Spaceship combat without Spaceships

[Stormcrow]

Let us suppose that I am running a game of GURPS without the Spaceships rules. The basic vehicle rules seem to cover the most general cases one finds in vehicle combat, even for spaceships. Provided you already have the statistics for your ships, how well does combat play out?

For instance, say we have two star freighters as given on page B465. If you play out a combat turn-by-turn, approximately how long will it take to finish the combat? How many choices will the players have to make? Is it any good?

I have never run a vehicle-based combat in GURPS, especially not one centered around spaceships, so what I am looking for is a general impression that ignores the Spaceships rules, as if they didn't exist—no comparisons to those rules. (I would try it out myself, but I am at work right now, and they might frown on that sort of diversion. I can get away with Web forums.)