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    Re: Cel Nav!
    From: George Huxtable
    Date: 2004 Jul 27, 09:52 +0100

    This is a note, mainly to say how much I enjoyed Robert Gainer's piece  of
    18 July, under threadname "Cel Nav!", which he dismissed as "just some
    ramblings about sailing". If he has more such ramblings, I, for one, would
    be really interested in reading them.
    
    I thought the account of his rescue by "Hagen" showed a remarkable feat of
    seamanship by both parties: in meeting-up on the basis of astro
    observations, and then in the haulout, of both Robert himself AND his
    vessel!
    
    His story about mistaking the Moon, rising out of the mist, for a
    searchlight, rang true to me. After a long period without sleep, I have
    made exactly the same mistake, and like Robert, felt a complete fool about
    it afterwards. On another occasion, panic ensued from what seemed to be a
    rapidly approaching masthead light on a misty night, which turned out to be
    an aircraft's landing-light, as it made its approach to Jersey airport.
    
    Some, like me, get sufficient kicks out of sailing a small boat in
    continental-shelf waters to feel the need to go ocean cruising: but that
    doesn't diminish our respect for those, like Robert Gainer, that do.
    
    Just one aspect of his contribution had me puzzled, in which he said-
    " The mist on the Grand Banks meant that with my height of eye there was a large
    amount of time that no horizon was available to me. In fact on that boat my
    height (6 feet) of eye was so low that any kind of weather made it hard to
    get a shot."
    
    To me, those are circumstances (perhaps the only circumstances) in which
    the small-boat navigator has a positive ADVANTAGE over his counterpart in a
    big ship. I don't think I could put the matter better than Squire Lecky
    does, in his "Wrinkles", in which he says-
    
    ====================
    
    "THE SEA HORIZON.
    
    Every seaman knows that by going aloft in clear weather his range od view
    is extended, and that on account of the Earth's curvature the visible
    horizon recedes from him the higher he goes. In like manner, by descendinf
    downwards towards the surface of the water, his range of view is lessened,
    and the horizon approaches him. Advantage can be taken of this to get
    observations in foggy weather. By sitting in the bottom of a small boat in
    smooth water, or on the lowest step of the accommodation ladder, the eye
    will be about two feet above the sea level, at which height the horizon is
    little more than a mile and a quarter distant, so that unless the fog is
    very dense, serviceable observations are quite possible.
    
    The writer, on three different occasions, when at anchor off the River
    Plate, during fog, has been enabled to ascertain the ship's position in the
    way described, and after verifying it by the lead, has proceeded up to Mone
    Video without seeing land..."
    
    He goes on to summarise-
    
    "In fine clear weather, take your observations from the highest convenient
    place, say the bridge...
    
    ...In thick or misty weather take your observations from as low a point as
    possible, and in all cases apply the correction for height of the eye
    corresponding to what it is known to be  at the spot where the observaton
    was taken..."
    
    ==================
    
    It seems to me that the circumstances Lecky refers to are precisely the
    same as those that Robert Gainer was referring to on the Grand Banks. In
    which case, any difficulties he was experiencing  in seeing a horizon from
    his low height-of-eye would have been far worse to a navigator on a larger
    vessel, observing from higher up. I wonder if he has any comments about
    that.
    
    I do recommend Lecky's "Wrinkles in Practical Navigation" (my edition being
    1920, but the first was 1881) as being full of commonsense and real
    homespun wisdom, well written. making for easy reading. He covers well the
    overlap period between sail and steam.
    
    George.
    
    ================================================================
    contact George Huxtable by email at george---.u-net.com, by phone at
    01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
    Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ================================================================
    
    
    

       
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