Quote Originally Posted by Thaatu
Pirates are a pain in VH (because of autoresolve), but just recently in my Aedui campaign, which is H/M, I built one unit of some large ships that I can't name. They were, I believe, the best naval unit the Celts get with recruitment cost 10,000 and upkeep some 3,000 mnai. That one fleet with 50 ships (men) attacked a pirate fleet with 20 units, two of which were "Great pirate fleets", 1050 ships altogether. Heroic victory. My fleet lost about 20 ships, sinking almost 400. See, the secret in dealing with pirates is that their ships are like canoos. A real military fleet can handle any sized pirate horde.
I've never personally tried that method. I'm all about access to repair shops to save experience so my usual anti-pirate fleet (and this works quite well for my Roman empire) is 5 of the second cheapest warship you can buy. This will take a great pirate fleet with minimal losses and once you have some experience, pretty much no losses (and easy to replace if you do).

I can see smaller countries with larger borders to cover having a harder time with this though.