Windy Sail

The Windy Sail is both a Ship Customization item and a "Ship-speed booster item" that is only obtainable by looting a Pirate Shipwright.

The Windy Sail is meant to be used only for the Sailing Raft and the Small Sailboat. It is a placeable object that only makes a visual difference once the sail on that particular boat is up. Like any other Ship Customization item, it can be recollected by holding "F" (default key).

Since the 2.0 update, this item has been removed from the game. If you had any windy sail in your inventory and in your chests, they will be replaced with Toy Windy Sailboat.

Source

 * Pirate Shipwright
 * Ship Customization