HOUSE RULES:
Critical Hits in D20 Starship Combat

by Martin Mosquera


"That's impossible, even for a computer!"
"It's not impossible. I used to bullseye womp rats in my T-16 back home, and they're not much bigger than two meters."


During combat the object (especially in STAR WARS) is to keep things moving quickly. Sometimes, however, it is necessary to know exactly how a ship or vehicle is damaged. At other times, you may need to aim for a specific part of the vessel -- a small thermal exhaust port, for example. Here are some rules for when you need to make that "one in a million" shot.


Called Shots

First, determine the size of the target area on the ship or vehicle, referring to the starship or character size charts (page 142 of the 3rd Edition Core Rules). The table below indicates the modifier to hit and how many hull points of damage (expressed as a percentage of the ship or vehicle's full original hull points, rounded down) are required to completely destroy the component. The vessel's DR is usually added to this, but the game master may rule that the target area is only partially armored, or not at all. (This is often the reason someone is shooting at that spot in the first place.)

Shots which hit the target are considered to do negligible damage to the rest of the vessel, aside from the possible effects of the component's destruction. Shots which miss due to the higher difficulty, but which would normally hit the ship or vehicle, strike some other part of it and damage is applied as usual.

Example: A bounty hunter attempts to shoot out the headlights of an approaching speeder. The speeder has 35 hull points and a DR of 5. The headlight is 20 cm across; according to the character size chart, this makes it a Fine target. Per the table below, a called shot against the headlight is at +20 difficulty and it takes 8 hull points to destroy (10% of 35, rounded down, or 3, plus DR 5).

Target Size Difficulty Modifier Hull Points to Destroy
Colossal +4 90%
Gargantuan +8 80%
Huge +10 70%
Large +11 60%
Medium +12 50%
Small +13 40%
Tiny +14 30%
Diminuitive +16 20%
Fine +20 10%


Critical Hits for Vehicles and Starships

Critical hits occur on a natural 20. If the critical hit takes the target to or below 75% of its original hull points, consult the Light Damage critical table; to 50% or below, the Heavy Damage table; and to 25% or below, the Severe Damage table. Ships and vehicles with 0% of their hull points are, of course, destroyed.


Vehicles

Light Damage
Roll (d6) Result
1-3 Vehicle loses maneuverability, +5 to all maneuvers.
4 One onboard weapon hit and destroyed, gunner takes 1d4 wound points.
5-6 Vehicle loses 1 speed category level.

Heavy Damage
Roll (d6) Result
1-3 Vehicle loses maneuverability, +10 to all maneuvers.
4-6 Vehicle can now only travel at its cautious speed.

Severe Damage
Roll (d6) Result
1-2 Powerplant destroyed. Ground vehicles coast to a halt; air vehicles crash (a controlled landing may be possible, see 3 below).
3 Powerplant begins to overload and will explode in 1d6 rounds, completely destroying the vehicle. Pilot must stop or land the vehicle: DC 15, plus any other modifers from damage.
4 All onboard weapons destroyed, all gunners take 3d8 wound points.
5-6 Vehicle is completely out of control. Automatic failed maneuver. Pilot must attempt to regain control: DC 20 plus any other modifiers from damage.


Starships

Light Damage
Roll (d6) Result
1 Ship loses maneuverability, +5 to all maneuvers.
2 One weapon destroyed, gunner takes 1d4 wound points.
3 One onboard system rendered inoperable due to power failure.
4 Hyperdrive damaged, can only be used for one jump. Fixed when hull points are restored.
5 Shields regenerate at half capacity.
6 Sublight engines damaged, -1 movement category.

Heavy Damage
Roll (d6) Result
1 Ship loses maneuverability, +10 to all maneuvers.
2 Fire control lost, entire arc of weapons off-line.
3 Weapons in one arc are destroyed, gunners take 2d4 wound points.
4 Hyperdrive damaged, bleeding energy (hazard in engineering), can only be used for 4d6 hours before burning out completely.
5 Shield generators overloaded, shields cannot be restored. Generator must be repaired.
6 Sublight engines damaged, -1 movement category; if "Stopped", ship is drifting helplessly in the direction of its last powered movement.

Severe Damage
Roll (d6) Result
1 Sublight engines destroyed, ship is dead in space.
2 Reactor core is going critical; it must be shut down (DC 20) or it will explode in 2d6 minutes, destroying the ship.
3 Hyperdrives disabled, ship cannot enter hyperspace.
4 All power to weapons is cut off.
5-6 Structural overload: ship loses 1 hull point per round until it is destroyed. DC 25 to hold the ship together, modified by the ship's size.


Optional Shield Rules

If a critical hit is rolled on a ship with shields protecting it, roll again. If the second roll on a d20 also hits, the attack has found a weak point in the shields; roll damage and apply it directly to the ship's hull points. If the second roll is a miss, apply damage to the shields normally. If the second d20 roll is also a natural 20, roll for a critical hit on the ship.

Shield energy can be doubled either to the front or to the back, but this leaves the other arc with no protection. Switching settings requires one round.

A repair roll can be made to restore shields in combat:

DC To Restore
10 10%
+5 25%
+10 50%
+15 65%
+20 75%
+25 100%



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