fathom (US survey) [fath] Unit Converter

Definition of fathom (US survey) [fath] unit

A fathom (US survey) is a nautical unit of length equal to six US survey feet, or approximately 1.8288 meters. It traditionally measures water depth, rope length, and other distances in maritime contexts.

History of fathom (US survey) [fath] unit

The fathom developed from practical human measurements, probably relating to the span of a man’s outstretched arms. The word comes through Middle English from Old English fæthm, meaning an embracing or extended reach. Seafarers adopted it as a convenient way to sound depths and handle lines. In the United States, the customary fathom was standardized as six feet; under surveying conventions, a US survey fathom equals six US survey feet, slightly longer than six international feet. Although metric units dominate modern measurement, the term remains embedded in nautical tradition.

Applications of fathom (US survey) [fath] unit

Today, a US survey fathom is used mainly in nautical and historical contexts. Mariners may describe water depth, especially on older charts or in traditional seamanship, while fishing, diving, and marine construction can involve fathom-based measurements. For example, a chart may record a depth as 10 fathoms, meaning about 18.288 meters, although meters are now preferred internationally.

Complete list of fathom (US survey) [fath] unit conversion