I would like to see whalers ( whale oil was a very expensive resource in those times ). Whaling ships could catch whales only in certain areas of the map, at high sea away from land, to give some chance of catching whales and elude raiders. The whales could be fished aleatory like the bottles.
USS Essex hunted many british whalers on the Pacific before getting captured by british frigates.
This would give more content for players that like to do only trade, and would open more windows for pvp.