The Math Forum

Ask Dr. Math - Questions and Answers from our Archives
Associated Topics || Dr. Math Home || Search Dr. Math

Speed of a Knot

Date: 06/10/99 at 13:26:45
From: mo
Subject: Speed of a knot

How fast is a knot?

Date: 06/10/99 at 15:49:59
From: Doctor Rick
Subject: Re: Speed of a knot

Hi, Mo.

A knot is one nautical mile per hour. 

  1 nautical mile = 6076.115 feet
                  = 1.150779 statute miles
                  = 1.852 km (exactly)

so 1 knot = 1.15 mph = 1.852 km/h.

The length of a nautical mile is defined as the length of 1 minute 
(1/60 degree) of latitude; being not that far from a statute mile 
(5280 feet), it was given the same name. But the nautical mile is the 
natural unit of distance to use at sea, where one's position was found 
in terms of latitude and longitude by celestial navigation with the 
sextant. Therefore the knot was the natural unit for measuring speed 
at sea.

The name of the knot comes from the means of measuring a ship's speed. 
Sailors would heave a log into the water attached to a rope. The rope 
had knots in it, and a sailor would count the knots that passed 
through his hands in a certain amount of time. The book in which speed 
(measured by heaving the log) and position were recorded was called 
the ship's log, so there are at least two terms that came from this 

- Doctor Rick, The Math Forum   
Associated Topics:
Middle School Definitions
Middle School Terms/Units of Measurement

Search the Dr. Math Library:

Find items containing (put spaces between keywords):
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

Math Forum Home || Math Library || Quick Reference || Math Forum Search

Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.