The Beaufort Scale of Wind Speed
(based on a Yachting Magazine item that was posted in the Vallensbæk Sejlklub
after we had attempted to sail race 1 of the '89 Worlds in 22 m/sec, i.e. 44 knots!)
.....
Beaufort 
No.
Seaman's
description
of wind
Wind
speed
in knots
Description of sea
Approximate effect
on racing dinghy
Psychological
scale
0
Calm
< 1
Sea like a mirror
    
1
Light air
1-3
Ripples, no foam crests
Crew sit on leeward side of boat or on centerline.
Boredom
2
Light breeze
4-6
Small wavelets, crests have a glassy appearance and do not break
Crew sit on windward side of boat
Mild pleasure
3
Gentle breeze
7-10
Large wavelets, crests begin to break. Perhaps scattered white caps. 
Crew ballasting on weather gunwale. Racing machines like 5-0-5, FD may   plane.
Pleasure
4
Moderate
breeze
11-16
Small waves becoming longer. Fairly frequent white caps 
Crew ballasting out hard over weather gunwale. Most dinghies will plane.
Great pleasure
5
Fresh
breeze
17-21
Moderate waves, taking a more 
 pronounced long form. Many white caps, some spray
Light dinghies have to ease sheets in heavier gusts.
Delight
6
Strong
breeze
22-27
Large waves begin to form. Extensive white caps everywhere, some spray 
Start reefing main sails
small jibs
Delight tinged
with anxiety
7
Moderate
gale
(high wind)
28-33
Sea heaps up and white foam  from breaking waves begins to be blown in   well-marked streaks along the direction
of the wind.
Anxiety tinged
with fear
8
Fresh
gale
34-40
Moderately high waves of greater length.  Edges of crests break into spindrift. The foam is blown in weIl-marked streaks along the direction of the wind.
Very difficult to sail, even under jib only
Fear tinged
with terror
9
Strong
gale
41-47
High waves. Dense streaks of foam along 
 the direction of the wind. Spray may
affect visibility. Sea begins to roll.
  
Great terror
10
Whole
gale
(heavy
gale)
48-55
Very high waves with long overhanging 
 crests. The surface of the sea takes on a
 white appearance. The rolling of the sea
 becomes heavy and shocklike. Visibility
is affected.
  
Panic
11
Storm
56-65
Exceptionally high waves. The sea is 
 completely covered with long white 
 patches of foam. Visibility is affected.
 Small. and medium-sized ships are lost
to view for long periods.
  
 I want my
Mummy
12
Hurricane
> 65
The air is filled with foam and spray. Sea completely white with driving spray. Visibility very seriously affected.
  
Yes, Mr. Jones
....
If this is too technical for you, click here
for The Coarse Sailor's Beaufort Scale!