The skin with its layer of about 12 inches of blubber is peeled off with a hook and cable drawn back by a steam winch. The sperm oil is the whale's most valuable product. This is obtained from the foot-thick layer of fat just below the outer hide. After longitudinal slices are made, the nose end of the hide with its layer of fat is hooked and drawn back with a steel cable and steam winch. Attendants stand by to cut the flap free from the flesh below.