Knot (unit) fluids (tidal streams, river currents and wind speeds) are also measured in knots. Thus, speed over the ground (SOG) (ground speed (GS) in aircraft) and rate of progress towards a distant point ("velocity made good", VMG) are also given in knots. Until the mid-19th century, vessel speed at sea was measured using a chip log. This consisted of a wooden panel, attached by line to a reel, and weighted on one edge to float perpendicularly to the water surface and thus present substantial resistance to the water moving around it. The chip log was cast over the stern of the
Wind assistance have been rare. Tatyana Chernova greatly outperformed the current world junior record of 6542 points with a wind-assisted score of 6768 points in June 2007 in Arles, France. Other wind-assisted series from Arles were recorded in 1987 and 2006. There is no wind speed rule for road events, but the start and finish points of a course, measured along a theoretical straight line between them, shall not be further apart than 50% of the race distance to be allowed as a record. This is due to the wind advantage that might take place for a straight course. The Athens Classic