Cannon Turrets are enemies from The Legend of Zelda: The Wind Waker. They are wall mounted defenses which launch bombs at Link and his ship. They only appear in areas fortified by Ganondorf's forces, such as the Lookout Platforms and reefs of the Great Sea. After Link's initial visit, they will also appear en mass in the Forsaken Fortress, where they work in tandem with the fortress' Searchlights in order to keep intruders at bay. They are very dangerous in this area because Link can take a lot of damage. In fact, getting hit by one while on the King of Red Lions will deal 1 1/4 hearts of damage. Link can destroy a Cannon Turret with a single shot from his own cannon, or by hitting it twice with the boomerang. Cannon Turrets are also found near Warships to make it more challenging. In some areas, such as reefs, a chest will appear if Link destroys every Cannon Turret in the area. Whether Cannon Turrets are automated or controlled by an enemy within or behind them is not clear.
Interestingly, a Cannon Turret's first shot will almost always be aimed away from its target, possibly indicating that they start off with a warning shot before beginning their assault.