Fathoms to Feet Converter
| Fathoms | Feet | What the depth is |
|---|---|---|
| 2 | 12 | the leadsman safe-water cry |
| 5 | 30 | harbor channel marker |
| 10 | 60 | coastal cruising depth |
| 15 | 90 | one shackle of chain |
| 30 | 180 | offshore bank edge |
| 100 | 600 | deep water, no bottom on hand line |
A fathom is six feet - the distance between a sailor's fingertips when the arms stretch wide, which is exactly how the unit was measured: rope pulled in arm-spans, hauled up dripping, counted in sixes. It is the unit of water depth, and the conversion never varies: fathoms x 6 = feet. Type either and the converter lands the other.
The unit carries stories in its rope: Samuel Clemens took his pen name from the leadsman's cry mark twain - two fathoms, twelve feet, safe water for a Mississippi steamboat. Anchor chains are measured in shackles of fifteen fathoms. The table runs the depths a working skipper actually calls, from twain-shallow to hundred-fathom deep water, so chart notations and feet stop being two languages.
How to use
- Type the fathoms from a chart notation or depth sounder - feet appear instantly, or run the reverse.
- Read the table for the working depths: two fathoms is the Mississippi leadsman's safe-water cry, fifteen is one shackle of anchor chain.
- Charts written in meters need one more step - convert fathoms to feet here, then feet to meters if the chart insists.
Frequently asked questions
How many feet is 1 fathom?
Exactly six feet - 1.8288 meters. The length was the average arm-span of a sailor: rope hauled in hand over hand, stretched fingertip to fingertip across the chest, counted in six-foot reaches. The modern definition fixed it at 1.8288 meters exactly, but the armspan origin is why the unit exists and why it survived - you can measure a fathom with your own body.
Why did Mark Twain choose a leadsman's cry?
Samuel Clemens piloted Mississippi steamboats before he wrote, and the leadsman swinging his sounding line called the depth aloud: by the mark, twain! meant two fathoms - twelve feet - the safe-water margin a steamboat's hull needed. Clemens kept the cry as his pen name, a working depth-sounding turned into American literature. Every fathom-to-feet conversion quietly touches the same rope.
What is a shackle of anchor chain?
Fifteen fathoms - ninety feet - one length of an anchor chain as the links were forged and joined. Anchors are dropped by shackles: the cry 'veer to three shackles' means forty-five fathoms, 270 feet of chain out. The unit survives in navies and merchant fleets because chain is stored, inspected and replaced shackle by shackle.
Do ships still measure depth in fathoms?
Older charts and older skippers do; modern hydrographic charts switched to meters in most of the world, and depth sounders display in feet or meters at a button. The fathom persists in the places tradition outvotes convenience - US nautical charts still offer fathoms, fishing grounds are still described by them, and the phrase 'deep six' (six fathoms, the burial depth) lives in the language regardless.
What is a cable length, and how does it relate?
A cable is one tenth of a nautical mile - about 120 fathoms or 600 feet - the length of a heavy ship's anchor cable in the same rope-borne tradition. Distances between ships at sea were historically called in cables. So the ladder runs: six feet to a fathom, 120 fathoms to a cable, ten cables to a nautical mile - rope arithmetic all the way down to the chart's edge.