Convert Fathom (fath) to Rod (US Survey) (rd (US)) 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.
Rod (US Survey) (rd (US))
The US Survey Rod equals 16.5 US Survey Feet (~5.0292 meters). Like the chain and furlong, it serves as a subdivision of larger units, maintaining consistency with historic Gunter-based measurements. Surveyors historically used rods to measure short distances, delineate boundaries, and calculate acreages. Its simple relationship to chains and furlongs made it practical for field measurements without complex arithmetic. Today, the US survey rod primarily appears in historical records, legal surveys, and when referencing pre-metric property data, providing continuity between older and modern surveying conventions.