Star Fleet Battles
Inertial Vector Movement

This is a half-baked but vaguely workable attempt at a vector movement system for SFB. Unless otherwise stated, all rules are as normal SFB. It replaces most of the movement rules.

It will probably do your head in and play all manner of havoc with seeking weapon balance.


(CJD1.11) MOVEMENT VECTOR: Each unit has a movement vector consisting of a number of hexes per turn in one or two directions referenced to the hex grid. This is expressed as, for example, 19D or 3A+9B.
Speeds are measured on a 32-impulse basis, as in normal SFB.
(CJD1.111) If a unit has a vector in two directions, they will be adjacent (eg 8E+5F). Movement in opposing directions (eg 4A+2D) cancels out (here to 2A). Movement in directions 120° apart (eg 9A+6C) is refactored to result in the direction between (here 3A+6B).
(CJD1.12) FACING: The facing of a unit is independent of its movement vector; a unit may go forward, sideways or backwards. Facing determines the direction of acceleration and deceleration.
(CJD1.13) SPEED: A unit's speed is the sum of its two movement elements, and determines when it moves. For example, 8B+12D has a speed of 20 and moves on the Speed 20 column of the impulse chart.
(CJD1.131) A unit is not limited to speed 31. There is no limit to the speed a unit may travel (but see (CJD1.61)).
(CJD1.14) HOW TO MOVE: In the course of 32 impulses, a unit will move its total vector. When the unit moves, the owning player may move it in either element of its vector provided that it does not move twice in the lesser remaining element. For example, 3B+5C might move CCCBCBCB, BCBCBCCC or BCCCCBBC but not BBCBCCCC
(CJD1.141) After acceleration, restart the count with the new total vector.
(CJD1.142) A unit may sideslip as normal.

(CJD1.21) ENERGY ALLOCATION: In EA, a unit may allocate some power to movement (up to any quantity of warp and 1 impulse power). This can be used for acceleration or rotation, unplotted. More may be added from reserve power at any point; no special rules apply.
(CJD1.22) RESERVE POWER: More movement energy may be added from reserve power at any point and used for acceleration or rotation; no special rules apply.

(CJD1.31) ENERGY REQUIREMENT: 2 points of warp movement or 1 impulse power accelerate the unit by 1 hex per turn in the direction the unit faces at that moment. So a normal 30 warp ship can accelerate by 16 per turn, including impulse, if in a straight line.
(CJD1:312) Acceleration in reverse costs 4 points of warp movement or 1 impulse power per hex of movement.
(CJD1:313) Only 30 points of warp movement and one point of impulse power can be used in a single turn.
(CJD1.32) APPLICATION: A unit can apply any or all allocated acceleration on any impulse(s), but not within 8 impulses of any other acceleration (6 impulses for Nimble units). After each acceleration, forget any remaining moves left from the last segment.
(CJD1.3x) EMERGENCY DECELERATION: ED does not stop a unit. It merely converts unused movement energy to shield reinforcement as normal. This does reduce the unit's maneuver rate to zero. The post-deceleration period (C8.4) applies. The unit may HET or rotate as though performing a TAC under that rule.

(CJD1.41) ENERGY REQUIREMENT: Turning one hex facing costs 1 point of warp movement or 1 impulse power.
(CJD1.411) SC6 and SC7 units do not pay to turn.
(CJD1.42) NO EFFECT ON MOVEMENT: Turning does not affect a unit's movement in any way.
(CJD1.42) RATE OF TURN: A unit's maximum rate of turn depends on its turn mode. The following table shows the interval in impulses between successive turns.
Turn Mode Drone Shuttle AA A B C D E F G H
Interval 1 3
4 5 6 7 8 10 12 14 16

(CJD1.43) HIGH ENERGY TURNS: HETs are fairly normal: energy is allocated separately, the unit may break down, a HET is independent of turn mode. A HET does not affect the unit's movement vector, only its facing.
(CJD1.431) A tumbling unit will keep moving at its previous speed. The tumbling rotation stops as normal, but movement does not.
(CJD1.44) TACTICAL MANEUVERS: There are no TACs. There is nothing special about moving at speed zero; the unit may turn as normal.

(CJD1.51) WILD WEASELS: A Wild Weasel is voided by any acceleration greater than 1 or a HET. Rotation and constant speed will not void a WW.
(CJD1.52) WEB: Use the unit's speed to determine the time taken to transit a web or to resolve impacts with web.
(CJD1.53) LAUNCHED UNITS: To determine the initial movement vector of a launched unit (drone, shuttle, plasma torpedo, PF), start with the launching unit's own vector and add up to half the unit's rated speed in any direction. Unused elements of this speed can be used to accelerate (or, for SC5 units, turn) later in the turn.
(CJD1.531) To land a shuttle or PF without a tractor, the two units must share the same vector in the same hex. As a special case, the landing unit may apply acceleration in the segment of landing to achieve this.
(CJD1.54) TERRAIN: Use the unit's speed to determine the effects of asteroids, dust and so forth.
(CJD1.541) Units moving faster than 32 are treated as speed 32, but take twice the damage. For each extra 8 hexes of speed, add that much damage again.
(CJD1.55) TRACTOR: Multiply each unit's vector by its move cost and add the two to get the total vector.
(CJD1.551) The unit applying more total power controls movement. In the event of a tie, roll a die and then alternate.

(CJD1.61) WARP FRICTION: The technobabble warp friction effect causes anything moving at warp speed to slow down naturally. At the end of a turn, any unit moving at a speed more than 1 will decelerate by 1 in its largest movement element. The owning player decided which element is decreased if two are equal.
(CJD1.611) A unit moving more than 32 slows down by 2 points and takes 1 damage to the shield in the direction of deceleration. For each extra 8 hexes of speed, add 1 to each figure.

Other SFB Stuff

SFB home page (ADB Inc.)

Aaargh home

Last Revised 28/10/13