The Legend of Zelda The Wind Waker 100% #32 Islet Of Steel (No Commentary)

These waters are swarming with gunboats, so be sure to equip your cannon and be ready to defend yourself. Take them out. They leave behind sunken chests worth 50 Rupees each.
Sail to the small iron fortress and blow up the ship guarding its entrance. Sail inside (push forward on the analog stick to move while there's no wind) and climb up the stairway.
Stand on the wind symbol and play the Wind's Requiem to make a treasure chest appear. Inside, you will find Triforce Chart 1.
Look for a pirate platform in the southwest/center of the square. Fight two Wizzrobes and two Bokoblins to get a treasure chest with a Skull Necklace.