All right. This is actually one of my favourite puzzles in the game
Go to the coral crushers (hair curlers
), and climb the crane. Drop the chain on the crushers, and then move it back up. The crushers will fly away.
Then, drive to the other side of the island, make sure that the conveyor belt is moving downwards (changable using the handle down there), and drop the chain on it.
Then go down to the handle, and change the direction of the conveyor belt so that it moves upwards. The chain will then be a bit messed up there.
Change the direction back downwards, and the chain will grab hold of the anchor.
Go back up to the crane, pull the chain up, and voila!