Convert from knot to speed of light [vacuum]

Unit Definition (knot)
The Knot is common unit of velocity or speed, which is mostly referred to at sea as a measurement of boat, wind or water current velocity. One Knot is equal to one nautical mile per hour. The word comes from a former method of measuring a ship's speed, which used a knotted cord called the log line.

Unit Definition (speed of light [vacuum])
The speed of light in a vacuum is exactly equal to 299,792,458 metres per second (approximately 186,282.4 miles per second). The speed of light is denoted by the letter c, reputedly from the Latin celeritas, "speed", and also known as Einstein's constant. This exact speed is a definition, not a measurement, as the metre itself is defined in terms of the speed of light and the second.