Mods, Books & Perks

Two captains in the same ship, built from the same wood, can be wildly unequal — because the hull is only the starting point. On top of it sit three separate layers of customization: modules bolted into the ship’s slots, ship knowledge (the “books”) learned permanently into that ship’s knowledge slots, and captain perks that follow you personally from one command to the next. They work in completely different ways — a module can be swapped but is destroyed when you pull it, a book is burned permanently into the ship, and perks travel with you and can be reset — and understanding which is which is the difference between a thoughtful build and a bag of random bonuses.

Modules (mods)

Modules — also called upgrades, or just “mods” — are components you fit into a ship’s upgrade slots in port to change how that specific hull performs: more speed, thicker armour, faster reload, better turning, and so on. A ship captured from an NPC arrives bare, with nothing fitted, but a ship bought at auction or from another player may come with modules already installed, which you can keep or strip out.

How many upgrade slots are available is set by the ship’s craft quality, shown by its color: gray, green, blue, purple, or gold. Higher quality unlocks more upgrade slots. This is separate from the knowledge slots used for books, which you unlock by earning experience in that individual ship. Craft quality is assigned at random when a ship is built; see Ship Crafting for how the quality roll works.

Modules come in three sizes, and the size a hull accepts depends on its rate:

• S (small) — for the little ships, ranks 6 and 7.
• M (medium) — for the mid-rates, ranks 4 and 5.
• L (large) — for the heavy hulls, ranks 1, 2 and 3.

You acquire them the way you get most gear in Naval Action — looted from wrecks, pulled from mission reward chests, or (see below) built from surplus at the Bermuda Exchange. They can’t be bought on the market or crafted. You can hover any module in your shop, warehouse, or hold to read exactly what it does before committing.

There is also a deterministic path that turns clutter into kit: the Bermuda Exchange lets you convert 10 surplus items into a guaranteed-quality module rather than gambling on wreck and chest RNG, and it’s the standard way to obtain otherwise-unique items such as fisher planking. See Port Interface for how the Exchange works.

The full catalogue of modules changes with patches and is far too long to reproduce here — you can browse the complete list on our own Shipyard: Upgrades page, and the in-port tooltips give the current effects. Which mods suit a hull depends heavily on the wood it’s built from — see Woods & Trim.

Books (ship knowledge)

Ship knowledge — the “books” — is the layer most newcomers miss. Knowledge attaches to the individual ship, not to the ship type: as you sail a particular hull and earn experience in it, that ship unlocks knowledge slots — up to five — into which you learn books. Build or buy a second ship of the same class and it starts fresh, with its own slots to unlock and fill. And unlike modules, a learned book is permanent, not slotted and swapped — it stays with that ship for as long as you own it.

You obtain a book the way you get modules — from mission chests, or looted from ships you sink or capture. Books can’t be bought from other players or crafted. With the book sitting in your hold or warehouse, you learn it into one of the ship’s knowledge slots, which consumes the book.

If you end up with duplicate or unwanted books, the Bermuda Exchange is a reliable sink: trade 5 spare books for one random encyclopedia (ship-knowledge) book. The 5-for-1 rate is fixed, but the book you get back is random, so it thins your surplus rather than letting you target a specific title. See Port Interface.

Captain perks

Perks are the only layer that is about you rather than the ship. They follow you from hull to hull — switch ships and your perks come with you — and you spend a limited budget of perk points to slot the ones that suit how you fight. Common choices reshape a whole playstyle: Combat Repairs shortens your repair cooldowns (and, as of recent patches, sinking an enemy immediately knocks several minutes off your hull and sail cooldowns); Bravery boosts repair amounts and turning; boarding-focused captains favour perks that strengthen their marines and crew. There are perks for trading, exploration, and survival too — the set rewards specialising over trying to do everything.

It helps to read the perk list as a structured menu rather than a grab-bag. As of the 2026 build the families group roughly like this — exact names and tiers get retuned patch to patch, so treat these as categories, not a fixed roster:

• Survivability — perks that keep you afloat: repair effectiveness and faster bailing of a flooding hull.
• Component strength — perks that harden a specific part of the ship: Hull, Crew, Sail, and Mast reinforcements.
• Fighting — the gunnery line: reload, accuracy, and gunpowder-related bonuses for winning the exchange of broadsides.
• Maneuverability — seamanship and turning perks that improve how the hull handles and holds a course.
• Utility and role perks — the specialists: Brawler and Sniper (opposed close- and long-range fighting styles), Merchant (trading), Mortar Officer (mortar vessels), Privateer, Fleet Control (commanding AI fleet ships), and Bravery.

Crucially, perks are not a permanent commitment the way books are. You can re-spec — clear your perks and choose again — by paying a price in doubloons, so it’s cheap to keep a combat loadout for the open sea and respec into a trading or port-battle set when the job changes. Treat perks as your flexible layer.

Putting a build together

The three layers stack, and the art is matching all of them to a single job rather than chasing every stat at once. A few principles tie it together:

• Decide the role first. A long-range line-fighter, a fast chaser, a boarding predator, and a trader want different mods, different books, and different perks. Build toward one and the choices make themselves.
• Match your investment to the risk. Perks are flexible and follow you, but modules die with the slot when you swap them, and a ship’s learned books die with the hull if you lose it. Don’t gold-plate a ship you’re about to risk in a fight you might not win.
• Books are your long game. They take the most effort to earn and can’t be recovered once learned, so concentrate them on the hulls you actually sail, and let mods and perks do the fine-tuning around them.