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    Re: Can I Navigate Without an Assumed Position?
    From: Geoffrey Kolbe
    Date: 2017 Aug 26, 22:39 -0700

    The answer is yes - well, sort of.

    I have a 36 inch diameter blow-up globe which I use for demonstrating the principles of celestial postition fixing. I have a large set of protractors which has a small rounded cork stuck on the sharp point and a white-board marker pen for the pen. 

    The protractor is adjusted for the co-altitude using the latitude scale on the globe. The cork-point is placed on the GP of the celestial object and a circle drawn on the globe. This is repeated for the sightings for two more celestial objects.

    The circles will all meet - or form a small cocked hat - at a unique position, which is where you are.

    Accuracy, probably +/- 20 nautical miles.

    The globe can be deflated and stored in a relatively small space, so in principle, it is a practical and simple device for deep ocean sailing - and it does not require an assumed position!

    Geoffrey Kolbe

       
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