Actually knots are derived from SI, being based on nautical miles (which are SI)...

		imglorp on Oct 5, 2016 \| parent \| context \| favorite \| on: The eye of hurricane Matthew passes directly over ... Actually knots are derived from SI, being based on nautical miles (which are SI), which are 1/60th of a degree of latitude. So they're not completely useless or arbitrary like other imperial units.