I wanted to try to write up my vehicles rules LBB style. Over all I liked what I did. But then I read Across the Bright Face and I realized I forgot a major part of any Traveller mini-game is trade offs and decisions to make. In any sort of classic adventure you have a finite supply of several resources you need to reach an objective. In Bright Face the resource was the ATV's power, the objective to reach the starport with a bunch of angry locals chasing you. You had the choice of using power to blast ATVs with your laser cannon or run.
My system didn't have that. You just shot at vehicles and they shot back. I got to thinking that besides power there were other trade offs in vehicle combat like visibility. Did you operate buttoned up or stick your head out to see what was going on? Anyway here are the rules without my color commentary and visibility rules.
Rules for Vehicle Combat
Vehicles have an armor class based on their construction as follows:
Civilian/thin skin vehicle (ground car, most aircraft, helicopters, grav speeders etc.): Mesh
Ruggedized (ATV, air/raft): Cloth
Paramilitary (GCarrier, AFV): Battledress
Besides its construction a vehicle has additional modifiers based on size and type:
ATV/AFV, GCarrier: -4 (5+ meters)
Air/Rafts, ground cars: -3 (3+ meters)
Hovercraft, grav speeder: -2
Thus an armored car for transporting dignitaries might be Cloth -3, a sportscar Mesh -3, A Gcarrier Battledress -4 etc.
People in the vehicle that are partially exposed (head out a hatch) would get -1 to be hit at Medium, -2 at long and -4 at very long. People in an open topped vehicle like an air raft only receive a -1 to be hit at long and -2 at very long range. A vehicle passenger or crewman standing in a hatch or hitching a ride on a deck does not get this bonus. A passenger or crew using a firing port or view slit is -4 to be hit.
A hit to a vehicle uses the small craft damage table from Book 2. Generally a hit disables a system. A drive hit means your ride is over. High performance vehicles like the speeder or ground car could take two or three drive hits with speed being reduced by 25%, 50%, and 75%. Computer hits would destroy or damage electronics.
Small arms that hit a vehicle have a 1 in 6 chance of damaging a system for each die of damage they cause, so 3 in 6 for most firearms. Optionally give the vehicle a hit whenever the damage inflicted adds to six. So if you manage to hit the AFV with a body pistol you have a 2 in 6 chance for it to notice. Hitting with both shots from an automatic rifle will get you an automatic hit of damage.
Ship lasers will do 1D of hits to a vehicle. Missiles (ship mounted or tac) will do 2D. Optionally apply the hits all to one system. A vehicle can take hull hits equal to its tonnage before catching fire, exploding or just being blown into confetti. Throw +10 to bail out of a vehicle, +appropriate skill, +1 if Dex is 9+. Success means the character bails out and manages to grab his gear. An '8' or '9' means you take 1-3D and grab a sidearm or other small item. If the roll is '7' or less you take 1-6D of damage and get out with just the armor on your back .
Weapons on a vehicle can be fired at people on foot. Human targets get a -1 to be hit, -2 from turreted weapons and can evade.
Vehicles can evade like characters. This only works vs. vehicular and similar weapons and the maximum minus equals the vehicle skill of the driver.
Starships and smallcraft are treated as paramilitary (Battledress +4) vehicles. Ship lasers do 1D hits to vehicles and starships at such close ranges. Missiles, artillery and rockets do 2D hits (because they explode on contact or very close.) Ship hulls ignore small arms doing less than 6 dice of damage. Weapons doing 7-8D of damage do one hit to a ship. Weapons doing 10D or more do two hits. Weapons doing 3D or more will puncture interior walls of a ship.
People in a vehicle suffer from reduced visibility. At short and close range people can stay out of view and attack. Spotting a person at short or close range in a vehicle requires a 7+ modified by vehicle skill. The spotters are penalized: exposed or open topped vehicle -1, if using a tv camera -2, -4 if using a gunport. Characters that are under cover get a further -4 to be spotted and moving characters get a +1 to be seen. Vehicles moving more than four bands or half their full movement impose a -2 to spot hidden ground forces. Starship crews using an Anti-Hijack program automatically spot people at short or close range and have no minus to to spot people out to very long range.