What Is Fathom?
A fathom is a unit for measuring depth, mostly in water. It tells us how deep the sea, a river, or a lake is. One fathom is the same as six feet. Sailors, divers, and fishers often use fathoms when they talk about how deep the water is.
Definition
A fathom is a length unit used for depth, mainly in the sea.
By international agreement:
- 1 fathom equals 6 feet
- 1 fathom equals 2 yards
- 1 fathom equals about 1.8288 meters
So if you know the number of fathoms, you can work out how many feet or meters deep the water is.
History / Origin
The word fathom comes from an old English word that meant outstretched arms. Long ago, people measured a fathom by stretching their arms wide and measuring from fingertip to fingertip. This was close to the height of an adult person.
Because it was easy to use the body as a measuring tool, sailors started using the fathom to measure ropes and anchor lines. Over time, the fathom became the common way to measure water depth for ships, especially in British and American sailing.
Later, the fathom was fixed to a clear value, exactly six feet, so that everyone would use the same length.
Symbol & Abbreviation
The full word is written as fathom.
Common short forms are:
- ftm for fathom
- Sometimes just the word fathom is written after the number
On some old sea charts, you may also see a single quote mark next to a number to show fathoms, but modern charts more often use meters.
Current Use Around the World
Today, the fathom is not a main unit in science, but it is still used in some special areas.
- Shipping and boating Some sailors and fishers still talk about water depth in fathoms, especially in English speaking countries.
- Diving Some scuba divers and free divers use fathoms when talking about dive depths.
- Old sea charts Many older nautical charts show depths in fathoms, so people who use these charts must understand the unit.
- Everyday language In English, the word fathom can also mean to understand something deeply, like to fathom an idea.
However, many countries and modern sea charts now use meters instead of fathoms, because meters are part of the metric system.
Example Conversions
Here are some easy examples of how to change between fathoms, feet, yards, and meters.
Basic facts
- 1 fathom equals 6 feet
- 1 fathom equals 2 yards
- 1 fathom equals about 1.8288 meters
Fathoms to feet
- 1 fathom equals 6 feet
- 2 fathoms equals 12 feet
- 5 fathoms equals 30 feet
- 10 fathoms equals 60 feet
- 20 fathoms equals 120 feet
Fathoms to meters
- 1 fathom is about 1.83 meters
- 5 fathoms is about 9.14 meters
- 10 fathoms is about 18.29 meters
- 50 fathoms is about 91.44 meters
Real world style examples
- If a sign says the water is 3 fathoms deep, that is 18 feet or about 5.49 meters.
- If a diver goes down 6 fathoms, that is 36 feet or about 10.97 meters.
- If a ship anchors in 15 fathoms of water, that is 90 feet or about 27.43 meters.
Related Units
These units often appear together with the fathom in sea and distance measurements.
- Foot A unit of length. 1 fathom equals 6 feet.
- Yard Another length unit. 1 fathom equals 2 yards.
- Meter The main metric unit of length. 1 fathom is about 1.8288 meters.
- Nautical mile A unit used at sea for long distances. 1 nautical mile equals 1852 meters. Fathoms are for depth, nautical miles are for distance over the water surface.
- Cable A sea unit used for length of anchor chains and short sea distances. In some systems, 1 cable is about 100 fathoms.
- League An old long distance unit sometimes used at sea. League values varied in history and are not used much today.
FAQs
How many feet are in one fathom
One fathom is exactly six feet. So to change fathoms to feet, you multiply the number of fathoms by six.
Why do sailors use fathoms
Sailors use fathoms because the unit came from the span of human arms and was easy to measure with ropes. It became a tradition in sea travel and is still used in some sea activities today.
Is the fathom still used today
Yes, but not as much as in the past. It is still used by some sailors, divers, and fishers, and it appears on older sea charts. Many modern charts and rules use meters instead.
How deep is 100 fathoms
To find the depth in feet, multiply by six. So 100 fathoms equals 600 feet. In meters, 100 fathoms is about 182.88 meters.
How do I convert fathoms to meters quickly
To get a quick answer, you can remember that 1 fathom is almost 1.8 meters. So you can multiply the number of fathoms by about 1.8 to get meters as a rough idea.
Is a fathom used only for water depth
Mostly yes, it is mainly used to measure water depth or length of ropes and chains on ships. In everyday life on land, people rarely use fathoms.