*This guide contains minor spoilers for Assassin’s Creed Black Flag Resynced
For the most part, in Assassin’s Creed: Black Flag Resynced, Edward Kenway’s ship, the Jackdaw, can be leveled with a steady stream of materials and finances. This changes, however, when you reach the final stage of each metric. Here, the game throws an additional requirement, a blueprint for the Ultimate plan that allows you to achieve the final level, along with materials and finances.
For the most part, even without these, the Jackdaw is a competitive ship in most of the Caribbean, but there are a few reasons you want to go through this process. The first of which are the Legendary ships that sail each corner of the map. Even with these upgrades, you need a strong command of the brace ability to survive these encounters, but the first step is leveling everything. The second is if you haven’t finished Forts, these will surely help. Forts are completeable even before, but they largly bombard the player from multiple points, so this is added damage and protection is benefitial. Finally, fully upgrading the ship nets you the Ship This trophy/achievement, so if you are a completionist, it is worth it.

Shipwreck Diving Spots
The first thing you need to know is that it will set you on your way to fully upgrading the Jackdaw, and that shipwreck diving spots typically have one of the Ultimate Plans contained within. You gain access to diving spots in Sequence 6 and involve Edward in diving down to a shipwreck with treasure chests and secrets to find. There are seven spots in total on the map, one for each of the mythological seven seas, if you will, and diving all of them gets you the Seven Deadly Seas trophy/achievement, so you can clear two trophies in the process.
Ultimate Plans are contained in secret chests, not treasure chests. You can tell the difference because the latter ones are smaller and partially open, whereas the secret chests are closed and more boxy. You can check the image above as a reference point. Here is where you can find the underwater chests:
- Hull Armor – San Ignacio Wreck, (348,745)
- Round Shot Strength – Kabah Ruins, (738,120)
- Broadside Cannon Numbers – The Blue Hole, (440,145)
- Swivel Guns Strength – Devil’s Eye Caverns, (456,332)
- Mortar Strength – Antocha Wreck, (600,636)
- Ram – La Concepción Wreck, (150,271)
As you can see, only six of the seven contain an ultimate plan. These are not listed in any particular order, but I would recommend getting the Hull Armor first, above everything else.

Buried Treasure
The remaining plans can be found by completing the treasure maps you have probably started collecting up until this point. These are pretty easy to follow, giving a location and fairly exact coordinates to locate them. They also offer pretty representative pictures of the area you will locate them in as well. The only thing is you might have to run around in circles for a tiny bit before finding a ‘dig here’ prompt. Here is a list of both the Map locations and where their buried treasure is:
- Heavy Shot Strength – Misteriosa Map: Map located in Ambergris Key (28, 159), treasure located in Misteriosa at (271,178)
- Heavy Shot Storage – Petite Caverne treasure map: Map located in Cayman Sound (301,309), treasure located in the Petite Caverne at (863,235)
- Fire Barrle Strength – San Juan map: Map located in Santanillas (187,219), treasure located in San Juan Smugglers Cove at (455,462)
- Fire Barrel Storage -Tulum map: Map located in Petite Caverne (864,237), treasure located in Tulum at (40,372)
- Mortar Storage – Jiguey map: Map located in Tortuga (848,350), treasure located in Jiguey at (534,510)
- Harpoon Strength – Andreas Island map: Map located on Mariguana Island (848,514), treasure located on Andreas Island at (544,693)
The final upgrade for the harpoon is a must-get for hunting the Great White Shark and is necessary to upgrade Edward Kenway’s persona kit fully. Players can also earn the Perfect Predator trophy/achievement for landing a perfect harpoon throw on a great white shark. Now all that is left is to shell out the money and materials to see these upgrades to fruition.

If you are looking for more help with Assassin’s Creed: Black Flag Resynced, like locating the lowest point in the map to earn the Davy Jones’ Locker trophy/achievement, you can click the link to check out that guide. You can also check out our review of the game here.
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