Enjoy an unwieldy giant rulebook.

Do you have rules for C-fractional merging battles?

Even 'Take the sheets for both ships, and put them in a shredder' would be acceptable.

Are you talking like two ships trying to fight at C-fractional speeds or ramming into each other at C-Fractional speed?

Cause in the latter there would be merging and then some ship sheets into the metaphorical shredder.

two ships fighting at C-fractional speed, with railguns or autoguns or what-have-you.

Ah, most ship's don't fight that fast since they have to stay dangerously close to get proper locks due to tracking disruptor. Mind you, if you DO manage to fire a railgun while already going at C-Fractional

Ship shredding should ensue.