Players seeking to fully upgrade the Jackdaw in Assassin's Creed Black Flag Resynced can find a total of 12 ultimate ship plans scattered across the game world. These blueprints are essential for unlocking the most powerful enhancements for your ship.
Cannon Upgrades
The Broadside Cannons Ultimate Plan is located at coordinates (440, 145) in Charlotte, within the Blue Hole shipwreck. For the Fire Barrel Storage Ultimate Plan, collect the Petite Caverne treasure map at (862, 237) and then dig up the plan in Tulum at (40, 372). The Fire Barrel Strength Ultimate Plan requires finding the Santanillas treasure map at (191, 218) and then excavating the plan in the San Juan grotto at (455, 462). The Harpoon Strength Ultimate Plan can be found by locating the Mariguana Island treasure map at (847, 514) and digging the chest up on Andreas Island at (544, 693).
Storage and Strength Enhancements
For the Heavy Shot Storage Ultimate Plan, obtain the Cayman Sound treasure map at (298, 311) and then find the plan buried in Petite Caverne at (863, 235). The Heavy Shot Strength Ultimate Plan is acquired by picking up the Ambergris Key treasure map at (28, 159) and then locating the plan on Misteriosa at (271, 178). The Mortar Storage Ultimate Plan involves collecting the Tortuga treasure map at (851, 352) and then digging up the plan on Matanzas at (312, 617). The Mortars Ultimate Plan is found in the Antocha Wreck in Gibara at (600, 636).
Defensive and Offensive Modules
The Hull Armor Ultimate Plan, costing 30,000 reales and 400 metal, is situated within the San Ignacio shipwreck in Dry Tortuga at (348, 745). The Ram Ultimate Plan, requiring 15,000 reales, 200 metal, and 600 wood, is located in the La Conception Wreck in Chinchorra at (150, 271), inside the first chest north of the diving bell. The Round Shot Strength Ultimate Plan is discoverable at the Kabah Ruins shipwreck in the Navassa region at (738, 120), at the end of a narrow northern tunnel. Finally, the Swivel Guns Ultimate Plan, costing 15,000 reales and 400 metal, is within the Devil's Eye Caverns shipwreck in Cruz at (456, 332), in a dry chamber shortly after a tunnel loop.
These plans often require first acquiring a treasure map, which then leads to the buried chest or wreck containing the ultimate upgrade blueprint.