Knot = Nautical Mile, which is a little over a mile, or 1.852 Kilometers. So, 6 knots/hour is 6 nautical miles, or 7/6.9 MPH.
Yeah, knew that stuff well in scaling down the knots for 10 minute reaches to determine speed on some planing cat designs I was trying out (foam filled sintra sponsons - next time I might try thin cedar, should look a lot prettier, too)). Hit 39/40 knots/hour on one before the dart boards snapped, ending the time trial (without the dart boards, the wind pushed it sideways, off to angle, killing the heading forward speed, losing 'weather helm', etc - ugly). I'll know to use hardwood dart boards next time
fyi: knots have nothing to do with knots. A knot as has been determined is one nautical mile an hour but that nautical mile is one minute of arc of latitude.
Maybe knots were done to try to determine a speed but never accurately enough to determine location except by dead reckoning but that doesn't get you across the Atlantic.
fyi: knots have nothing to do with knots. A knot as has been determined is one nautical mile an hour but that nautical mile is one minute of arc of latitude.
Maybe knots were done to try to determine a speed but never accurately enough to determine location except by dead reckoning but that doesn't get you across the Atlantic.
.02% is pretty close.
From wiki;
Until the mid-19th century vessel speed at sea was measured using a chip log. This consisted of a wooden panel, weighted on one edge to float upright, and thus present substantial resistance to moving with respect to the water around it, attached by line to a reel. The chip log was "cast" over the stern of the moving vessel and the line allowed to pay out. Knots placed at a distance of 47 feet 3 inches (14.4018 m) passed through a sailor's fingers, while another sailor used a 30 second sandglass (28 second sandglass is the current accepted timing) to time the operation.[8] The knot count would be reported and used in the sailing master's dead reckoning and navigation. This method gives a value for the knot of 20.25 in/s, or 1.85166 km/h. The difference from the modern definition is less than 0.02%.
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