
Travel times from the main hawaiian buoys to the Island of O'ahu
Note :
In deep water, wave energy travels at a speed that only depends on the
average period of the swell train. It doesn't depend on the size of the
swell, just on the period, this is what oceanographers call the dispersive
nature of deep water waves.
Once in shallow water (between say 300 feet deep and the beach), this
is not the case anymore. The wave period will stay the same, but it will
slow down and steepen before it breaks. At that point the speed doesn't
depend on the wave period but only on the water depth (non dispersive nature
of shallow water waves). Near the break point, because the wave height
and the water depth are related, the speed of a wave also depend its size.
As the water between the buoys and O'ahu is very deep, the travel distances
below are computed for wave energy traveling in deep water.
Buoy 51001 (NW Hawaii)
Distance from Waimea Bay : 255 Nautical miles (170 nm from Hanalei Bay
Kauai)
Bearing from Waimea Bay : ~300 degrees (North-West)
The times are given for waves coming from 300 degrees.
|
Wave period
|
Travel time
|
|
14 seconds
|
12 hours
|
|
17 seconds
|
10 hours
|
|
20 seconds
|
8 & 1/2 hours
|
Buoy 51002 (S Hawaii)
Distance from Ala Moana Beach Park : 255 Nautical miles
Bearing from : Ala Moana Beach Park : ~180 degrees (South)
The times are given for waves coming from 180 degrees.
|
Wave period
|
Travel time
|
|
14 seconds
|
11 & 1/2 hours
|
|
17 seconds
|
9 & 3/4 hours
|
|
20 seconds
|
8 hours
|
Buoy 51028 (S Hawaii, on the Equator)
Distance from Ala Moana Beach Park : ~1300 Nautical miles
Bearing from : Ala Moana Beach Park : ~170 degrees (South-Southeast)
The times are given for waves coming from 170 degrees.
|
Wave period
|
Travel time
|
|
14 seconds
|
61 hours (2 1/2 days)
|
|
17 seconds
|
51 hours (~ 2 days)
|
|
20 seconds
|
43 hours(< 2 days)
|
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