Convert Fathom (fath) to Nautical Mile (UK) (NM (UK)) instantly.
About these units
Fathom (fath)
A fathom is equal to 6 feet and is historically associated with maritime measurement. Its origins may lie in the approximate span of a fully outstretched human arms, which was convenient for measuring rope lengths by hand aboard ships. Sailors used the fathom to estimate water depth through weighted lines, giving rise to the practice of "sounding" the depths. The fathom became a cornerstone unit in nautical life because it fits the human scale while also being large enough to measure significant underwater distances. Charts, sonar readings, and older depth gauges frequently utilized fathoms, although modern equipment increasingly displays depths in meters. Still, many mariners—particularly in regions using imperial measurements—continue to think instinctively in fathoms when estimating safe anchoring or navigating shallow waters. The unit persists as an important piece of maritime history and remains in active use by traditional sailors, divers, and some fishing industries. Its survival reflects the enduring cultural heritage of nautical practice.
Nautical Mile (UK) (NM (UK))
The UK nautical mile was historically defined as 6,080 feet, slightly longer than the international nautical mile (1,852 meters). Before international standardization in 1929, British charts and maritime documents relied on this definition. It approximated one minute of latitude but used British feet rather than an exact metric conversion. Although the UK adopted the international nautical mile long ago, many older navigation charts, historical records, and maritime traditions still reference the UK version. Researchers dealing with archival naval documents must carefully distinguish between the two definitions to avoid errors in distance or speed calculations. The UK nautical mile is a reminder of the era before global standardization when each nation maintained its own measurement conventions—even for activities as universally critical as seafaring.