Where they come from
Under the coins in a chest. Lodged in something you killed. Confiscated by a gate you broke. Down a rope under a bell, or on a merchant's deck at a price. The Harbour Board adds a few to its pay. There is no shop for them in port.
Slots
A Sloop has two, A Brigantine has three, A Galleon has four. When they are full you choose what comes out, or you leave it. A fitting stays on the ship it was fitted to, moored or at sea.
All 14
Grapeshot. Cannons lose nothing at close range, and gain a third.
Boarding Hooks. Ram recoil is halved.
Storm Sails. Maneuver also fires a half broadside.
Chum Barrels. Three times a voyage, a flee cannot fail and draws no parting blow.
The Drowned Saint. Once a voyage, a blow that would sink you leaves you at 1 hull.
False Hull. If she goes down, 40% of the hold washes up in port.
Sounding Lead. Every unknown water in sight is shown to you.
Tar Pots. Bracing at close range burns what's on you for 14.
Greed's Ballast. A full hold no longer slows you. Ram +1 for every 40◆ aboard.
Siren's Wax. Acid does nothing. Spitters lose heart.
Lucky Coin. The first blow of every fight misses.
Smuggler's Charts. Home is one leg closer.
Black Flag. Tier-1 monsters flee on sight. +20% gold from everything else.
Ship's Surgeon. Patch kits heal twice as much. One more slot for them.