If you complete the "Search for Peter Blood's Ship" sidequest, you get a 6th rate frigate, specifically "SP_Postillionen". That's fine for the "Golden Age of Piracy" and "Colonial Powers" periods, but the ship type shouldn't exist in other periods. Suggestion: make the ship period dependent: "Early Explorers", "Spanish Main": caravel "Golden Age of Piracy", "Colonial Powers": 6th rate frigate as at present "Revolutions", "Napoleonic": fast merchantman The quest is based on an episode in the "Bartolomeu" storyline, and as I recall, originally had you helping Bartolomeu to find the Santiago. Of course, nobody but Bartolomeu should be sailing Bartolomeu's special caravel, so use the basic "Caravel1" for Peter Blood. The fast merchantman is a fast, agile trader with decent armament - effectively a modern equivalent to the caravel. @Bartolomeu o Portugues: as this sidequest is your work, I'm only going to implement this if you approve.