A Basic Ship Combat System (by Merrick Burkhardt, with stuff yanked from HG, BL, BR, and Don Perin's beta combat system. Along with help from Guy, James, and ideas lifted from the beta list traffic generally. When I have a real version I'll make sure to get all the names in :-) Version 0.5, 7 July, 1996 Contents: --------- I. Intro 1. Scale a. Time b. Distance c. Units 2. USDs 3. Turn Sequence II. Movement 1. Vectors 2. Movement 3. Evasion 4. Facing (Adv) 5. Missile movement III. Sensors 1. Overview 2. Active v. Passive 3. Sensor Task Resolution IV. Weapons Fire 1. Types of weapons a. Lasers b. PAWs c. Meson Guns d. Missiles 2. Normal, Opportunity, and Anti-Missile Fire 3. To-Hit a. Eligibility b. Fire Table c. DMs 4. Direct Fire Screens a. Sandcasters b. Meson Screens c. Black Globes 5. Anti-Missile Systems a. Lasers b. Dampers (turrets and screens) c. Sandcasters V. Damage Resolution 1. Structure Damage 2. Armor Reduction 3. Damage Allocation a. Damage Tables b. Table Results VI. Damage Control I. Intro ========= BSCS, when not looking for a sexier name, is intended to provide a basis for space combat in Traveller for player character ships to full fleet engagements. All combat, regardless of the number of units, or the size of the individual units themselves, will share certain features. Among them are scale, a movement system, and common distances of fire control locks, and weapons fire. Differences in complexity will reside for the most part in damage allocation, though PC ships might choose to use more skill based tasks within the combat where NPC ships would be assumed to function at the base crew level that the game assumes. These rules are full of abbreviations, and while I have noted most at the time of their first use, I've provided a list at the end of all of them. 1. Scale a. Time Turns are 30 minutes long. Actions are conducted throughout the course of the turn. b. Distance One hex is 30,000km (0.1 Light second) across. c. Units All units are represented as Task Force (TF) counters to hide their true composition until detection. A TF is a group of ships operating together. TFs may have up to the Fleet Tactics skill level of the controlling player. Units types for TFs are ships, craft, and drones. Missiles are a special case. A group of missiles launched by a single launcher vs. a single target is called a Spread, and marked with a single counter. 2. USDs All unit types are described by their Universal Ship Description (USD). Missiles have an abbreviated USD sheet. 3. Turn Sequence Initiative Phase Sensor Phase Operations Phase Movement Opportunity Fire Normal Fire Missile Movement Phase Missile Attack Phase Turn Record Phase ================ Initiative Phase ================ Roll for initiative on 1d6. Use Tactics skill as a DM. High roll has initiative for the turn. The player without initiative launches, recovers, or reconfigure Task Forces (TFs). The player with initiative then does the same. Launching: As per BR (include fighters with BRs). ================ Sensor Phase ================ Players decide on the active or passive status of each TF secretly and announce them simultaneously. Sensor tasks are then resolved by TF. ================ Operations Phase ================ Players take turns conducting movement and fire by TF. The player with initiative chooses who moves the first TF. If a player moves all his TFs, then the other may move all his remaining ones. During movement, an enemy TF that is assigned Opportunity Fire may chose to attack the moving TF at any point in its movement. Each TF may conduct Movement, and Fire operations in any order during its operation round. ====================== Missile Movement Phase ====================== Players alternate moving missile spreads. The player without initiative moves first, and movement alternates until all spreads have been moved. ==================== Missile Attack Phase ==================== All defensive actions vs. missiles are announced by TF, and resolved. Although fire is resolved in order, all results are considered simultaneous. ================= Turn Record Phase ================= The turn has ended. II. Movement Task Forces (TFs), individual spacecraft, and missiles all move in the same way. 1. Vectors Movement in BSCS is vector based. A vector is the combination of an object's velocity and its direction of movement. To simulate this, all spacecraft (etc.) are represented by 3 markers. One for the position it is in this turn, one where it was last turn, and one where it will be next turn assuming it doesn't change course. They are called the Present, Past and Future position markers. 1a. Diagram 2. Movement A spacecraft's g-rating is the number of hexes that it may alter its position in a turn. To do this, move the Future position marker by the number of hexes desired (don't exceed g-rating!). Then move the Past marker to where the Present marker is, and the Present to the new position of the Future marker. Now note the pattern between Past and Present, and move the Future marker in the same pattern (they should be in a line, equally spaced). The use of 1g for a turn is called a g-turn. For ships with reaction drives, or missiles, fuel is listed as the number of g- turns that a ship may use before refueling. 3. Evasion Gs not spent on movement may be spent on Evasion. Standard evasion results in a +1DM against attacks on the evading spacecraft per evasion g spent. Piloted craft may attempt to increase the effect of this through the pilot's skill. To do this, roll 2d6 vs. pilot skill. If the task succeeds, then you may double the DM for evasion gs spent. If it fails, the result halves the Evasion DM. 4. Facing (Adv) Need some Facing info. 5. Missile movement To simulate the target seeking abilities of missiles, they will move after all non-missiles, but will still follow the same principles. Missiles will move in such a way as to have their Present position markers on the target's Present position at the end of their movement. Some missiles have to close to very close ranges to damage their targets. These weapons have to not only reach the target hex, but have a g-rating, and g-turns remaining to counter target evasion. The extra gs required are equal to the target's Evasion DM (usually the evasion gs spent). Missiles may use left over gs for evasion if they have any that can be used. Their Evasion DM is the gs used for evasion divided by 5. (?) III. Sensors Active Sensors Active sensors detect targets by sending out pulses of energy, such as radio waves or lasers, which then bounce off their targets and back to the sensor. The time that it takes the pulse to return, the shift in frequency of the pulse and a myriad of other factors can be used to determine the distance and direction of the target, its motion relative to the sensor and other detailed information about the target. The two main drawbacks of the active sensor are that it broadcasts its own presence by filling space with pulses of energy, and that it requires a lot of power to generate pulses powerful enough to bounce back from very distant targets. Passive Sensors Passive sensors do not betray themselves by emitting energy. Rather, they detect targets by sensing the enrgy given off by those targets. Passive sensors are typically less effective than active sensors in therms of absolute range, but are more tactically useful for ships that wish to remain unnoticed. Most ship USDs have a Sensor Rating. This rating is the Short Range (SR) of the sensor listed. If a bogey is within the SR of the sensor, it makes the Lock attempt at the Short Range difficulty level. Medium, Long and Extreme ranges are multiples of the SR as follows: Range Range Band Actual ----- ------ Short SR Medium SR*2 Long SR*4 Extreme SR*8 Example: A bogey is 37 hexes away from a ship attempting a Lock with a SR6 PEMS. The bogey is at Extreme range for this sensor (S6-M12-L24-E48). Another ship in the TF trys with its SR16 AEMS. The bogey is in the Long range band for this sensor. All friendly ships in a single TF with functional commo share FC info (Locks). Note that if they don't have tight beam gear they must break radio silence (go active) to do so. Ships outside a TF may also share FC info, but they must roll a communications task. If they are in communications, then the benefit is a DM on the Lock task of the ship. This is called a "hand-off." 1. Active v. Passive At the beginning of the Sensor Phase, all ships must announce their Active or Passive status simultaneously. Any TF using a non- tightbeam active device must declare as "active" and give the SR of the active device when asked for DMs. 2. Sensor Task Resolution Sensor attempts are made during the Sensor Phase of the turn. All ships in a TF may use any or all of their sensors as long as no given sensor makes more than one attempt per target. Sensor roles use DMs that are a function of the sensing ship, and DMs which are a function of the target ship. The target ship player must calculate all the DMs that apply to his ship, and give them to the sensing player as a total. He must also give the SR of the longest range active device that is in use during this Sensor Phase that apply to the sensor task (see list below). The sensing player uses these, as well as his SR and DMs to determine the final roll required. The target player gives his TL and jammer SR if there is a jamming attempt. Knowing the active or passive status of the attempt the target player gives the sensing player adjusted roll required. The sensing player modifies this for range (+1 Med, +2 Long, +4 Extreme) and makes the roll using the final roll required. You may consult the range table instead of the range DMs above. Range Roll Required ------ -------------- Short Size or less Medium Size-1 or less Long Size-2 or less Extreme Size-4 or less DMs for Active Sensor Lock attempts: ------------------------------------ Target Folding array deployed, -4 Jammer-sensor TL difference In Jammer's SR, +4 (There might be a Jammer task in Adv. game) In Jammer's MR, +3 In Jammer's LR, +2 In Jammer's ER, +1 Target BG, +1 per USD (10% flicker rate) Target has Masking, +3 Locked last turn or hand-off, -4 DMs for Passive Sensor Lock attempts: ------------------------------------- Target Powered Down +4 Target using Mdrive, -3 Mdrive is a reaction drive, -3 (additional) Target drive is Stern-on, -4 Target BG, +1 per USD (10% flicker rate) Target has Masking, +3 Locked last turn or hand-off, -4 If you had a Lock last turn, or if another ship or sensor is "handing-off" the Lock, you may use the DMs. Passive Sensors used to detect targets that are active are allowed to use the combined SRs of the Passive sensor making the attempt, and the Active device broadcasting. Active devices include: Radar, AEMS, Ladar(if it had a Lock on the sensing ship last turn), MFDs(if used against the sensing ship last turn), Radio commo, or Jamming. Example: A SR4 PEMS is attempting a Lock on a target using a SR10 AEMS 27 hexes away. The sensing ship gets to calculate range based on a SR of 14. The target is then in Medium range for the sensor roll. If the taregt were not active, the attempt would be at Extreme range instead. IV. Weapons Fire 1. Types of weapons Weapons are mounted in Turrets, larger turrets called Barbettes, huge steerable mounts called Bays, and large non-steerable mounts called Spinal Mounts (also Parallel and Janus Mounts). Steerable weapons are then grouped into Batteries that are linked by fire control to shoot at the same target. Spinal mounts, and smaller non-steerable weapons are always considered as a single Battery each. a. Lasers Lasers are grouped into batteries and have a USD rating for the entire Battery. Lasers use focused beams of coherent light to impart energy to enemy targets over a very small area. Relative to other long-range beam weapons,lasers have good penetration performance, but generate less explosive force and damage. Lasers are less affected by ship armor, but can be blocked by sandcasters and black globes. b. PAWs PAWs are one weapon per Battery. Particle accelerators accelerate subatomic particles - almost exclusively neutral atoms such as hydrogen - to very high speeds at enemy targets.These have less penetrative ability than do lasers, but generate a much greater explosive force. Unlike lasers, particle accelerators require long accelerator tunnels, and so most are built as spinal mount weapons, running the entire length of the ship. Particle accelerators can be blocked by ship armor, sandcasters, and black globes. c. Meson Guns Meson guns also accelerate subatomic particles at enemy targets. But in this case the particle is a meson, which does not interact with matter, and therefore passes through all objects without resistance. However, the meson has only a short life, after which it decays into other more destructive particles. By accelerating the meson to relativistic speeds, its subjective passage of time slows, and its decay is delayed. By timing the decay to occur as a group of mesons pass through an enemy ship, powerful explosions can be created within enemy targets without having to penetrate the armor. Meson guns may only be blocked by meson screens and black globes. d. Missiles Missiles are small, unpiloted spacecraft with explosive warheads. The warheads can use conventional high explosives to spread lethal shrapnel, nuclear explosives, or use a nuclear explosion-pumped X- ray laser shot. Missiles attempt to maneuver as close to their target as possible before detonating. Missiles may be blocked by sandcasters and, for nuclear warheads, dampers. Laser batteries on the target ship may also engage missiles as a defensive measure. Missile launchers and controllers are listed on a ship's USD. This shows how many missiles can be fired at a time, and how many may be controlled. Missile launchers fire a "Battery Round" that forms a Missile Spread. A standard turret fires 2 missiles, so the Battery Round is a 2-missile spread. A 50ton Bay might fire a 36-missile spread. Like other weapons, these spreads have USD ratings to represent their combat performance. The missile USD Form will also list DMs used on the to-hit and damage rolls based on specifics of the missile. The form will also list the modifier that anti-missile (AM) fire uses against the missile as well (this is a function of missile design and how close it must approach the target to attack). Missiles from a given launcher launched at a given target stay in a single spread. Any missile launcher may launch and control fewer missiles than it is rated for at a given target. Missiles designed will be listed with individual stats, as well as a USD for possible Battery Rounds (by USD). Sample missiles: TL15 12g12 500kt Det-laser Dam: 7 To-hit:+0 DamDM:+0 (laser) AMDM:+0 # of missiles:1 Controlled Bat. Dam. Round USD ----- --- 1 7 2 10 (Turret) 3 11 4 12 5 13 (Barbette) 6 14 7 15 8-9 16 10 17 11-12 18 13-14 19 15-16 20 17-18 21 19-21 22 22-25 23 26-28 24 29-32 25 33-36 26 (50T Bay) 37- 72 32 (100T Bay) TL15 12g12 Near Prox KKM Dam:* To-hit:+4 DamDM:-CV/2 AMDM:-4 # of missiles:* S/FIM P1 *Battery Round Table(for this missile) Bat. Dam. Round USD ----- --- 1 2 2 3 (Turret) 3 4 5 7 (Barbette) some numbers here 36 15 (50T Bay) some more numbers :-) 72 19 (100T Bay) And so on. As missiles are reduced, the spread's USD will go down. I would suggest printing missiles on index cards with the reduction table on the back. 2. Normal, Opportunity, and Anti-Missile Fire Normal Fire is conducted during the Operations Phase by the player moving his TF. If a player chooses not to fire weapons from the ships in a TF during a given Operations Phase, he may designate them as waiting for Opportunity Fire or for Anti-Missile Fire (AM). Opportunity Fire is conducted during an enemy movement phase. A non-moving player may chose to attack the moving TF with any TFs assigned Op. Fire. Anti-Missile fire is conducted during the Missile Attack Phase of the Turn. In the Basic Game, AM fire is announced after missiles roll their to-hit rolls (the fire control can tell which ones won't hit). For Advanced play, any missile that detonates at det-laser ranges must have AM fire assigned before the to-hit roll is made. Missiles that must come inside det-laser range may be targetted after the to-hit is made. The trick is that you won't know which is which until the det-lasers explode. AM tasks must then follow this pattern: Some AM fire is designated to each (some) spread(s). Surviving det-laser ranged weapons explode. Closer ranged missiles roll to hit. Missiles that hit are assigned remaining AM Batteries. 3. To-Hit a. Eligibility Ships can sometimes only bring a percentage of their weapons to bear at any given target. In Basic play, the number of Batteries that may fire at a target is given by the following table: Ship Batteries Size Bearing ------- ---------- =