The galleon. I'm thinking the more versatile, generic kind of galleon used by the Spanish, English and Portuguese until right before the conflict of the Spanish Armada (by then Drake had the racebuilt galleon at his command, and that one is more military in nature).
I think the galleon would be a good first product, since it can serve a multitude of purposes, from merchant and passenger vessels, to low-end military vessels.
Remember what I said, I would heap praises everlasting upon those who release such a product.