KNOTS

One (international) knot is exactly equal to 1.852 Kilometres per hour (Km•h−1), and is approximately equal to the following:

One nautical mile converts to:

101.268591 feet/minute

1.687810 feet/second

0.5144444 meters per second (m•s−1)

1.150779 mile (statute)/hour (mph)

0.99936 Admiralty knot

0.998383 geographical mile

1.852 km (exact)

1.150779 mile (statute) [1]

2025.372 yard

6076.1155 feet

1 meridian arc minute at sea-level surface distance

There is no relationship between speed (knots) on water & speed (mph/kph) on land. Speed/Distance on land is always fixed as land is immovable, whereas water has current flowing with or against the vessel. The speed relationship between the vessel and the surface it travels upon changes constantly.

Historically the nautical mile was defined as a minute of arc along a meridian of the Earth. It can therefore be used for approximate measures on a meridian as change of latitude on a nautical chart. By the definition of geodetic latitude, length of the minute of arc depends on the radius of curvature. This length equals to approximately 1849.12 meters at the poles and 1855.34 meters at the Equator.