Question

Fathom is the unit to measure the
A. speed of the ship
B. depth of the sea
C. distance of the ship
D. speed of the cyclone

Answer 1

Hint: For this question, we will discuss how the fathom was originally defined as and what it was used for. Then we will discuss how it is defined in the imperial system and by the US customary system and how it converts to other commonly used units in the SI system and in the imperial system.

Complete step-by-step solution :
Fathom is an old unit and it is the longest of the many units derived from anatomical measurements such as foot, span, etc. It was defined as the distance from the middle fingertip of one hand to the middle fingertip of the other hand of a large man holding his arms fully extended. The word fathom comes from the Old English word faedm or faethm which meant outstretched arms. It was originally used to measure the depth of the water in the sea. It ranged from 5 to 5.5 feet. Now it is defined as exactly 6 feet or 2 yards. In SI units that is 1.8288 meters. Fathom is not accepted internationally even as a non-SI unit however has been historically the most frequently used maritime measure of the depth of the sea in the English speaking world. It was also sometimes defined as one-thousandth of a nautical mile. Hence, the correct option will be B, i.e. depth of the sea.

Note: Fathom has been defined differently over history and the exact length of one fathom varied between 5 feet to 5.5 feet. But it was always used for one purpose and that was to measure the depth of the sea. And it was the most frequently used unit to measure the depth of the sea.