce their HT by one to gain the benefits of "Vehicular Extra Effort" (see "Machines and Fatigue," page B16); this represents overcharging certain systems, blowing out energy transfer systems, etc. Allocating Emergency Power Reserves requires a Passenger Action, a roll against an appropriate skil and a single point of the vehicle's Emergency Power Reserve (or one level of HT).

Emergency Power Reserves replenish at a rate of 1 per hour while the vehicle operates normally (provided the system has power at all), or all of its power reserves replenish after at least an hour of maintenance in a fully outfitted shop.

  • All Power to the Engines: Skills: Electrician or Mechanic (Appropriate vehicular specialization). For a single Action Vehicular Combat turn, double the Move of the vehicle; as a simplified calculation, apply a +2 to its chase rolls. This doubles fuel consumption for the turn (if that matters), and apply a cumulative -4 to the skill roll for this form of vehicular extra effort for each additional attempt to double your Move. Critical failure on this roll disables your engines.
  • Emergency Evasive Manuevers: Skills: Electrician or Mechanic (Appropriate vehicular specialization). Success grants a the vehicle a +2 to a single vehicular dodge; this always counts as a High-G dodge.
  • Emergency Firepower: Skills: Electrician or Armoury (Vehicular Weapons). Success grants a single weapon +1 damage per die or +2 damage per die by the weapons Malf is reduced to 14. A critical failure on your skill roll for this form of vehicular extra effort disables your weapons.
  • Emergency Screen Recharge: Skills: Electrician or Armoury (Force Screen). Rather than wait until your next turn to restore your force screen to full DR, do so immediately. This usually works best when a force screen is under a particularly intense barrage of lighter attacks.
  • Emergency System Purge: Skills: Electrician or Mechanic (Appropriate vehicular specialization). This allows a vehicle to ignore the effects of a failed HT roll due to a Surge attack, a roll to see if the vehicle remains operational, or a roll to see if a system was disabled, for the duration of one turn. The GM may choose to limit the effects of this an emergency systems purge to temporarily restore the functions of the energy system or systems that draw power, such as weapons, force screens and some engines. This has no effect on Destroyed systems, nor can it prevent a ship's destruction.
  • Emergency Weapon Recharge: Skills: Electrician or Armoury (Vehicular Weapons). Success restores half of all shots to a single weapon.

Internal Movement


To perform an action, one must be located in the proper location to perform that action (at the controls of a turret to fire it, etc). If the character is not at his location, he needs to spend a number of turns “moving” to reach that location. The number of turns depends on the size of the ship:
  • Starfighters and shuttles: 0 turns (Free movement, assuming movement is possible within the craft)
  • Corvettes: 1 turn
  • Capital ships: 2 turns

For especially large ships, the GM may require three or more turns of movement, but too many turns may slow the game down too much! For additional detail, see GURPS Spaceship page 63 (using 1-minute turns).

These rules assume unimpeded movement, but the GM may create obstacles for characters to bypass. Such obstacles can be handled by a roll against a single skill with a difficulty equal to BAD; success generally means the character can move unimpeded, but failure increases the travel time by a single turn as the character is forced to bypass the obstacle. Examples include locked or damaged doors (Lockpicking, Electronics Operation (Security) or Forced Entry), damaged corridors that require clever movement to bypass (Acrobatics, Climbing, Jumping), or enemy patrols (Stealth or a combat scenario).

If a combat scenario occurs during such movement, the GM may wish to abstract it away with a single roll (Tactics, with bonuses or penalties based on how outnumbered or outgunned one side is), or play it out as a detailed scenario. Technically such a fight can last for up to 60 turns, but consider limiting the fights to know more than ten to twenty turns, so as not to bog down the game with scenarios within scenarios unless the fight is central to the game (such as the climactic duel between Tyrannic Cultist and True Communion templar for the fate of a world).

Chase Rolls

See GURPS Action 2 page 34, with the following update:

Chase Rolls meet in a Quick Contest. The outcome sets the range band at the start of the next round:

  • Victory by 0-4: No change. If your opponent had Advantage against you, they lose it. A pursuing craft with a stall speed must succeed by 0 or more to attack with fixed weapons.
  • Victory by 5-9: You may either gain Advantage against your foe or shift range by one range band. Characters who already had Advantage against their foe may Match Speed. If the character chooses to shift range, those who made a Pursuing Move or Move and Attack must reduce range while those who made an Escaping Move or Move and Attack must increase range.
  • Victory by 10+: You may Match Speed or shift range by one range band and gain Advantage (unless you already had Advantage, in which case, you Match Speed) or you may shift range by two bands. Shifting bands follow the rules for Victory by 5-9.

Voluntary Shifts: If both craft pursue one another and both involved agree, an additional range band shift can be freely granted. If both craft attempt to escape one another and both involved agree, either an additional range-shift can be granted or both can simply escape.

Hugging: If you Match Speed with a target that is at least 3 SM larger than you and you are within Collision range, you may declare that you are “hugging” that craft. If the vehicle is 6 SM larger than you, you are also inside its force screen and may ignore its DR for your attacks!

Remote Range: If using the optional remote range, shifting from remote to beyond visual or from remote to beyond remote requires two range-band shifts; furthermore, vehicles at remote ranges cannot be advantaged against other vehicles.

Escape

Escape occurs under the following conditions: the chased target successfully hides and elects to escape; the pursuer stops and declares their intent to resign the chase; the chased target exceeds the maximum range for attack given the current terrain; the chased target successfully shunts into hyperspace.

At the GM’s discretion, if the chase enters perfectly open terrain where further maneuvers are no longer relevant and only maximum speed matters, the GM can declare that the vehicle with the highest speed automatically wins the chase. For the chased target, this results in an escape. For the pursuer, this means that combat occurs at whatever range the chaser desires.

Static Maneuvers

See Page 34 and 35 of GURPS Action 2. Note that a static maneuver grants your opponents one free range band shift, and not victory on a chase roll! The static vehicle may still participate in the chase and may even gain Advantage, but their opponent will still gain their range-band shift!

A vehicle that has Matched Speed automatically loses its Matched Speed bonus if it engages in a static maneuver and its opponent does not.

Multi-Party Chases

In addition to the rules on page 34 of GURPS Action 2, you may treat all members of a single “group” as a formation. If a formation is attacked by a target that is not advantaged, any member of the formation may intercept the attack. Furthermore, a formation of two or more vehicles may benefit from tactical coordination. Finally, if any ship in the formation is equipped with an Area Jammer, all vehicles in the formation benefit from the Area Jammer.

Attacks

See GURPS Action 2 page 35 with the following clarifications:

Advantaged: If you pursued your opponent and you are Advantaged you may choose to attack any facing the GM allows.

Deceptive Attacks: Characters engaged in a chase may make deceptive attacks!

Facing: Any weapons you wish to attack with must have the option to attack in the facing you currently have. When attacking, you will attack the facing that your opponent declared. If you are Advantaged against your opponent, you may choose which facing to attack. If you have the ability to make a mobility pursuit or escape, the GM may allow you to attack normally forbidden facings. If you have the option to choose which opponent’s face you attack, this choice applies only to your attack (a different opponent might attack a different face).

Hugging: If you are hugging the craft, you can all the benefits of Matched Speed; if the hugged vehicle is 6 SM larger than you, your attacks ignore its force screen. If your target is hugging you, you may only attack with up to half of your turrets with the proper facing (and may not attack with fixed mount weapons at all), and all attacks are at an additional -2. If you wish to attack a target that is hugging another vehicle, apply the -2 to hit, and if your attack misses or is dodged, you will hit the hugged vehicle on a roll of (Hugged vehicle SM -3).

Matched Speed: If you have Matched Speed, you gain the benefits of Advantaged; Additionally, instead of using the Range (and Speed) modifier below, use the higher of the absolute value of the range penalty or your Stall Speed as your Range/Speed penalty. Finally, you may add accuracy to your attack even if making a Move and Attack (or any other attack that does not normally grant accuracy).

Movement: Gunslingers never suffer movement penalties for firing with hand-held weapons. Vehicle mounted weaponry never suffer a penalty for move and attack. Passengers aboard a vehicle suffer a -1 for hand-held weapons only; vehicle mounted weapons (such as stabilized turrets) suffer no penalty.

Plasma Flak: A Plasma flak turret can freely engage in “suppression fire” out to Extreme Range. At Extreme Range, they hit on a 1 + SM or less, while at Long or closer, they hit at 5 + SM or less; both have a Recoil of 1. Targets within Extreme range of a Flak firing target behave as though in rough terrain (-2 to handling) unless they are willing to take an automatic hit from the flak turrets. A failed handling roll in range of a flak turret results in an automatic hit by the flak turret. Flak turrets deal 6d×10 burn damage.

Relative Size: If a corvette fires at a fighter, apply a -5 to hit. If a capital ship fires on a corvette, apply a -5 to hit; if a capital ship fires at a fighter, apply a -10 to hit! Halve these penalties (rounded down!) if the weapon is noted as “light turret.”

Range (and Speed): Always use the highest of the absolute value of your range penalty, your own speed penalty, or your opponent’s speed penalty as your range penalty. In most cases, range will be the most important concern, but as very quick vehicles get closer to one another, their speed matters more and more. If your own speed bonus exceeds the absolute value of your range penalty, then you’re said to be “in collision range.”

Sensor Lock: Gain +3 to all attack rolls if you have a sensor lock. Increase this bonus to +5 if you have a targeting computer; sensor locks are assumed to be automatic if your vehicle has an Ultrascanner (or other active sensor) and your target is within range unless your target actively resists with an Electronics Operation (ECM) roll, or has not yet been detected.

Torpedoes: Torpedoes use Gunner (Torpedo), which defaults to Gunner (Blaster) at -4 and Artillery (Guided Missile) at -2. Because Torpedoes are relatively slow compared to missiles, they grant their target a +1 to dodge at Extreme and +2 to Dodge at Distant and may not attack a target farther than that.

Gunslingers and Ace Pilots: Most characters an only attack during the maneuvers stated on page 35 of GURPS Action 2. However, some characters have additional flexibility when attacking from a vehicle. Gunslingers may attack during the following maneuvers with hand-held weapons and Ace Pilots may attack during the following maneuvers with vehicle-mounted weapons:

  • No Attack Allowed: Disembark/Embark (Ace Pilots Only), Emergency Action, Hide
  • Attack without Accuracy: Mobility Escape, Mobility Pursuit, Move, Stunt, Stunt Escape
  • Attack with Halved Accuracy: Disembark/Embark (Gunslinger only!), Force, Move and Attack, Ram
  • Attack with Accuracy: Attack (or Move and Attack with Matched Speed)

Missile Attacks

When making a missile attack, ignore the above rules for deceptive attacks, range, sensor locks and targeting computers, and ace pilots never add their accuracy to the attack. Instead, when rolling to hit, add accuracy, size modifier, your opponent’s ECM penalty and half of your opponent’s speed modifier as a penalty (rounded up). Explosive weapons without armor divisors may attempt an “air burst” for a +4, and treat a miss by 1 on an explosive weapon as a “near miss”: a hit but with 1/3 damage and no armor divisor.

Missiles have a static dodge penalty of -3.

You may make a missile attack in any circumstances in which you can make a normal attack. Under circumstances where you would gain accuracy, you may instead fire a free missile in addition to any attack you might normally make.

Note that torpedoes are not missiles! They use Gunner (Torpedo) and are unguided!

Defenses

See GURPS Action 2 page 35. In addition, characters with Ace Pilot gain +1 to their first vehicular dodge if they chose a Stunt maneuver (Whether or not it succeeds, the erratic motion is enough to throw off your opponent’s attack).

Advantaged: If you attempted to escape and you gained Advantage, add +1 to all Defense rolls this turn.

High-G Dodge: If the vehicle has an acceleration of 40 or more, or has a move of 400+, it can make a High-G Dodge. This adds +1 to the dodge, but the pilot must make an HT roll. This HT roll gets +2 if the vehicle has a G chair or if the pilot wears a G-suit. On a failure, the pilot loses fatigue equal to the margin of failure.

Missile Defense

If the attack is a missile, apply a dodge penalty of -3. If the vehicle is equipped with a Tactical ESM, add +1 to dodge missiles. If the vehicle has a decoy launcher, they may use it to add a further +1 to dodge. Alternatively, the defender (or a passenger with access to jammer controls) may attempt to jam the missile. Treat this as a parry using (Electronics Operation (EW)/2), with a bonus equal to half the vehicle’s ECM rating, and +2 if the vehicle is equipped with a decoy launcher and uses it.

Decoy launchers have only so many charges. If the GM declares that the decoy launcher is “running low,” roll 1d6: the result is how many times you may benefit from the decoy launcher rules.

If the missile is explosive (without armor divisor) and the vehicle defends with a margin of 0, treat the attack as a “near miss”: a hit that inflicts 1/3 damage. If the attack was already a near miss, then it misses entirely.

Point Defense

Passengers who make a Wait and Attack (Point Defense) action may attempt to shoot missiles and torpedoes down before they reach their vehicle. Ignore range penalties and apply only size modifiers, speed penalties and sensor lock bonuses. Missile and torpedo speed and size modifiers may be combined into a single value:

Speed and Size modifiers by missile

  • 100mm “Light” missile: -16;
  • 160mm “Standard” missile: -16;
  • 400mm “Light” Torpedo: -11;
  • 640mm “Heavy” torpedo: -10;
  • 1600mm “Bombardment” torpedo: -8.

Force Screens

If the vehicle is equipped with a Force Screen, the DR provided by the Force Screen is hardened and ablative. Against plasma, plasma lance warheads, or shaped charge warheads, Force Screens ignore all armor divisors and eliminates the armor divisor for any armor underneath the force screen as long as the force screen has some DR remaining! Every point of damage a force screen absorbs reduces the total DR of the force screen by 1. The Force Screen automatically recharges to full power between maneuvers! Adjustable force screens may choose to double the DR of a single facing, at the expense of halving the DR of all remaining faces; the facing configuration of an adjustable force screen must be determined when your maneuver is chosen.

As an optional rule, Heavy Force screens (typically those on capital ships and military corvettes) should ignore all armor divisors from all attacks; this simplifies ablative DR calculation as the whole of the force screen must be eliminated to inflict any meaningful damage on the ship.

Force Screen recover their full DR between chase turns (once every 10 seconds in normal GURPS-scale combat).

Electronic Warfare

Detection and Ambush

Normally, ships will automatically detect one another at their maximum possible range. Only if a ship attempts to “sneak up” on or past another ship do we concern ourselves with stealth and detection. First, check to see if the scanning ship can detect the stealthy ship with its ultrascanner: roll Electronics Operation (Sensors) with a penalty equal to the stealthy ship’s ECM penalty (generally -4 for a distortion jammer and -4 for stealth) and a -10 if the ships are in a nebula; the Stealthy ship may resist, turning the roll into a quick contest between Electronics Operations (Sensors) (which still suffers the above penalties) and Electronics Operation (ECM). If the scanning ship detects the stealthy ship, it may engage combat at its preferred range (generally Beyond Visual). If the Stealthy ship wins, it may freely pass the scanning ship as long as it does not approach closer than Beyond Visual, or it may initiate an Ambush from Beyond Visual.

If a stealthy ship attempts to approach from closer than Beyond Visual must attempt to evade visual detection. Roll a contest between the scanning pilot’s Vision and the worst of the stealthy pilot’s Piloting and Stealth. Apply the following modifiers to the Vision roll: the ship’s SM as bonus, darkness penalties; -4 if the ship is equipped with a Dynamic Chameleon surface feature; -5 if in a nebula or an asteroid field and -10 if both are true; ignore range penalties or the bonus +10 for being “in plain sight” as these rules handle how close a target can get. If the stealthy ship is successful, it may pass or attack at up to Distant range, and for every four points of margin of success, it may approach one range band closer without detection.

If a ship successfully evades detection, it may initiate an attack at whatever range band allowed by their stealth result. This is an ambush.

During an ambush, the defenders may roll IQ; characters with Combat Reflexes may roll at +6; Those who fail may not act or defend on the first turn, while those who succeed may act and defend at -4. Characters with Danger Sense may roll IQ to detect the incoming attack; those who succeed may act and defend normally; on a critical success, they warn their allies of the incoming attack and all allies may act and defend at -4 (or normally if they also have Combat Reflexes).

Jamming and Targeting

Passengers may attempt to support the vehicle by actively jamming sensors. Normally a ship equipped with a tactical ultrascanner automatically locks onto any already detected ship. The target ship may resist by using a passenger action to roll a Contest of Electronics Operation (ECM) vs Electronics Operation (Sensors) with the latter roll penalized by the target ship’s ECM penalty. Success means that the enemy ship loses its “lock” on the target ship, which means it loses the +3 bonus for sensor lock (or the +5 for sensor lock with targeting computer) and may not attack the target with missiles. This effect only lasts for a single turn, but the passenger can continue to actively jam sensors.

If a ship is targeted with a missile, in addition to the operator’s dodge, a single passenger aboard the ship may attempt a defensive jamming roll using an installed Distortion Jammer Roll against half the passenger’s Electronics Operation (ECM) +2, with an additional +1 if the vehicle is equipped with a decoy launcher.

Damage

To make vehicles more durable, this system uses a variation of the Conditional Injury rules by Douglas Cole found in Pyramid #3/120, and combines it with the subsystem damage rules of GURPS Spaceships and the subsystem damage rules of GURPS Vehicles.

Wound Thresholds

Whenever a vehicle takes damage, compare the total damage against its HP; this determines its wound level. Once a vehicle has reached a particular wound level, it remains there until repaired. If a vehicle takes another wound equal to or less than its current wound level, the wound may accumulate. Roll HT once per additional wound; on a failure, increase the vehicle’s wound severity level by one (alternately, for simplicity, total up all additional wounds of this level from this attack, and roll HT at a penalty of one per additional wound). If the accumulation roll fails by a margin of 1 and the ship has a wound level that disables or destroys a system, disable or destroy a second system.

Scratch: Damage less than 10% of HP; ignore the wound entirely.

Minor Wound: Damage between 10% and 50% of HP; The vehicle has noticeable damage but still functions. Minor Wounds can accumulate.

Major Wound: Damage between 50% and 100% of HP; Disable one system. Major Wounds accumulate.

Crippling Wound: Damage between 100% and 200% of HP; Destroy one system. The Vehicle must immediately make an HT roll to remain operational (failure reduces it to minimum life support and power, etc). Crippling Wounds accumulate.

Mortal Wound: Damage between 200% of HP and 500% of HP; Destroy one system and immediately roll HT. Failure means the vehicle is destroyed. If this roll succeeds, roll HT to remain operational as per Crippling wounds. Mortal Wounds accumulate. If the vehicle has already taken a crippling wound, if it takes crippling wounds on subsequent turns, as an optional rule, the GM may destroy up to one additional system per turn.

Lethal Wound: Damage greater than 500% of HP; the vehicle is instantly destroyed.

Cinematic Injury

Mook Vehicles: For unimportant vehicles of unnamed NPCs, don’t worry about the full details of the wound threshold rules. If a vehicle takes a Major Wound, remove it. It is too damaged to continue. If it doesn't, there are sparks and it's damaged, and it moves on.

Just a Scratch: PCs may use the Flesh Wound rules on their vehicles. Spending a single character point reduces the severity of any injury to a Minor Wound; this can accumulate, but the result of any accumulation can only trigger a disabled system and nothing worse, even if the vehicle is Mortally wounded.

Disabled/Destroyed Systems

If a vehicle suffer a Major or Crippling wound, it may disable or destroy a system. Roll on the chart below to determine which system was damaged. An opponent can target a specific system by accepting a -5 to hit on his attack roll, in which case apply damage directly to that system without rolling.

If a system has already been disabled, roll against HT; on a failure, it is destroyed and the vehicle is considered to have suffered a Crippling Wound (this is in addition to the possibility of Wound Accumulation!). If the HT roll succeeds or the subsystem is already destroyed, the damage cascades to the noted subsystem.

3d Subystem
3 Fuel; Cascades to Power
4 Habitat; Cascades to Cargo.
5 Propulsion; Cascades to Weaponry
6 Cargo/Hangar Bay; No Additional effects
7 Equipment; Cascades to Crew/Controls.
8 Power; Cascades to Propulsion
9 Weaponry; Cascades to Equipment
10 Armor; Cascades to Fuel
11 Fuel; Cascades to Power
12 Habitat; Cascades to Cargo.
13 Propulsion; Cascades to Weaponry
14 Cargo/Hangar Bay; No Additional effects
15 Equipment; Cascades to Crew/Controls.
16 Power; Cascades to Propulsion
17 Weaponry; Cascades to Equipment
18 Armor; Cascades to Fuel

Disabled/Destroyed System effects

Armor: If disabled, any attacks to the ship’s armor chinks (-10) may ignore all DR; if destroyed, a large gap has been opened, and attacks targeting it (-5) ignore all DR.

Cargo/Hangar Bay: If disabled, half the cargo in the cargo bay are destroyed and vehicles are no longer able to launch or land. If this system is destroyed, all cargo and vehicles in the hangar bay are lost. In all cases, if the cargo bay or hangar pay contained explosive or dangerous items (GM’s discretion) roll HT. On a failure, the severity of the wound is increased by two levels.

Controls: If disabled, half of all control stations are lost and the ship’s handling is reduced by -2. If destroyed, the ship can no longer be controlled.

Equipment: If disabled, the attacker selects one of the following subsystems: the computer, the force screen, the ultrascanner, the comms system, or all ECM systems; this system is destroyed. If equipment is Destroyed, then all such systems are destroyed.

Fuel: If disabled, half of all remaining fuel is lost; if destroyed, no fuel reserves remain. If the fuel is volatile (ie, unrefined hyperium), then the vehicle must roll HT (at -2 if destroyed) or increase the wound severity by 2 levels.

Habitats: If disabled, life support is lost (this is not immediately lethal and the crew have hours of air left before circumstances become critical) and up to half of the crew are injured or killed. If destroyed, nearly all crew are injured or killed.

Power: If disabled, only half of all powered systems will operate on the vehicle. If destroyed, no power can be supplied to any system aboard the ship.

Propulsion: If disabled, halve the top speed of the vehicle; if destroyed, the vehicle cannot move.

Weaponry: If disabled, half of all weapons no longer work; if destroyed, no weapons aboard the ship function.

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