Fathom (British/American nautical measure)

The fathom is a unit of length or distance, used mainly in the measurement of depths of water, equal to 2 yards or 6 feet. In the system based on the International yard, therefore, it is equal to exactly 1.8288 m; in the earlier (pre-1959) United States customary system and British Imperial system of length, it was slightly different but approximately the same.