So the GPS vs sextant debate finally found its way onto the peaceful A4 forums. Although a GPS receiver is not among the poll choices, it probably should be. GPS plays a role in calculating fuel consumption and remaining, for example.
My take, much honed after years of debate on this point and teaching navigation: GPS (or one of the other electronic satellite navigation positioning systems) is our primary positioning tool now in both coastal and offshore navigation, but the great navigation luxury in our electronic age is the ability to have a completely independent backup positioning system. GPS can fail, either on board or in the system outside the boat. Near shore, ability to do positioning with a hand-bearing magnetic compass, sounder and dead reckoning works fine. Offshore, the only practical independent backup solution for a recreational boater is celestial navigation. So I agree fully with those posters who use GPS primarily, but intend to learn CN for offshore backup.
A sextant is a fine way to snap bearings in coastal navigation, but a handheld compass is a more practical solution for manual positioning in the rare event of GPS failure, or to check a GPS positioning in tight quarters near hazards. Using a sextant for horizontal and vertical angles near shore takes a lot of practice and requires a 3-legged protractor.
One big advantage of taking a celestial navigation course like the USPS Junior Navigator/Navigator package is better understanding of navigation and positioning generally: it is not all about the sextant, athough that's the main content. Even if graduates never need celestial navigation in real life, the discipline and knowledge learned for general navigation can pay dividends. GPS merely automates (and hides under the hood) the same mathematics used in celestial navigation, except using man-made satellites instead of natural celestial bodies.
Quote:
Originally Posted by Gordo
there is NO VERIFIED CASE where the GPS system gave bad info.
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Depends what one means by bad info I guess, but there are many well documented examples. Fortunately they are infrequent, but the results have been spectacular in some cases, minor and easily recoverable in others. Like the day we were steaming along a river in the US and the chartplotter went blank because the electonic chart was missing that sector of the river for half a mile. The e-chart was white with black crosses. And cases in the Caribbean where GPS positions did not match the chart owing to datum differences.