Looking for a space shipbuilder/ship combat system to tack on to D&D 5e game

[knag]

*coughSPELLJAMMERcough*

Just noticed this and that's actually not bad idea. SJ does very little to take advantage of the 3D nature of space combat, so it's really just naval combat re-skinned. It has quite a variety of ships and weapons including firearms, and a very workable combat system. Still no real system of shipbuilding, but for combat that's probably the best D&D ship-to-ship system out there.