Great minds think alike, then. I got BnS and liked it, alot of it sounded familiar.
"Warships" was one of the products TSR had "all but done" for Alternity when things went belly up ... Warships, Final Church, and The Externals ... most all of them had completed manuscripts but Externals (especially) didn't have much in the way of layout design and art finished. TSR released them on their website as free PDFs for a while ... they later took them down and are offering Externals and Final Church as premium PDFs on the SVGames site (premium only in that they cost twice as much as any other PDF they have, which still isn't much for GREAT product). Warships, however, they didn't pull in the rights to and it's still available from fan sites like (I think) Tequila Starrise and Alternity.net.
Anyway, the boarding rules are very similar along with ship construction rules, etc. Not that it means much, as there's only so many broad ideas on how to do things.
I like using Warships because of its sheer SCOPE. It's a FULL SIZED book, couple hundred pages I think, with a combat system, construction rules for civilian and military hulls ranging from fighters and shuttles to Fortress Ships (name says it all). Weapons from PL 6 (small lasers and large projectile weapons with nukes and chemical explosives for missiles) to PL 9 (think Star Trek with transporters and banked energy weapons).
--fje