This is called a "Bulbous Bow" It is a part of the stem and extends from the keel to just above the
ballast water line and below the load water line.

Its purpose is, has as been stated to alter the flow of water over the bow and along the forred
approximately 25% section of the hull. It cuts down drag and so increases fuel efficiency for a
given speed. This is very important on for example VLCC's which have a high fuel usage and any
fuel saving has a large effect on the overall voyage cost.