A fathom is a unit of length used to measure the depth of water or the depth of objects underwater. In the international nautical mile system, one fathom is equal to exactly 1.8288 meters or approximately 6 feet. However, in the United States, the customary value for a fathom is often rounded to 6 feet.
Fathoms are commonly used in navigation, maritime activities, and underwater exploration to measure the depth of bodies of water, the draft of ships, and the depth of diving. Sailors, fishermen, and divers often use this unit to assess water depths.
A rod is a unit of length used in some systems of measurement, primarily in the United States and the United Kingdom. In the U.S. customary system, one rod is equal to 16.5 feet or 5.0292 meters. It is also equivalent to 1/4 of a chain, which is another traditional unit of length.
Rods were historically used for land measurement, particularly in surveying and real estate. In some cases, you may still come across the use of rods in property descriptions, especially in rural or agricultural areas. However, the use of the rod as a standard unit of measurement has become less common in favor of more standardized systems like the metric system or the U.S. customary system based on feet and yards.