Bolbous bow.
A bulbous bow is a protruding bulb at the bow of a ship located just below the normal waterline. As the ship moves through the water, the bulbous bow modifies the flow of water around the hull, thereby reducing drag and increasing speed, range, and stability. Large ships (those with lengths of about 15 meters or more) with bulbous bows generally experience a 12% or greater fuel efficiency compared to similar vessels without bulbous bows. Fuel efficiency tends to increase with speed. Modeled somewhat on the ramming bows of ancient Greek triremes, the first modern bulbous bow was on the USS Delaware launched in 1910. A few other ships followed suit, but it was clearly viewed as experimental. Engineering research on the design was conducted in the 1950s, but the concept was not widely accepted until computer modeling in the 1980s proved the value of the additional work and steelweight. Now, only the smallest of commercial vessels are constructed without a bulbous bow. Original public domain image from Flickr