Beaufort Scale     Back to Valhalla's Mooring Page  

A numerical scale for relating wind speed and sea state, devised by the British Admiral Sir Francis Beaufort in 1805. Beaufort numbers (or forces) range from force 0 (calm) to force 12 (hurricane). Sometimes (and originally) called the Beaufort scale of wind forces.

Click on the force number below to see a description of that force.  Use your browser's 'back' button to return.

FORCE (KTS)

0  (0)   1 (1-3)   2 (4-6)   3 (7-10)   4 (11-16)   5 (17-21)   6 (22-27)

7 (28-33)   8 (34-40)   9 (41-47)   10 (48-55)   11 (56-63)   12 (64+)

Note in these definitions the use of 'smack'.  A 'smack' is the type of popular (1800's) British fishing vessel whose response to the wind and waves were used as a standard in the original Beaufort scale. Thought to be a 30 foot, double-ended, open-deck sailing vessel with a gaff-rigged main.

Composite image of all force numbers