A random encounter during my campaign. Everytime you move your fleet to another hex you roll a die. 6's are pirates. 1 squadron of pirates for each squadron you have and if you have a large fleet more.
My dwarf fleet but a bit above 1k points so I had them face 2 squadrons of wargalleys and a squad of ironfists. Had a good deployment with the pirates and really had some fun with the iron fists. They ripped through 1 sub and 1 monitor during the firefight. The other wargalleys had their chances but never seemed to get the hit they needed. The subs sunk 2 ships with their torpedoes and in the end the pirate admiral was taken down during a boarding from an ironclad with full crew and a trollslayer unit at +4 vs. +3. It went a full 9 turns and went a bit better for the pirates than my games have gone so far against my dwarf fleet.
I attached the end results, you can get a feel for the lines and where the carnage was dealt

Each Ironclad had a kill and the monitors at this point in the campaign game were vets so they had some extra volleys that also sunk a ship. 5 pirate ships overall were sent to the deeps.