The Eight Worlds -- Space Combat
     That terrible drama upon which so much else depends

Overview: The Basic Turn Sequence

Space combat in the Eight Worlds takes place using a vector movement system, with rules for the effects of direct-fire weapons such as lasers and short-range hyper-velocity missiles, the effects of explosions, and damage control. The original rules work well in two dimensions on a classroom- sized blackboard or whiteboard. By reducing the scale, it's possible to manage them on a smaller surface. The system could in principle be extended to three dimensions using a large monitor and the appropriate display software, but to the best of my knowledge, no one has tried this yet.

Turn Sequence
The basic turn sequence is described below.

  1. Move. Zoom
  2. Fire. Blam!
  3. Damage Control: that exciting "Fix the hull!" phase

The detailed turn sequence is somewhat more complicated, since it must include special rules for high-acceleration vehicles such as torpedoes, gunboats, missile boats, and fighters. I will write this up as time permits. Individual phases are described in the following sections



Movement

As noted above, the Eight Worklds uses a vector movement system similar to that used in the original Traveller rules and many other science fiction games. During each combat turn, a ship moves in the distance and direction determined by its velocity vector. A ship may use its drives to change it's velocity vector.

Units of Measurement
During one Combat Turn, a ship that accelerates from rest at 1 g will reach a velocity of two Velocity Units and travel one Distance Unit. (Remember from basic physics that d=(1/2)*a*t2. That (1/2) is important!) One Distance Unit is 1000 km. If one applies Newton's Laws and performs the calculations, one discovers that one Combat Turn must last 447.2136 s (7.45356 minutes) while one Velocity Unit must be 0.4472136 km/s. In practice, no one can remember these seemingly arbitrary numbers or would even want to, so we pretend that the actual values are.

  • 1 Distance Unit - 1000 km
  • 1 Velocity Unit - 0.5 km/s
  • 1 Combat Turn - 6 min (10 space combat turns/hr)

The differences between these and the correct numbers are small, if it bothers you, you can always pretend that the Eight Worlds uses slightly different definitions for seconds and kilometers.



Combat Tables

This is a work in progress. It will be edited, corrected, added to, and explained in the future. In the table below, ranges are in Distance Units(1000 km), numbers are the modified gunnery roll on 2d6 needed to hit (see below), and numbers in parantheses, when present, are points of damage for weapons that deliver more than one point. In general, ships can take 4pts/tonne before they are disabled, so a hit at 8,000 km from the tri-mount 'Long 6' of a Cruiser will deliver 30 points of damage, which will disable but not destroy a 600 tonne Destroyer (24 pts).

The Modied Gunnery Roll
The modified gunnery roll on 2d6 is as follows

Modified roll = Actual roll + Targeting + Silhouette - Evasion - Shields

Targeting is accomplished using Gunnery skill or computer control. To use Gunner skill, the turrent must be equipped with working sights and manual controls. Standard computer control is +3. This can be improved using Ranging Gear. Gunnery skill and computer control are seperate forms of targeting and cannot be combined. In practice, this means most ships are +3 to hit.

Evasion is accomplished using Pilot skill or... you guessed it... computer control. The maximum possible evasion bonus is limited by the ship's acceleration as follows

Accel 1g 2g 3g 4g 6g 8g 10g 14g(1) 18g 22g ...
Evasion -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 ...
(1) At Eight Worlds tech levels, even the most powerful torpedoes can't pull much more
     than 14 g's, so the higher values are included only for entertainment purposes.

In practice, the vast majority of starships pull 4 g's, have a silhouette modifier of 0, and are too small to carry shields, so most combats occur with a modifier of Gunnery+Evasion = -1 (e.g. ships are -1 to be hit).


Direct Fire Weapons -- Not yet reviewed and corrected
Weapons of the Eight Worlds Hypothetical Superweapons Alien Weapons?
 
Range
1cm
LLC
2cm
CR
2cm
LC
4cm
Long 6
6cm
Long 10
8cm
Long 15
12cm
Super 20
 
Range
20cm
Super 40
100cm
VLRC
2cm
Optical
2.5cm
Long 2
3cm
Long 3
0-5 6 4 6 6 (10) 6 (20) 6 (40) 6 (100) 170-210 8 (200) 8 (1000) 5 6 (4) 6 (5)
5-10 10 8 6 6 (10) 6 (20) 6 (40) 6 (100) 210-290 10 (120) 8 (600) 7 6 (4) 6 (5)
10-20 12 10 6 6 (10) 6 (20) 6 (40) 6 (100) 290-370 10 (60) 8 (300) 8 5 (3) 5 (4)
20-30 14 12 8 6 (10) 6 (20) 5 (40) 4 (100) 370-500 12 (30) 8 (150) 10 7 (2) 7 (3)
30-50 - 12 8 8 (8) 8 (20) 7 (40) 6 (100) 500-700 14 (15) 8 (75) 12 9 (1) 9 (2)
50-70 - - 12 8 (6) 8 (16) 8 (40) 8 (100) 700-900 - 10 (50) 14 10 (1) 11 (2)
70-90 - - 14 10 (4) 8 (12) 8 (30) 8 (80) 900-1300 - 10 (50) - 13 (1) 12 (1)
90-130 - - - 12 (2) 10 (8) 8 (20) 8 (80) 1300-1700 - 10 (50) - - 14 (1)
130-170 - - - 14 (1) 12 (4) 10 (12) 10 (40) 1700-2100 - 10 (50) - - -
170-210 - - - - 14 (2) 12 (6) 10 (20) 2100-2900 - 12 (50) - 13 (1) 12 (1)
210-290 - - - - - 14 (3) 12 (10) 2900-3700 - 14 (50) - - 14 (1)
290-370 - - - - - - 15 (5) 3700-5000 - - - - 14 (1)

Critical Hits
Every hit has a chance of causing critcal damage. The chance and number of critical damages that occur depends on the power on target and the precentage damage after this hit has been accopunted for. Tables for chance and number of criticals are given below.

Critical Hit Chances and Multipliers
Percent
Damage
Critical if
(on 1d6)
Multiplier
0-20 6+ x1
20-40 5+ x1
40-60 4+ x2
60-80 2+ x3
80-100 1+ x4
    Power vs #Criticals
Power on
Target
Number or
Criticals
0-20 1
20-40 2
50-100 3
100-200 4
200-300 5

The tupe of critical is determined by rollong two dice: one for hull region and another for type. The following tables list types of critical damage and the skills needed to repair them.

1 Avionics
Item Skill
LRS Elec-2
Sensors Elec
Avionics Elec
Commo Elec-2
Comp Comp
Bridge Mech
  2 Weapon
Item Skill
Sights M, G
1 tube M, G
2 tube M, G
3 tube M, G
Manual M, G
Gunner ouch
  3 Fwd Hull
Item Skill
Cooling N, M-2
Traverse Elec
1 Crew ouch
2 Crew ouch
3 Crew ouch
Fire cntrl E-2
  4 Midships
Item Skill
Shields E
Fwd bay $$$
Fwd bay $$$
Airplant M
Gn pwr E+2
J core N
  5 Aft Hull
Item Skill
L Jack M-2
Aft bay $$$
Aft bay $$$
Fuel Fuel
Controls E
x2 & reroll -
  6 Engineering
Item Skill
Jumper N
Drive N
Drive N
Fusor N
Conv N
E Room Mech

These criticals and their effects are described below

Type Effect
LRS One randomly chosen Long Range Sensor system (there may be only one) is disabled. These detect and track hyperspace jumps.
Sensors One randomly-chosen sensor box is disabled. Consult the ship's avionics list to determine the effects
Avionics One randomly-chosen avionics or sensor box is disabled. Consult the ship's avionics list to determine the effects
Comp One randomly-chosen computer box is disabled. Consult the ship's avionics list to determine the effects
Bridge The Bridge is hit! Wham! Incandescent shrapnel sprays across the bridge, causing another Avionics critical (which cannot be another Bridge hit) and exposing every member of the flight crew to a 3d6 fragmentation and a 3d6 concussion attack. Aren't you glad you're wearing armored vacc suits? And aren't you glad you have an armored bridge? Um, you do have an armored bridge, don't you?
Sights Gunsights in one randomly-chosen turret are disabled. Multiple points are required to disable a 'Long' turrent.
1 tube One tube in one randomly-chosen turret is disabled. Multiple points are required to disable a 'Long' turrent.
2 tube Two tube in one randomly-chosen turret is disabled. Multiple points are required to disable a 'Long' turrent.
3 tube Three tubes in one randomly-chosen turret is disabled. Multiple points are required to disable a 'Long' turrent.
Manual Manual controls in one randomly-chosen turret are disabled. Multiple points are required to disable a 'Long' turrent.
Gunner The gunner in one randomly-chosen turrent is hit! Wham! Incandescent shrapnel sprays across the tiny compartment, exposing gunner to 5d6 fragmentation and a 5d6 concussion attack, one of which is certain to penetrate even an armored vacc suit. But gunners are born to die.
Cooling Cooling system in one randomly-chosen turret is disabled, tubes become Pulse (-1) rather then continuous wave.
Traverse Traversing gear in one randomly-chosen turret is disabled, turret become Forward Firing (-1).
1 Crew The Crew Section is hit! Wham! Incandescent shrapnel sprays across two adjacent staterooms and the adjoining companionways, exposing everyone inside to a 4d6 fragmentation and a 4d6 concussion attack and causing a faint set of carbon lines to show up in the emissions spectrum of the hit.
2 Crew The Crew Section is badly hit! Wham! Incandescent shrapnel sprays across four adjacent staterooms and the adjoining companionways, exposing everyone inside to a 4d6 fragmentation and a 4d6 concussion attack and causing a nice set of carbon lines to show up in the emissions spectrum of the hit.
3 Crew The Crew Section tets hammered! Wham! Incandescent shrapnel sprays across six adjacent staterooms and the adjoining companionways, exposing everyone inside to a 4d6 fragmentation and a 4d6 concussion attack and causing a brilliant set of carbon lines, water vapor, and perhaps a bit of hemoglobin to show up in the emissions spectrum of the hit.
Fire cntr Remote fire control for one randomly-chosen turret is disabled. Turrent must be aimed by hand using Gunnery.
Shields Shield generator is partially disabled (-1). If you don't have one, you get off scott-free.
Fw bay Forward cargo bay is hit and 10 tonnes of randomly-chosed cargo, spare parts, or empty space are destroyed.
Airplant Air recylcing system is disabled. We'll worry about that after the battle.
G pwr Power to one randomely-chosen gun turret is knocked out. Alas.
J core Hyperdrive core is disabled. That's no hyperspace jumps for you!
L jack Landing jacks, lifters, and/or hear shield are damaged. Which one? We'll find out during re-entry and landing.
Af bay Aft cargo bay is hit and 10 tonnes of randomly-chosed cargo, spare parts, or empty space are destroyed.
Fuel A fuel cell is hit and 10 tonnes of randomly-chosed fuel or empty space are lost. Hope you have extra!
Controls Flight controls are damaged and ship can no longer perform evasive action or use its evasion bonus.
x2 Double-damage and roll for another critical! Fortunately this can only happen once. Which is more than enough.
Jumper Hyperdrive is disabled. But you didn't want to jump away, did you?
Drive One drive unit is disabled. If you had more than one, you can stil use the others.
Fusor One fusor is disabled. If you had more than one, you can stil use the others.
Conv Convertor for one fusor is disabled. Fusor works fine, but can't produce power.
E room The Engine room is hit! Wham! Incandescent shrapnel sprays across... but you read that part already. Roll another Engineering critical (which cannot be another Engine room hit) and members of the engineering crew are exposed to a trifling 3d6 fragmentation and 3d6 concussion attack. Yes, it's a cushy job down in the engineering section. Unless one of the fusors or drive units blows up.


Damage Control

After a ship has been hit, the crew can attempt to repair the damage. In general, if a ship is pulling N g's, it takes a modified roll (2d6+skill) of 9 of 8+N, whichever's larger to fix a point of damage. Details will follow when I have time to transcribe them.



Examples

Eventually there will be some examples of combats here. This will take time.



Last modified: 20 January 2010