Drop the treasure chests in the icy water of the North Pole so that the pirates can pick them up. You can move the chests by cutting chains for instance. You could also roll other objects against them, or even blow up bombs to push the chests in the water. Icebergs can be removed by clicking on them.
Click on a chain to cut it or on an iceberg to make it disappear. When you would like to restart the level you press space.