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..
But, but, but, Richard ....I _want_ to be able to sail into my slip
under 0/0 ISR (Instrument Sail Rule) conditions!  :)
1-3 meters ain't bad, eh?

We can't stop progress, guy, regardless of "emotions". So many land
services are setting the pace. We benefit.

Tony

"Richard B. Emerson" wrote:
>
> Philip OUVRY writes:
>  > For maritime users in small craft a GPS accuracy of 100 metres is
>  > more than sufficient.  Provided you can find the fairway or safe
>  > water buoy at the approaches to ones destination or the entrance to
>  > the harbour, it is far safer to navigate by sight (i.e. pilotage)
>  > rather than by 'head-down' reference to the GPS.
>
> Slavish adherence to any one source of navigation information, be it
> the display of a GPS or the human eye, will sooner or later lead to
> problems.  The prudent mariner will continually compare one source of
> information with another to be sure of having reliable information.
>
>  > Out at sea an accuracy of one mile is quite sufficient.
>
> Er, I'd even argue that three miles is quite enough.
>
>  > There are occasions when a greater accuracy would be useful such as
>  > an anchor position in a crowded anchorage.  There is no real need
>  > to know the boat's position to an accuracy of 30 metres or less.
>
> While perhaps 15 meter accuracy seems superfluous for small boats, one
> of the more important benefits of SA being disabled is speed accuracy.
> Remember that every time the satellites danced and, albeit briefly,
> had 30 foot sailboats moving at 20 or 30 knots, speed averaging and
> log functions were corrupted by these false motions.  Without SA,
> speed and distance covered are going to be closer to reality than when
> SA was enabled.
>
> Rick
> S/V One With The Wind, Baba 35

   

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