Bulbous Bow

A bulbous bow is a rounded, bulb-shaped protrusion built into a ship's hull just below the waterline at the bow, shaped to alter the pattern of waves the hull generates so that the wave trough the bulb creates cancels out part of the crest the bow itself would otherwise produce, reducing wave resistance and, on a large ship, typically cutting fuel consumption by 12 to 15 percent compared with a conventional bow. The American naval architect David W. Taylor pioneered the underlying bulbous forefoot concept before 1900 and built it into the battleship USS Delaware, commissioned in 1910. The design proved itself commercially in the transatlantic ocean liner races of the following decades, carrying the German liners Bremen and Europa to Blue Riband speeds of 27.9 and 27.91 knots in 1929 and 1930, and letting the French liner Normandie exceed 30 knots in 1935 using roughly 30 percent less engine power than the rival Queen Mary. Dr. Takao Inui of the University of Tokyo worked out the modern theory behind the bulbous bow's drag reduction during the 1950s and 1960s, publishing a 1962 paper that measured its effect at about 5 percent, and computer modeling carried out at the University of British Columbia in the 1980s further refined how the shape is designed.