Hello all
So if i am in a 24' trailer sailer with my head hight aprox 5' off the
water and all i can see is sky and the side of the wave and a 80.5 meter
light house 1.5nm away is out of sight in the troughs (worked by
sounding and bearing) LOCATION:
Latitude 32° 0.5' S, Longitude 115° 30.1' E
i estimated 8' to 12' breeze was forcast 30/35 kn i was knocked down
twice and had a ball.
http://www.lighthouse.net.au/lights/....htm#Operation
shaun

Ryk wrote:
On Mon, 20 Dec 2004 02:56:36 GMT, "Roger Long"
wrote:


The method for getting accurate wave height data from a boat is to know the
height above the waterline of some points at different heights. You then
stand on one and stretch or crouch until you find yourself looking across
the tops of the waves when the boat is in the trough. It usually takes a
few waves to get an average but it's quite striking when you get the right
position. You then measure from eye to feet and add it to the height known.
That's the average wave height.


I'm reassured. That's the approach I take when trying to make
estimates and I'm usually fairly consistent with what the Coast Guard
is broadcasting. I was wondering if you had some other secret trick.


I've often been amused to have even fairly experienced sailors say that the
waves must be eight feet. I usually don't point out that our eyes are
perhaps six feet above the surface and we can still see all the tops when we
are down in the trough.


Losing all the shoreside lights in the troughs can be quite dramatic,
and they are definitely higher off the water than the rest of the wave
crests.

Ryk

That sounds like fun. However, the fact that the lighthouse is out of
sight is meaningless - that could occur in a modest swell. 80 meters
at 1.5 miles is roughly 3 parts in a hundred, or a 2 degree elevation.
Even is you have a 5 foot eye height from the water line (doubtful
unless you're standing) if you're in the trough of a 10 foot swell the
light would not be visible if the wavelength is under about 200 feet.
If the wave height is only one foot above eye level the view of the
light is cut if the half wavelength is under 30 feet.


shaun wrote:
Hello all
So if i am in a 24' trailer sailer with my head hight aprox 5' off the
water and all i can see is sky and the side of the wave and a 80.5 meter
light house 1.5nm away is out of sight in the troughs (worked by
sounding and bearing) LOCATION:
Latitude 32° 0.5' S, Longitude 115° 30.1' E
i estimated 8' to 12' breeze was forcast 30/35 kn i was knocked down
twice and had a ball.
http://www.lighthouse.net.au/lights/....htm#Operation

shaun

Ryk wrote:

On Mon, 20 Dec 2004 02:56:36 GMT, "Roger Long"
wrote:


The method for getting accurate wave height data from a boat is to
know the height above the waterline of some points at different
heights. You then stand on one and stretch or crouch until you find
yourself looking across the tops of the waves when the boat is in the
trough. It usually takes a few waves to get an average but it's
quite striking when you get the right position. You then measure
from eye to feet and add it to the height known. That's the average
wave height.



I'm reassured. That's the approach I take when trying to make
estimates and I'm usually fairly consistent with what the Coast Guard
is broadcasting. I was wondering if you had some other secret trick.

I've often been amused to have even fairly experienced sailors say
that the waves must be eight feet. I usually don't point out that
our eyes are perhaps six feet above the surface and we can still see
all the tops when we are down in the trough.



Losing all the shoreside lights in the troughs can be quite dramatic,
and they are definitely higher off the water than the rest of the wave
crests.

Ryk