fathom | 1 ftm | 2 ftm | 3 ftm | 4 ftm | 5 ftm | 6 ftm | 7 ftm | 8 ftm | 9 ftm | 10 ftm | 11 ftm | 12 ftm | 13 ftm | 14 ftm | 15 ftm | 16 ftm | 17 ftm | 18 ftm | 19 ftm | 20 ftm | 21 ftm | 22 ftm | 23 ftm | 24 ftm | 25 ftm | 26 ftm | 27 ftm | 28 ftm | 29 ftm | 30 ftm | 31 ftm | 32 ftm | 33 ftm | 34 ftm | 35 ftm | 36 ftm | 37 ftm | 38 ftm | 39 ftm | 40 ftm | 41 ftm | 42 ftm | 43 ftm | 44 ftm | 45 ftm | 46 ftm | 47 ftm | 48 ftm | 49 ftm | 50 ftm | 51 ftm | 52 ftm | 53 ftm | 54 ftm | 55 ftm | 56 ftm | 57 ftm | 58 ftm | 59 ftm | 60 ftm | 61 ftm | 62 ftm | 63 ftm | 64 ftm | 65 ftm | 66 ftm | 67 ftm | 68 ftm | 69 ftm | 70 ftm | 71 ftm | 72 ftm | 73 ftm | 74 ftm | 75 ftm | 76 ftm | 77 ftm | 78 ftm | 79 ftm | 80 ftm | 81 ftm | 82 ftm | 83 ftm | 84 ftm | 85 ftm | 86 ftm | 87 ftm | 88 ftm | 89 ftm | 90 ftm | 91 ftm | 92 ftm | 93 ftm | 94 ftm | 95 ftm | 96 ftm | 97 ftm | 98 ftm | 99 ftm | 100 ftm |
span | 8 span | 16 span | 24 span | 32 span | 40 span | 48 span | 56 span | 64 span | 72 span | 80 span | 88 span | 96 span | 104 span | 112 span | 120 span | 128 span | 136 span | 144 span | 152 span | 160 span | 168 span | 176 span | 184 span | 192 span | 200 span | 208 span | 216 span | 224 span | 232 span | 240 span | 248 span | 256 span | 264 span | 272 span | 280 span | 288 span | 296 span | 304 span | 312 span | 320 span | 328 span | 336 span | 344 span | 352 span | 360 span | 368 span | 376 span | 384 span | 392 span | 400 span | 408 span | 416 span | 424 span | 432 span | 440 span | 448 span | 456 span | 464 span | 472 span | 480 span | 488 span | 496 span | 504 span | 512 span | 520 span | 528 span | 536 span | 544 span | 552 span | 560 span | 568 span | 576 span | 584 span | 592 span | 600 span | 608 span | 616 span | 624 span | 632 span | 640 span | 648 span | 656 span | 664 span | 672 span | 680 span | 688 span | 696 span | 704 span | 712 span | 720 span | 728 span | 736 span | 744 span | 752 span | 760 span | 768 span | 776 span | 784 span | 792 span | 800 span |
A fathom is a unit of length in the imperial and the U.S. customary systems equal to 6 feet (1.8288 metres), used especially for measuring the depth of water.
There are two yards (6 feet) in an imperial fathom. Originally the span of a man's outstretched arms, the size of a fathom has varied slightly depending on whether it was defined as a thousandth of an (Admiralty) nautical mile or as a multiple of the imperial yard. Formerly, the term was used for any of several units of length varying around 5–5 1⁄2 feet.
Name of unit | Symbol | Definition | Relation to SI units | Unit System |
---|---|---|---|---|
fathom | ftm | ≡ 6 ft | = 1.8288 m | Imperial/US |
fathoms | spans | fathoms | spans |
---|---|---|---|
1 | = 8 | 4 | = 32 |
1.5 | = 12 | 4.5 | = 36 |
2 | = 16 | 5 | = 40 |
2.5 | = 20 | 5.5 | = 44 |
3 | = 24 | 6 | = 48 |
A span is the distance measured by a human hand, from the tip of the thumb to the tip of the little finger. In ancient times, a span was considered to be half a cubit. Sometimes the distinction is made between the great span (thumb to little finger) and little span (index finger to little finger).
Name of unit | Symbol | Definition | Relation to SI units | Unit System |
---|---|---|---|---|
span | span | ≡ 9 in | = 0.2286 m | Imperial/US |
spans | fathoms | spans | fathoms |
---|---|---|---|
1 | = 0.125 | 4 | = 0.5 |
1.5 | = 0.1875 | 4.5 | = 0.5625 |
2 | = 0.25 | 5 | = 0.625 |
2.5 | = 0.3125 | 5.5 | = 0.6875 |
3 | = 0.375 | 6 | = 0.75 |
fathoms | spans |
---|---|
1 | = 8 |
0.125 | = 1 |
Symbol | Definition |
---|---|
≡ | exactly equal |
≈ | approximately equal to |
= | equal to |
digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |