Smart mines

One way to represent this:

The entire board is a minefield. Targets get attacked (beam dice?) by X number
of mines per turn, where X gets smaller the faster the ship is moving.

Perhaps (if cinematic): Speed 30 = no mines
24-29 = 1 beam dice
19-24 = 2 beam dice
etc.
1-6 =  5 beam dice
0 (sitting duck) = 6 beam dice

This is a no bookkeeping way to "keep the players fleet moving". If they zip
around and move quickly (or get in the board and off the board), they take
very little minefield damage (represents mines not having time to concentrate
where they are). If they lumber about or go slowly, the mines get time to
concentrate.

This is an abstraction, but that's a lot of what FT is about - try
for an effect rather than a specific detailed description of mechanism.

Note this doesn't tie you to any particular interpretation of the mines
attack. You could use other die mechanics other than beam dice.

Tomb