:: Windspeed table for Conversion of Knots, Beaufort, m/s and km/h.
Knots
Bft.
m/s
km/h
Label
Effect on sea
1
0
0 - 0,2
1
Calm
Sea like a mirror
1-3
1
0,3-1,5
1-5
Light Air
Ripples with the appearance
of scales are formed, but without foam crests
4-6
2
1,6-3,3
6-11
Light Breeze
Small wavelets, still short, but more
pronounced. Crests have a glassy appearance and do not break
7-10
3
3,4-5,4
12-19
Gentle Breeze
Large wavelets. Crests begin
to break. Foam of glassy appearance. Perhaps scattered white horses
11-15
4
5,5-7,9
20-28
Moderate Breeze
Small waves, becoming larger; fairly frequent
white horses
16-21
5
8,0-10,7
29-38
Fresh Breeze
Moderate waves, taking a
more pronounced long form; many white horses are formed. Chance of some
spray
22-27
6
10,8-13,8
39-49
strong Breeze
Large waves begin to form; the white foam
crests are more extensive everywhere. Probably some spray
28-33
7
13,9-17,1
50-61
Near Gale
Sea heaps up and white foam
from breaking waves begins to be blown in streaks along the direction of
the wind
34-40
8
17,2-20,7
62-74
Gale
Moderately high waves of greater length; edges
of crests begin to break into spindrift. The foam is blown in well-marked
streaks along the direction of the wind
41-47
9
20,8-24,4
75-88
Severe Gale
High waves. Dense streaks of
foam along the direction of the wind. Crests of waves begin to topple,
tumble and roll over. Spray may affect visibility
48-55
10
24,5-28,4
89-102
Storm
Very high waves with long over-hanging crests.
The resulting foam, in great patches, is blown in dense white streaks
along the direction of the wind. On the whole the surface of the sea
takes on a white appearance. The 'tumbling' of the sea becomes heavy and
shock-like. Visibility affected
56-63
11
28,5-32,6
103-117
Violent Storm
Exceptionally high waves (small
and medium-size ships might be for
a time lEast to view behind the waves). The sea is completely covered
with long white patches of foam lying along the direction of the wind.
Everywhere the edges of the wave crests are blown into froth. Visibility
affected
64-71
12
32,7-36,9
118-133
Hurricane
The air is filled with foam and spray. Sea
completely white with driving spray; visibility very seriously affected