I just uploaded a pdf with house rules for starship design and combat, that I have been using for a while. They are mainly for star wars-like space opera, but I believe they can be used in other settings as well. They have grown out of a frustration that there have been no actual starship rules for BRP (or not much for science fiction at all - though River of Heaven seems to change that).
I have tried to keep the rules simple and quick, true to the nature of BRP. I have deviated somewhat from the recommendations for vehicles in the main rulebook, to make them more intuitive. Main focus is on choosing the functions needed for the ship, in a modular fashion, and adding a few specific stats. A simple scale concept is also added.
I appreciate all comments: overall concepts, game balance, language - anything at all.
Download link: http://basicroleplay...p-starships-20/
or try: http://ge.tt/9acymz12?c