en.wikipedia.org/wiki/Beaufort_scale

The Beaufort scale /ˈboʊfərt/ is an empirical measure that relates wind speed to observed .... 17–21 knots, 6–9 ft ... Met Éireann issues a "Small Craft Warning" if winds of Beaufort force 6 (mean wind speed exceeding 22 knots) are expected up ...

en.wikipedia.org/wiki/Knot_(unit)

The knot is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.15078 mph. The ISO Standard symbol for the knot is kn. The same ...

www.calculateme.com/speed/knots/to-miles-per-hour/21

What is 21 kn in mph? How fast is 21 knots? This page will convert 21 knots to miles per hour.

www.metric-conversions.org/speed/knots-to-miles-per-hour.htm

Knots to Miles per hour (knots to mph) conversion calculator for Speed ... Knots to Miles per hour table - Click here for table options ... 21 knots, 24.17 mph.

www.metric-conversions.org/speed/knots-to-kilometers-per-hour.htm

Knots to Kilometers per hour (knots to kph) conversion calculator for Speed conversions with additional tables and formulas. ... 21 knots, 38.89 kph. 22 knots ...

www.grc.nasa.gov/www/k-12/WindTunnel/Activities/knots_vs_mph.html

Knots is how the speed of aircraft and boats is measured. Both miles per hour and knots is a speed which is the number of units of distance that is covered for a ...

www.disastercenter.com/convert.htm

Conversion table for knots to miles per hour, kilometers per hour, Beaufort Wind Scale, ... Speed, Descriptive term, Sea, Land. Average ... 34 km/h, 17-21 kts

www.convert-me.com/en/convert/speed/knot.html

Conversion chart for knot (Nautical, speed conversion). Instant units and measurements conversion, metric conversion and other systems. Many units supported ...