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Garmin vs Navionics beware

Discussion in 'Electronics' started by 993RSR, Jun 4, 2020.

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  1. 993RSR

    993RSR Senior Member

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    Two charts of the same area. ICW inside Cumberland Island. Top chart is a Navionics chart. Bottom chart, showing my friends southbound track is an updated Garmin plotter chart.
    navionics Cumberland.jpg cumberland garmin.jpg
  2. Sea Gull

    Sea Gull Member

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    That is scary! My understanding is that Garmin uses Navionics data for their charting, so would think the latest Navionics branded chart would have the same information.
  3. 993RSR

    993RSR Senior Member

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    Yea almost cost "my friend" :( some running gear. Garmin charts are way different than Navionics. There must be a way load them with Navionics charts.
    This was a situation that if you followed the markers as you see them you would have been in 10-12' of water, no issues. The Garmins have the markers correct but the white water and swamp are in the wrong spots.
  4. Pascal

    Pascal Senior Member

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    It s been a while since I ve run that stretch of the ICW but I remember it to be a known Confusing spot. Yes the chart is confusing but it looks like your friend missed 60A and the one just above taking a shortcut to 62A

    whenever you see a number of markers named with a letters after the number, it s a warning sign that you re in a changing area with added buoys or markers

    In the Bahamas though, it’s the other way around. Navionics is pretty bad and since Garmin has dropped explorer charts data both are to be avoided. They are dozens of spots in the Exumas where Navionics is way off. Explorer charts on C-Map is the only E charts to trust in the Bahamas
  5. NYCAP123

    NYCAP123 Senior Member

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    That's scary. It doesn't even look like the same area. A good lesson about charts being a "Guide" not gospel and the dangers of running at night or during reduced visibility. Nothing beats a good set of eyes. When was that Navionics chart updated?
  6. rtrafford

    rtrafford Senior Member

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    From my CMap mobile app. I'm assuming the CMap aboard is similar...

    IMG_9409.PNG
  7. Pascal

    Pascal Senior Member

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    475C83C7-5641-4B05-86E3-CCC853831D1E.jpeg Aquamap is actually the best there it seems.

    475C83C7-5641-4B05-86E3-CCC853831D1E.jpeg
  8. 993RSR

    993RSR Senior Member

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    If I did not have the plotter with wacky graphics I (I mean my friend) would have followed the markers and had no problem.
  9. Capt J

    Capt J Senior Member

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    I've seen the new Garmins I have been dealing with still have the good Garmin charts. I did have a recent Navionics chip in a Simrad and it was so bad in the Bahamas that I took it out of the machine and replaced it with a C-Map. I did see some of the new style charts in the latest Garmin and they sucked, had a bunch of depth lines in them like a fishing chart and very hard to read. I don't know why everyone has to change the look of the charts when it was perfect and had the perfect shading like the Aquamap shown above where the channel is white and the rest blue.
  10. rtrafford

    rtrafford Senior Member

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    I think if I came across that intersection late at night after a long run I'd pull over, drop a hook, pour a rum, and call it a day...
  11. Capt J

    Capt J Senior Member

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    It's not as difficult as it looks if you simply look at the markers. They're close enough together that there's no guessing. Unless you're a new boater and don't know to follow the markers 1st, and your chartplotter 2nd.
  12. Pascal

    Pascal Senior Member

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    It s called magentasis They blindly follow the magenta line
  13. jsschieff

    jsschieff Senior Member

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    I installed a Garmin and a Raymarine on a small cruising boat I had and found it really handy to see two different looks in tricky areas.

    Once the Garmin went blank in a narrow, complex channel on the west coast of FL that was new to me -- if I hadn't had the Raymarine fallback it would have been very uncomfortable to say the least. It turned out I had exceeded the boundary of an installed Garmin chart chip, but the unit started working again a mile or two later.

    On another boat I had the Garmin was utterly wrong almost all the time cruising the Erie canal -- it usually showed the boat cruising 40 or 50 feet inland. Not a problem except in some larger waterways and lakes where the channel was not so easy to eyeball.
  14. Oscarvan

    Oscarvan Senior Member

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    Sounds more like a receiver/processor/map shift issue than a charting issue.
  15. Capt J

    Capt J Senior Member

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    It is quite common for electronic charts (which are scanned from paper charts) to be off in the chip like that. That is why one can never 100% trust an electronic chart, that shift is throughout that entire chart in the electronic chartplotter.
  16. jsschieff

    jsschieff Senior Member

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    The Erie Canal chart problem happened quite a few years ago. The Garmin was only off badly in or near the Erie Canal -- it seemed accurate on Lake Erie and accurate in the Hudson River, Long Island Sound and Narragansett Bay.
  17. Oscarvan

    Oscarvan Senior Member

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    Are you talking electronic raster charts? Don't believe vector charts are scanned. They are data bases.
  18. Capt J

    Capt J Senior Member

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    Vector charts are still taken from paper charts, so they're only as good as the data that is put into it. I see more distance/location issues from the Vector charts. I can't tell you how many times I've run yachts right across land with them!