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    Re: beginner
    From: Willem Piccer
    Date: 2005 Oct 2, 12:29 +0200

    I suppose it is a personal matter: I feel more happy with a little bit (
    more) weight and as a result of that more inertia.
    Less weight can also be a selling argument for instrumentmakers.
    Regarding your "skeleton"argument: if you make a disc like sextant it will
    be very prone to windinfluence
    A little bit out of the "navigation lane" : with bicycles in a race ( time
    trials) there is also the argument of using "open"wheels or "disc"wheels
    because with the wind in the wrong direction the disc wheels have a negative
    influence.
    I am Dutch that's why I bring up the bicycle!
    
    I short to me: skeleton frame with a certain weight is perfect!
    
    Willem Piccer
    
    ----- Original Message -----
    From: "george huxtable" 
    To: 
    Sent: Wednesday, September 28, 2005 1:05 AM
    Subject: Re: beginner
    
    
    > At 10:56 19/09/2005, Willem Piccer wrote, about the weight of an observing
    > instrument-:
    >
    > >Weight is something which plays a minor role in the discussions we see
    here
    > >about the plastic sextant but to me it is important.
    > >
    > >If you use your sextant on a platform which is not stable than a sextant
    > >which has a certain weight will help you to obtain a more accurate
    > >observation because it is more stable.
    > >I know there is a sextant from John Bird ( around 1770) which has a
    "stick"
    > >on the backside to make it more stable.
    > >
    > >I suppose there is an optimum weight for a sextant : on one side not too
    > >heavy to handle and on the other side heavy enough to obtain a good
    > >observation.
    > >I remember when we started to use these light East German sextants that
    this
    > >was exactly  what was noticed: easy to lift but more difficult to make a
    > >good observation
    >
    > =======================
    >
    > I've seen that sentiment expressed before, by other seasoned professional
    > mariuners, and I would like to understand the basis for it. Why should a
    > heavy sextant be more stable, I ask (as someone who only ever owned a
    > plastic sextant, but has used others)? I respect the views of those who
    > have much more experience than I do, but remain as yet unconvinced.
    >
    > After all, the windage on a sextant is just the same, when made of a light
    > material or a heavy one, if they are the same shape and size. If a sextant
    > is physically smaller, as some yachtsman's models are,  then wind forces
    > will be less. True, a heavy sextant will have more inertia, so it resists
    > initial movement, but when moving with the ship's roll, then it acquires
    > extra momentum, which makes it harder to bring it to a stop.
    >
    > Sextant makers all seem to go to a lot of trouble to skeletonize the
    frames
    > of their instruments. If there was as advantage in having a heavier
    > instrument, why would they bother to do so?
    >
    > The clinching argument, to my mind, against Willem's view, is that if
    > weight was a real advantage, mariners would "improve" their lightweight
    > instruments by simply adding lead ballast, to make the thing more
    "stable".
    > I have never heard of this being done, to any sextant, though it would be
    > easy to do in practice. Why not, then, if the extra weight would make it
    > somehow better? Convince me that it would.
    >
    > =======================
    >
    > I've missed recent Nav-L discussions, having been away on a family holiday
    > (four aboard) on a hired motor-cruiser on the River Charente, in
    south-west
    > France. For me, a real change, in that the only navigational decision was
    > whether to set off upstream and return downstream, or vice versa. It made
    > for a good holiday, but reinforced my preference for salt water, and
    sails.
    >
    > George.
    > ===============================================================
    > Contact George at george@huxtable.u-net.com ,or by phone +44 1865 820222,
    > or from within UK 01865 820222.
    > Or by post- George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13
    > 5HX, UK.
    >
    
    
    

       
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