Convert Nautical Mile (nmi) to Fathom (US Survey) (fath (US)) instantly.
About these units
Nautical Mile (nmi)
The nautical mile is a unit designed specifically for navigation. Its definition—exactly 1,852 meters—originated from the idea that one nautical mile equals one minute of arc along Earth's meridian. This geometric relationship makes nautical miles incredibly convenient for charting and navigation because latitude coordinates are given in degrees, minutes, and seconds. Aviation and maritime industries use nautical miles exclusively for distance, and knots (nautical miles per hour) for speed. Because Earth's shape and size are fundamental to navigational calculations, using nautical miles avoids the complexities that would arise if statute miles or kilometers were used instead. The unit remains globally standardized and universally understood in professional navigation.
Fathom (US Survey) (fath (US))
The US Survey Fathom is defined as 6 US Survey Feet (~1.8288 meters), identical in proportion to the traditional fathom but scaled to the US Survey Foot. Maritime surveys, early river navigation, and hydrographic measurements relied on this unit for determining depths and plotting charts. In terrestrial applications, the fathom occasionally served as a practical measure for large structures or obstacles. Although less relevant in contemporary usage, understanding the US survey fathom is crucial for interpreting historical navigation data, nautical charts, and engineering projects using older measurement systems.