Douglas Sea Scale
The Douglas Sea Scale is a scale which measures the height of the
waves and also measures the swell of the sea. The scale is very
simple to follow and is expressed in one of 10 degrees.
The
Douglas Sea Scale, also called the International Sea and Swell
Scale, was devised in the 1920s by Captain H.P. Douglas, who later
became
Vice Admiral Sir Percy
Douglas and Hydrographer of the Royal Navy. Its purpose is to
estimate the roughness of the sea for navigation. The scale has two
codes: one code is for estimating the sea state, the other code is
for describing the swell of the sea.
|
State of the sea (wind sea) |
|
|
|
| Degree |
Height (m) |
Description |
| 0 |
no wave |
Calm (Glassy) |
| 1 |
0 - 0.10 |
Calm (Rippled) |
| 2 |
0.10 - 0.50 |
Smooth |
| 3 |
0.50 - 1.25 |
Slight |
| 4 |
1.25 - 2.50 |
Moderate |
| 5 |
2.50 - 4.00 |
Rough |
| 6 |
4.00 - 6.00 |
Very Rough |
| 7 |
6.00 - 9.00 |
High |
| 8 |
9.00 - 14.00 |
Very High |
| 9 |
14.00+ |
Phenomenal |
|
|
|
| Swell |
|
|
|
|
|
| Degrees |
Description |
|
| 0 |
No Swell |
|
| 1 |
Very Low (short and low wave) |
|
| 2 |
Low (long and low wave) |
|
| 3 |
Light (short and moderate wave) |
|
| 4 |
Moderate (average and moderate
wave) |
|
| 5 |
Moderate rough (long and
moderate wave) |
|
| 6 |
Rough (short and heavy wave) |
|
| 7 |
High (average and heavy wave) |
|
| 8 |
Very high (long and heavy wave) |
|
| 9 |
Confused (wavelength and height
indefinable) |
|
See also:
Douglas-Appleyard Arcless Sextant
Douglas navigation
protractor
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gratefully accepted
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