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    Re: Level of observation accuracy in medium seas
    From: Dave Weilacher
    Date: 2004 Jul 23, 06:42 -0500

    Hi Jarad;
    
    Can you point me to your source for Noaa wave height definition?
    
    Dave W
    
    
    -----Original Message-----
    From: Jared Sherman 
    Sent: Jul 22, 2004 9:34 PM
    To: NAVIGATION-L{at}LISTSERV.WEBKAHUNA.COM
    Subject: Re: Level of observation accuracy in medium seas
    
    Dave-
     <50 foot waves with a mile between peaks.  I take my shot when my boat is
    at the top of a wave.  This is easy to tell because I can actually see a
    horizon.  The horizon I see is 8 miles away.>
     Seems like short horizon. NOAA says that waves are measured from the sea
    level, not from the trough to peak, so are you talking about real fifty foot
    waves, or "real" 50 foot waves, which most sailors would call hundred
    footers?
    
    If the former, you're observing from 25' above sea level, figure ten more
    for your deck and standing eye height, since you've got a good enough grip
    to rider those doggies. That's 35' asf now, about your eight miles.
    (7.9+)
    
    Nah, you're only in 25' waves, that's the problem. Wait for rougher weather,
    you'll get a better horizon.
    
    But you could certainly figure the math. A sphere (close enough) 25,000
    miles in circumference, two points 8 miles apart on that. Change the radius
    of one by the 25' your far wave is blocking you...run some tangents and
    angles..."A simple exercise left to the reader."
    
    Just remember, you're only in 25' waves.
    
    
    Dave Weilacher
    .US Coast Guard licensed captain
    .    #889968
    .ASA instructor evaluator and celestial
    .    navigation instructor #990800
    .IBM AS400 RPG contract programmer
    
    
    

       
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