18th Century Algerian Xebec (Barbary Corsairs)
http://www.themodelshipwright.com/high-resolution-ship-plans/sailing-vessels/french-xebec-boberach-captured-from-algeria/
Algerian xebec plan from Fredrik Henrik af Chapmanās Architectura Navalis Mercatoria (1768)
Ships like these were a real factor in control of trade. The tactics used with and against them, I hope will be represented in the open world game. Great for hit and run opportunism, especially if you have a nearby friendly coastal battery to run to. If oars are implemented, huge benefit in light winds as well.