| |
 |
|
Scale |
|
|
|
|
|
|
|
|
|
|
|
| |
|
Sailor’s description |
Speed
m/sec |
Wind knots |
|
Effects of wind
on sea |
|
|
Probable wave
height
(metres) |
| |
|
|
|
|
|
|
|
|
media |
max |
| 0 |
|
Calm (up to): |
0
- 0.2 |
fino
a 1 |
|
Sea
is like a mirror and smoke rises vertically. |
|
|
- |
- |
| 1 |
|
Light
air |
0.3
- 1.5 |
1
- 3 |
|
Ripples
with the appearance of scales are formed,
but without foam crests. |
|
|
0.1 |
0.1 |
| 2 |
|
Light
breeze |
1.6
- 3.3 |
4
- 6 |
|
Small
wavelets, still short, but more pronounced.
Crests have a glassy appearance and do not
break. |
|
|
0.2 |
0.3 |
| 3 |
|
Gentle
breeze |
3.4
- 534 |
7
- 10 |
|
Large
wavelets. Crests begin to break. Foam of glassy
appearance. Perhaps scattered white horses. |
|
|
0.6 |
1.0 |
| 4 |
|
Moderate
breeze |
5.5
- 7.9 |
11
- 16 |
|
Small
waves, becoming larger; fairly frequent white
horses. |
|
|
1.0 |
1.5 |
| 5 |
|
Fresh
breeze |
8.0
- 10.7 |
17
- 21 |
|
Moderate
waves, taking a more pronounced long form.
Many white horses are formed. Chance of some
spray. |
|
|
2.0 |
2.5 |
| 6 |
|
Strong
breeze |
10.8
- 13.8 |
22
- 27 |
|
Large
waves (breakers) begin to form; the white
foam crests are more extensive everywhere.
Probably some spray. |
|
|
3.0 |
4.0 |
| 7 |
|
Near
gale |
13.9
- 17.1 |
28
- 33 |
|
Sea
heaps up and white foam from breaking waves
begins to be blown in streaks along the direction
of the wind. |
|
|
4.0 |
5.5 |
| 8 |
|
Gale |
17.2
- 20.7 |
34
- 40 |
|
Moderately
high waves. Edges of crests begin to break
into spindrift. |
|
|
5.5 |
7.5 |
| 9 |
|
Severe
gale |
20.8
- 24.4 |
41
- 47 |
|
High
waves. Crests of waves begin to topple, tumble
and roll over. Dense streaks of foam along
the direction of the wind. Spray may affect
visibility. |
|
|
7.0 |
10.0 |
| 10 |
|
Storm |
24.5
- 28.4 |
48
- 55 |
|
Very
high waves with long over-hanging crests.
Streaks of foam form great patches. 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. |
|
|
9.0 |
12.5 |
| 11 |
|
Violent
storm |
28.5
- 32.6 |
56
- 63 |
|
Exceptionally
high waves (small and medium-size ships might
be for a time lost to view behind the waves).
The sea is completely covered with long white
patches of foam. The edges of the wave crests
are blown into froth. Visibility affected. |
|
|
11.5 |
16.0 |
| 12 |
|
Hurricane
(over) |
oltre
32.7 |
oltre
64 |
|
The
air is filled with foam and spray. Sea completely
white. Visibility very seriously affected. |
|
|
14.0 |
- |
