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iSealife Nautical References!
"Non-sailing readers may be wondering how strong a Force 7 wind is. Back in the early 1800's before anemometers were invented, a certain Captain Beaufort of the Royal Navy decided to settle the perennial arguments, particularly as between sailors and lands-people, as to just how windy it was. He came up with a qualitative scale of wind strengths from 0 to 12. Its still in use in the English speaking world, and known as the Beaufort Wind Scale. For example, in the well known UK Shipping Forecasts on the BBC, Beaufort's language has a lovely prosaic ring. At sea, a Force 3 wind produces "Large wavelets, crests begin to break, scattered whitecaps" and on land "Leaves and small twigs in constant motion, light flags extended". Later technology allowed wind speed in knots to be applied to Captain Beaufort's scale. For example a Force 3 is between 7 to 10 knots, a Force 4 between 11 and 16 knots, and a Force 8 is 34 to 40. A rough conversion formula is the Beaufort Force # minus 1, multiplied by 5, equals wind strength in knots. By the way, a knot is a nautical mile per hour. A nautical mile is equal to 1.146 land miles (mph)."Tony Gooch"
| Force | Wind | Sea |
| 0 | Less than 1 Kt. | 0 Mirror |
| 1 | 1 - 3 Kts. | Less Than 1 Ft. |
| 2 | 4 - 6 Kts. | .5 - 1 Ft. |
| 3 | 7 - 10 Kts. | 2 - 3 Ft. |
| 4 | 11 - 16 Kts. | 3 - 5 Ft. |
| 5 | 17 - 21 Kts. | 6 - 8 Ft. |
| 6 | 22 - 27 Kts. | 9 - 13 Ft. |
| 7 | 28 - 33 Kts. | 13 - 19 Ft. |
| 8 | 34 - 40 Kts. | 18 - 25 Ft. |
| 9 | 41 - 47 Kts. | 23 - 32 Ft. |
| 10 | 48 - 55 Kts. | 29 - 41 Ft. |
| 11 | 56 - 63 Kts. | 37 - 52 Ft. |
Force 0: Wind Speed less than 1 knot. Sea like a mirror.
Force 1: Wind Speed 1 - 3 Knots. Sea wave height .1m (.25ft.); Ripples with appearance of scales, no foam crests.
Force 2: Wind Speed 4 - 6 Knots. Sea wave height .2 - .3m (.5 - 1ft.); Small wavelets, crests of glassy appearance, not breaking.
Force 3: Wind Speed 7 - 10 Knots. Sea wave height .6 - 1m (2 - 3ft.); Large wavelets, crests begin to break, scattered whitecaps.
Force 4: Wind Speed 11 - 16 Knots. Sea wave height 1 - 1.5m (3.5 - 5ft.); Small waves becoming longer, numerous whitecaps.
Force 5: Wind Speed 17 - 22 Knots. Sea wave height 2 - 2.5m (6 - 8ft.); Moderate waves, taking longer form, many whitecaps, some spray.
Force 6: Wind Speed 22 - 27 Knots. Sea wave height 3 - 4m (9.5 - 13ft.); Larger waves forming, whitecaps everywhere, more spray.
Force 7: Wind Speed 28 - 33 Knots. Sea wave height 4 - 5.5m (13.5 - 19ft.); Sea heaps up, white foam from breaking waves begins to be blown in streaks along direction of wind.
Force 8: Wind Speed 34 - 40 Knots. Sea wave height 5.5 - 7.5m (18 - 25ft.) Moderate high waves of greater length, edges of crests begin to break into spindrift, foam is blown in well marked streaks.
Force 9: Wind Speed 41 - 47 Knots. Sea wave height 7 - 10m (23 - 32ft.); High waves, sea begins to roll, dense streaks of foam along wind direction, spray may reduce visibility.
Force 10: Wind Speed 48 - 55 Knots. Sea wave height 9 - 12.5m (29 -41ft.) Very high waves with overhanging crests, sea takes white appearance as foam is blown in very dense streaks, rolling is heavy and shocklike, visibility is reduced.
Force 11: Wind Speed 56 - 64 Knots. Sea wave height 11.5 - 16m (37 - 52ft.); Exceptionally high waves, sea covered with white foam patches, visibility still more reduced.