If the GPS Fails I'm Riding the Isobars Home

Working the problem the other way. Instead of plotting the position on the wx chart and looking at the weather just do the reverse. Look at the weather and plot your position. Navigate using the wind speed/direction and air pressure.

It would be like using knowing your altitude and a topo map to find your way in the woods. You’d need both current weather maps and the forecast. Should be good for 96 hours of navigation.

Assuming of course the navigator is the “good seaman” of legend.


Now just add a sounding, and you’ve got yourself an Observed Position.


The other day I was thinking about the phrase “using all available means”.

The phrase is only pertinent in cases where the reliability of the information is low enough that more data is needed to obtain an EP of sufficient total reliability.

It applies less today in some case for example pilot waters where there is more than enough reliable information, to continue to seek info would be at the cost of attention best used elsewhere.

In low information situations it’s a matter of putting the appropriate weight on data of varying characteristics.

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the you guys will just ask Google…

As long as you stay 100 milles from shore…