Definition

An area of numerous uncharted dangers to navigation. The area charted serves as a warning to the mariner that all dangers are not charted indivi­dually and that navigation through the area may be hazardous. The term "foul" should not be applied to a soft continuum with indefinite boundaries such as mud or sand; to areas congested with marine vegetation such as kelp or grass in water; or to materials not likely to cause damage to a vessel.