Wake

The wake is the disturbed, turbulent water a vessel leaves astern as it moves, comprising the frictional wake dragged along by the hull, the wave-pattern wake (the Kelvin V), and the propeller race. Naval architects express the wake fraction, the ratio by which water at the propeller disc moves slower than the ship, to match propeller to hull. As a hazard, wake wash from a fast or large ship can capsize small craft, surge moored vessels, and erode banks; many ports impose wash and speed limits. A wake also marks recent track for search and rescue.