Fathom
From Free net encyclopedia
- For other uses, see Fathom (disambiguation).
A fathom is an obsolete non-SI unit of length formerly used in the United Kingdom and her former colonies. It was often used as a measure of depth using a lead-weighted sounding line. By extension, "to fathom", has come to mean "to measure", "to get to the bottom of" or "to understand" something.
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Definition
Origin
The name derives from the Old English word fæthm meaning 'outstretched arms' which was the original definition of the unit's measure. In Middle English it was fathme.
Explanation
The length is equivalent to 2 yards. The fathom was first used for land measurement but is now restricted to nautical uses, especially the measurement of the depth of water or the length of nautical rope or cable. Civilian maps in English-speaking countries used to have depths commonly marked in fathoms, but this has changed to metres generally, even in US maps. Nautical charts have changed on a separate schedule.
Sounding
It is easy to measure a length of line or rope as a rough number of fathoms by repeatedly stretching the rope between the two outstretched arms. Water depths have traditionally been measured this way by a "leadsman" using a sounding line. The word fathom can be used as a verb to describe this process.
On the Mississippi river in the 1850s, the leadsmen also used old-fashioned words for some of the numbers; for example instead of "two" they would say "twain". Thus when there was only two fathoms left under the boat they would call "by the mark twain!". The American writer Samuel Clemens, a former river pilot, took his pen name, "Mark Twain", from this cry.
Analogous units
The fathom is a generic unit and an analogous measure can be found in many cultures. Some are listed below.
| Czech | sáh |
| Danish | favn |
| Dutch | vadem |
| Estonian | süld |
| Finnish | syli |
| French | toize (circa 1150), brasse (1409) |
| German | klafter |
| Hungarian | öl |
| Italian | braccio |
| Japanese | hiro(尋) |
| Norwegian | favn |
| Polish | sążeń |
| Portuguese | braça |
| Russian | морская сажень |
| Sanskrit | vyama |
| Serbian | хват/hvat |
| Slovak | siaha |
| Spanish | braza |
| Swedish | famn |
References
- An explanation of the fathom marks used at sea (retrieved Sept 2005).de:Fathom
et:Süld eo:klafto fr:Brasse ja:ファゾム nl:Vadem no:Favn pl:Sążeń ru:Сажень sl:seženj sv:Famn zh:噚