As it asks. Through various threads, and opinions shared among them, depending on what you find on the receiving end of your macrocannons, you might not be able to just "lay claim" to an enemy human's ship (a pirate raider, maybe; this might be a reasonable way to get some light escorts for your own ship), or it might be an Orky/Eldar xeno vessel you CAN'T operate, or perhaps you're pious enough to actually see it as heresy to, whatever. Many of the ships of the void are described as ancient, massive craft, which took years to build, and may traverse the void for as many centuries. When you are done, and have disabled the raiders trying to loot you, or defeated the opposing Rogue Trader, trying to stop you from getting "their" loot, what course do you take? Do you pour shells into them until their ship explodes (probably after looting some cargo, some treasures, and "repurposing" some of their survivors to fatten your crew back up), leave it crippled, and adrift, hoping, like Dr. Evil, that things will just take care of themselves? I'm curious because many ships of most classes re still described as rare, and precious, so to hulk them, or worse seems a waste, but "bad people" rarely get better, so leaving them alive just means probably having to deal with them, again. Sending a message to the Battlefleet seems equally wasteful; they've got little time, and less manpower, to do anything about the crippled ship you left behind, and they might execute everyone for piracy, anyway.
So, at the risk of asking one more of my weird questions, post a space battle, what do you do with your opponent? Their crew? Their ship(s)?