The short answer

Buy survivability and firepower before anything cosmetic: hull armor first, then broadside cannons and mortar, then boarding-relevant crew and secondary weapons. Everything is gated by the Harbormaster at Great Inagua, so keep it levelled — an upgrade you can’t purchase yet is the real bottleneck, not the reales. A Jackdaw that survives mistakes and ends fights quickly solves more of the game than any paint job.

Resynced keeps the ship as your main power fantasy: no gear score, no levels, just a hull you make progressively more dangerous. The upgrade tree rewards a clear priority, because the ships and forts you farm for materials scale up alongside you.

Step zero: the Harbormaster gates the tree

Before any specific upgrade, understand the gate. The Harbormaster building (three levels) controls both the number and the tier of Jackdaw upgrades you can buy. If a hull or cannon upgrade is greyed out, the Harbormaster — not your wallet — is usually the reason. Level it whenever it blocks the next ship improvement you want. Its place in the wider hideout economy is covered in the Great Inagua upgrade order.

Priority one: hull and armor

Put hull armor at the front. More ship health is the single highest-value early purchase because it converts your mistakes — a bad angle, one too many enemies, a fort you underestimated — from a sinking into a survivable exchange. It also makes boarding runs and Legendary Ship attempts realistic instead of reckless. Buy hull every time a higher tier opens.

Priority two: broadside cannons and mortar

Next, offense. Broadside cannons are your bread-and-butter damage, and upgrading them shortens every fight — which in turn means you take less return fire. The mortar lets you soften forts and distant ships before they close, and stronger broadsides make boarding faster because you incapacitate targets sooner. Damage is defense here: a ship you sink quickly can’t sink you.

Priority three: secondary weapons and crew

Once the ship is tanky and hits hard, invest in the tools that shape how you fight. Secondary weapons — mortars, shrapnel, chain shot and the like — give you answers to specific situations (swarms, riggers, boarders). Crew and ram upgrades support boarding, which is the profitable way to end most encounters; pair this with the boarding versus sinking guide and the secondary fire modes guide.

Priority four: everything else

Cosmetic hull and sail skins, ship pets, and comfort options are genuine fun — buy them freely after the ship is no longer behind the local enemy tier. They don’t change a hard fight, so they belong at the end of the queue, not the middle of it. The exception is anything that unlocks a mechanical perk; treat those like the functional upgrades above.

Toward the Legendary Ships

The Jackdaw upgrade path exists to reach the naval endgame. When hull, broadsides and secondaries are near-max and you’ve recruited your Officers, you’re ready to prepare for the Legendary Ships — see the dedicated preparation checklist. Get there by always buying the upgrade that unlocks your next fight, not the one that looks the most finished.

A simple buying order

Harbormaster whenever it gates the upgrade you want.
Hull armor — survive your own mistakes.
Broadside cannons, then the mortar — end fights faster.
Secondary weapons and boarding crew/ram upgrades.
Cosmetics and pets once the ship leads the local tier.

Black Flag Resynced Jackdaw Upgrade Priority (What to Buy First)