Since launch day something I've wanted is AI pirate ships to attack. It just feels odd that, as pirates, there are no merchant ships to raid. You could argue that skeleton ships fill that role, but I don't believe so. Fighting skeleton ships feels more like a "good vs evil" fight, rather than being a dastardly pirate raiding merchants.
How would it work?
Similar to a roaming Skeleton Ship, these behemoth's of a ship can be found roaming around the map. Each ship has chance of carrying their respective emissary flag, along with a large amount of loot, around 50k worth. The ships would act similarly to Skeleton Ships, sailing from island to island, and occasionally stopping at outposts. These ships would be armed with 6 guns per side, and a crew of 18 AI pirates. 10 on the guns, and 8 as repairers and fighters. The ship would also have a captain like Skeleton Ships.
Forgot to add: The ship would be able to use firebombs, blunderbombs and chainshots as well, but not cursed cannonballs.
Once you initiate a fight with the ship, you have 5-10 minutes to sink it, before it raises the alarm, and you are halted from dealing with the respective trading company for 30 minutes. Attacking the ship at an outpost immediately blocks access to the trading company. Successfully sinking a Trading Company Man O' War will lower your emissary grade.
Credit to @ShootHere4EXP for this design of a Man O' War. The ships would be distinctly styled, similarly to Skeleton Ships, so that they would not get confused with regular galleons.
Each ship would be decked out with their respective Trading Company cosmetics.