You can purchase several valuable blueprints from the Corrupt Compagnie Officer at the Kaa Mangrove Outpost in Skull and Bones. These blueprints can significantly enhance your pirate journey, especially as Skull and Bones Items you progress through the game. Here's a list of the blueprints you can obtain there:

Blueprints Available at Kaa Mangrove Outpost
Torpedo Crate Ammunition Blueprint

Description: A crate that holds up to 60 torpedos.
Requirement: Freebooter I rank or higher.
La Forteresse I Ship Armor Blueprint

Description: Provides decent early-game ship armor to Skull and bones items for sale online strengthen your ship’s defenses.
Requirement: Freebooter I rank or higher.
Torpedo Grinder I Furniture Blueprint

Description: Increases the speed of your torpedos by 15%.
Requirement: Buccaneer I rank or higher.