Saturday, August 17, 2013

SciFi Saturday – Alternate Movement

Here's an alternate rule for movement in the Star Frontiers: Knight Hawks space combat game that you might consider. There's one thing about the movement rules there that always had a slightly wonky flavor to it, which I became much more sensitive to as I started playing with miniatures for the first time recently.

In SFKH, ships have to record their speed from turn-to-turn (tracking velocity/ momentum in hexes or inches). They don't have a maximum speed (space: no friction). Ships do have an ADF rating (acceleration-deceleration factor) indicating how much they can add or subtract from their speed each turn; and an MR number (movement rating) indicating how many 60° hex face pivots they can make in any turn. You have to move at least one hex between each 60° turn, but other than that, the turns can be used at any point of the move. Let's say you have a ship with MR 2 (like a Light Cruiser or a Battleship), traveling at a speed of 7. Then the following is a standard move for it to make, starting at "S":

Now, the slightly wonky thing about this is how the ship uses all of its turning capability in the first two hexes, and then has to spend the rest of the turn traveling in a straight line ahead -- and I find that the capital ships usually take exactly this kind of path, as they try to get turned at their enemies as soon as possible. It's more visible at higher speeds (in the 10's or 20's), with a higher proportion of the movement in a straight line. And it's even more pronounced for ships with MR 1 (like Heavy Cruisers and Assault Carriers) -- they become very predictable, in that after the initial clash, they're always tooling around the outside edge of the board, pivoting in the first hex of each turn.

I lived with this for 30 years, but then when I started playing on a tabletop with miniatures it started to really irritate me. "Why am I even bothering to measure these couple of 1-inch spans at the start of each move?" With figures in play, it seems overwhelmingly fiddly and you can hardly tell the difference -- you might as well let the ship use its entire MR before even starting the move, it makes so little difference. Then an alternative dawned on me: Require that the turning be equally spaced throughout the move (subject to rounding).

SFKH Alternate Movement Rule – Each ship sets its speed before movement is played out. Divide the speed by the MR and round down. This is the minimum number of hexes (inches) that the ship must move before each face-change.

Again, take the example of the MR 2 ship traveling at a speed of 7. Seven divided by 2 (rounded down), gives 3, so the ship must move at least 3 hexes before each rotation. Now the tightest turn radius that it can accomplish is the following:

So this makes me much happier. First: It has a more realistic and reasonable "feel". The ship is firing its maneuvering jets constantly throughout the movement, and the change in direction should be approximately equal throughout the turn. It's no longer front-loaded with a tight turn at the start and then an extended straight-line afterward. Second: On the tabletop, it's less fiddly and much easier to implement with ruler & compass. Instead of measuring a couple of tiny 1" spans for the starting turns (which is almost insignificant, and you're bumping into nearby models as you do it), this longer span is weighty and usually gets the ship into the open where use of the compass is easier.

Some other things upon which this will have secondary effects – Big ships with MR 1 will be restricted to making their turn at the very end of their movement (instead of at the very beginning, as was formerly the custom). Fighters and scouts using "evasive maneuvers" to dodge a torpedo must turn as quickly as possible under this rule (not once each hex). Generally in our playtest it seems like this rule makes slower speeds more desirable; big ships are usually slowing down in order maneuver better (probably not a bad thing, as traditionally huge speeds and leaving the map were problems). The rule for Speed 0 is still used as written, so a stopped ship can point at any hexside that it wishes as usual (probably even more important now). And while this rule seems to make tabletop miniatures play much smoother (where fractions of a 60° turn are permissible), it's possible that it may be trickier to implement on the hexmap (where the approach vectors are already limited by hex alignment, and traditionally I let players fiddle with their speed in the process of the move).

If you're playing the Star Frontiers: Knight Hawks game, particularly with tabletop miniatures, try it out and tell me what you think!


  1. If you're interested in trying out a completely realistic 2d vector movement system, take a look at the Vector Movement article in issue 11 of the Star Frontiersman Magazine (

    It eliminates MR altogether and bases movement solely on the ships engines as would be the case with real ships. Like your system, it makes lower speeds much more desirable for maneuverability. It's a little more complicated but not much so and should work well with miniature gaming.

    1. Thanks, good to know. I actually don't mind the standard SFKH system, even granted it's distinct unrealism -- I feel like it's a good middle ground to deal with some momentum issues, but still feel like a Star Wars-esque plane-inspired tone. There's some other indie game with full-blown vector movement I saw recently that intrigued me, but right now the title escapes me.