Bulbous bow

A bulbous bow is a faired forward protrusion below the waterline that generates its own wave train roughly out of phase with the hull’s bow wave, partly canceling it and cutting wave-making resistance near the design speed. The gain is speed-specific: a bulb tuned for full-draft service speed can add resistance in ballast or off-design. It is sized by length, area, and vertical position relative to the forward perpendicular, and it also damps pitching slightly.