Bow wave

File:Bow wave 1.jpg

Bow wave of a canal barge

A bow wave is the wave that forms at the bow of a ship when it moves through the water. As the bow wave spreads out, it defines the outer limits of a ship's wake. A large bow wave slows the ship down, poses a risk to smaller boats, and in a harbor can cause damage to shore facilities and moored ships. Therefore, ship hulls are generally designed to produce as small a bow wave as practical.

Description

File:USS Connecticut (BB 8) speed trials.jpg

Bow wave of the USS Connecticut, on her speed trials in 1906 or 1907.

The size of the bow wave is a function of the speed of the ship, its draft, surface waves, water depth, and the shape of the bow. A ship with a large draft and a blunt bow will produce a large wave, while ships that plane over the surface of the water will create smaller bow waves. Bow wave patterns are studied in the field of computational fluid dynamics.

The bow wave carries energy away from the ship at the expense of its kinetic energy—it slows the ship down. A major goal of naval architecture is therefore to reduce the size of the bow wave and improve the ship's fuel economy. Modern ships are commonly fitted with a bulbous bow to achieve this.

A bow wave forms at the head of a swimmer when he moves through the water. The trough of this wave lies near the mouth of the swimmer and helps the swimmer inhale air to breathe just by turning his head. The water of the bow wave, on falling from the height which it attains, bounds and rebounds upon the water-bed.

See also

• Shock wave

References

de:Bugwelle