Black Flag Resynced Ultimate Plan Locations — All 12 Coordinates and How to Get Them

To unlock the final tier of Jackdaw upgrades in Black Flag Resynced, you need all 12 Ultimate Ship Plans. Six are found in underwater shipwrecks (requires the Diving Bell, unlocked in Sequence 6), and six come from buried treasure (find the treasure map first, then sail to the dig location). Plan your upgrade costs while you collect — the calculator shows exactly what each plan unlocks and what it costs to install.

Important: What You Need First

Diving Bell: Unlocked automatically in Sequence 6, Mission 1 ("Diving for Medicines"). Without it, you cannot access any shipwreck plans.
Harbourmaster Level 3: Even after finding all 12 plans, you must fully upgrade the Harbourmaster at Great Inagua (8,000 Reales total) before purchasing Ultimate-tier upgrades.
Nothing is missable. All plans can be collected after the story ends.

Shipwreck Dive Plans (6 Plans — Requires Diving Bell)

1. Hull Armor Elite Plan

Unlocks: Armored Hull V (+1,800 armor)
Location: San Ignacio Wreck, Dry Tortuga
Coordinates: [348, 744]
Danger: Sharks patrol the wreck interior. Use kelp for cover. Equip the Diamond Trinket for extra oxygen.

2. Broadside Cannons Number Plan

Unlocks: Broadside Cannons VII
Location: The Blue Hole, Charlotte
Coordinates: [440, 145]
Note: Deep dive — you'll need full oxygen capacity. The chest is in the eastern chamber.

3. Round Shot Strength Plan

Unlocks: Round & Heated Shot V (+50% damage)
Location: Kabah Ruins, Navassa
Coordinates: [738, 120]
Danger: Multiple sharks. The plan is in a chest behind a breakable wall — use a heavy attack underwater.

4. Mortar Strength Plan

Unlocks: Mortar IV (+100% damage)
Location: Antocha Wreck, Gibara
Coordinates: [600, 636]
Danger: Heavy shark activity. Consider clearing sharks with the harpoon before diving.

5. Ram Elite Plan

Unlocks: Ram IV (+2,000 ram damage)
Location: La Concepción Wreck, Chinchorro
Coordinates: [150, 272]
Note: The wreck is split into two sections. The plan is in the deeper southern section.

6. Swivel Guns Elite Plan

Unlocks: Swivel Guns IV (max damage)
Location: Devil's Eye Caverns, Cruz
Coordinates: [456, 332]
Note: Narrow underwater tunnels. Follow the light beams — they mark the path to the chest.

Treasure Map Plans (6 Plans — Available Anytime)

For each of these: find the treasure map at the first location, then sail to the dig site. The map shows a sketch of the dig location — match landmarks, not coordinates.

7. Heavy Shot Strength Plan

Map location: Ambergris Key [28, 160]
Dig location: Misteriosa [271, 178]
Unlocks: Heavy Shot III (+67% damage)

8. Fire Barrel Strength Plan

Map location: Santanillas [191, 218]
Dig location: San Juan Cave [455, 462]
Note: The dig site requires swimming through an underwater tunnel.

9. Heavy Shot Storage Plan

Map location: Cayman Sound [298, 311]
Dig location: Petite Caverne [863, 235]

10. Mortar Storage Plan

Map location: Tortuga [851, 352]
Dig location: Matanzas [312, 617]

11. Fire Barrel Storage Plan

Map location: Petite Caverne [862, 237]
Dig location: Tulum [40, 372]

12. Harpoon Strength Plan

Map location: Mariguana Island [847, 514]
Dig location: Andreas Island [544, 693]
Note: The dig spot is on the north shore, behind a rock formation.

Efficient Collection Order

Before Sequence 6: Collect all 6 treasure map plans. They're available as early as Sequence 2 and don't require the Diving Bell.
Sequence 6: Immediately do the "Diving for Medicines" mission to unlock the Diving Bell.
After Sequence 6: Collect all 6 shipwreck plans. Start with the easiest wrecks (San Ignacio, Antocha) and save Kabah Ruins for last (most sharks).
Don't forget: Upgrade the Harbourmaster to level 3 before trying to purchase Ultimate-tier upgrades.