Sail

The Sail is an extremely important item in The Wind Waker, obtained early in the game. In, an upgraded version called the Swift Sail can be obtained.

Location and Uses
The Sail is purchased from Zunari on Windfall Island for the reasonably small price of 80 Rupees. The sail is the item which allows Link to catch prevailing winds, controlled by the Wind Waker, to sail from island to island. The sail can be set to either the X, Y or Z button on the GameCube controller (in The Wind Waker HD, the sail is permanently mapped to the B button on the Wii U GamePad). It can only be used while on-board the King of Red Lions.

Swift Sail
Exclusive to The Wind Waker HD, the Swift Sail is an upgrade to the Sail that enables the King of Red Lions to sail faster. Also, the Swift Sail automatically changes the direction of the wind to the boat's heading, thus making the King of Red Lions sail at full speed in all directions. This eliminates the need to play the Wind's Requiem when sailing. The Swift Sail is activated by pressing the A button. The upgrade is found at the Auction House on Windfall island after the completion of Dragon Roost Cavern.