Assassin’s Creed 4 Black Flag Resynced Swivel Guns Ultimate Plan Location

Swivel Guns Ultimate Plan in Assassin’s Creed IV Black Flag Resynced is needed to buy the final Swivel Guns ship upgrade at the harbourmaster.

Swivel Guns Ultimate Upgrade Plan Location

Swivel Guns Ultimate Plan is looted from an underwater chest in Devil’s Eye Caverns Shipwreck (456, 332).

For all other Plans refer to All Ultimate Upgrade Plan Locations and for everything else also check the Collectible Guide.