For any admirals looking to spare their ships damage or repair costs during the campaign, here's something funny I've come across with the AI. Factions like Chaos, IN, Orks tend to follow their second flagship if the first is destroyed. You can use any stealth ship to bait the flagship towards your other heavier ships in gas clouds or asteroid fields so long as your LC or escort remains closer to the enemy than the ships in hiding.
This tactic works best for large enemy fleets (3v1) after its escorts are gone. This comes in handy when doing a hard playthru. Here's one of the funnier instances of it in action: