What is a Knot? Nautical Measurements Explained

If you watch movies about the Navy, you hear speed given in "knots." But what is a knot?

Speed on Water

One knot equals one nautical mile per hour. A nautical mile is slightly longer than a standard (statute) mile: 1.15 miles.

Why Not Use Miles?

A nautical mile is based on the Earth's circumference. It is equal to one minute of latitude. This makes navigation incredibly easy for sailors using charts and maps. If you travel 60 nautical miles north, you have traveled exactly one degree of latitude.

The Name "Knot"

Sailors used to measure speed by throwing a wooden log attached to a rope into the water. The rope had knots tied at specific intervals. As the ship moved, they counted how many knots unspooled over a set time.