Electronic Chart issues

[Mainstreet]

I have GarminBlue chart, INavX and Navionics HD on my iPad. I've noticed that when viewing the area from Memory Rock to little Bahama Bank they don't agree with each other as far as soundings go. That's a critical issue in my book. Anyone want to weigh in on which one is most accurate?

[MarkJ]

I won't comment on which is more accurate as I haven't been there for 3 years.

But whenever one notices and discrepancy a cross different formats then I don't trust none of them.

Go slow.

[Mainstreet]

That is precisely my point. What DO you trust? Are there detailed admiralty charts of this area of the Bahamas available? And, are they current. I once bought an admiralty chart of Barbados from a chandler in Bridgetown. He claimed it was the most current and it was dated 1850 approximately!

[Neptune's Gear]

Listen to MarkJ, he's 100% spot on.
In fact I never rely 100% on one source of info. Trust, but verify.

Two sources (Chart and radar) are ok, three or four is better - Chart, Radar, Soundings, Mk 1 eyeball, Coastal piloting (transits etc), Google Earth etc are some of the others

[sck5]

believe Garmin. They have a license from Explorer charts. Do not believe Navionics. At all.

The only thing to really believe, however, is your sounder and a good pair of polarized sunglasses

[Neptune's Gear]

There are no accurate charts in some places. You have to get used to that. All the systems have areas where they are inaccurate. Don't take anyone's advice to believe one source without verification.

[hpeer]

Yup. Looking at next season cruising area on the most recent CHS charts I found the note that this one chart was based on French soundings collected in 1870ish.

[Mainstreet]

Those ancient soundings are fine for rocks and ledges but the issue I'm concerned about is shifting sand banks and coral outcrops all of which tend to move or grow.

Can I trust the navigation bouy system in the Abacos?

[clownfishsydney]

We have Navionics Gold for Australia. It has three significant errors that we identified on our trip last year to North Queensland. If we had followed blindly the chartplotter when entering three ports/reefs, we would have run aground each time. Very poor quality control.

[Mainstreet]

I've noticed that about Navionics also. While sailing the Gulf of Mexico, the Florida keys and the Atlantic coast I've found more than a few times when the Navionics charts were in error. I've tried to contact them to advise them of the fact but can't seem to reach them. You would expect that the iPad app would have a hotline connection to address error. I like their auto routing service but I cross check it with both the Garmin software and my Raymarine E80 for confirmation.

When sailing in US waters I always use NOAA charts and CHS charts when in Canadian waters as the gold standard. My concern is whether there whether there is a similar chart reference for The Bahamas.

[denverd0n]

Originally Posted by Mainstreet

What DO you trust?

You trust your own (hopefully calibrated) depth sounder, and your eyes. And, as Mark said, you go slow. Putting your complete trust in ANY chart--electronic or not--is a good way to get yourself into trouble.

[ranger58sb]

Originally Posted by Mainstreet

I have GarminBlue chart, INavX and Navionics HD on my iPad. I've noticed that when viewing the area from Memory Rock to little Bahama Bank they don't agree with each other as far as soundings go. That's a critical issue in my book. Anyone want to weigh in on which one is most accurate?

Above subsequent discussion notwithstanding...

Are all three of your applications set to display in the same measurement -- feet, meters, fathoms, whatever?

I resume these are all vector charts? If so, have you at least compared those against the NOAA raster charts? (Which of course may be old soundings, too...)

-Chris

[hpeer]

NOTE ..... NO DIRECT KNOWLEDGE

Elsewhere on this site have recommended the Van Sant book (Gentlemans Guie to the Thorny Path or thereabouts) as best advice. IIRC Van Sant recommends Explorer Chart Books and Wavyline electronic charts.

Since I'm planning a trip South I've been looking into this a bit. I have a Raymarine plotter with Navonics charts. Not impressed with them in the areas where over sailed. I much prefer Inavex.

Explorer does not distribute their charts directly but licenses them through others. Ditto Wavyline.

Since I've heard so many on this board recommend Explorer and Wavyline I'm inclined to that direction. I've used Fugawi 4.5 for a number of years and they have always been real responsive and easy to deal with. I also use Inavex.

Fugawi/X-Traverse a wide variety of charts including Explorer and Wavyline.

For those reasons I'm going to get my charts through Fugawi/X-Traverse.

Now none of this answers you question directly. It just seems the consensus of opinion is Explorer/Wavyline are best. But, as always, final decisions rest on our shoulders. Good luck to both of us.

[belizesailor]

Originally Posted by Mainstreet

I've noticed that about Navionics also. While sailing the Gulf of Mexico, the Florida keys and the Atlantic coast I've found more than a few times when the Navionics charts were in error. I've tried to contact them to advise them of the fact but can't seem to reach them. You would expect that the iPad app would have a hotline connection to address error. I like their auto routing service but I cross check it with both the Garmin software and my Raymarine E80 for confirmation.

When sailing in US waters I always use NOAA charts and CHS charts when in Canadian waters as the gold standard. My concern is whether there whether there is a similar chart reference for The Bahamas.

I have contacted Navionics before about major innaccuracies...they are not interested.

[cagney]

If you had mentioned Bahamas in the headline there would have been many more answers.......
The general consensus seems to be that the Explorer charts are the best for Bahamas. I agree with that. To get full coverage there are presently two choices: either the Explorer Chartbooks or the correct version of Cmap. See more on Welcome to Explorer Chartbooks

Garmin currently only use explorer for some parts of the Bahamas. See the explorer website.

Wavey Lines coverage is also good, but last year I found a couple of errors.
You can check out their coverage on Transas Isailors page Transas iSailor Chart Folios. Transas has licensed wavey lines charts for the Bahamas.
Use this feature to compare with your two chart sources.

Navionics is dangerous to use, especially in Bahamas. They have an arrogant attitude to errors and updates. Some coverage and updates are known to be pure imagination.

Official charts from NOAA,NGA or UKHO are of very little use except for entering a few major commercial ports.

Do not trust any navigational aids, buoys, markers, lighthouses etc. You may see buoys in real life that are not on any chart and vice versa.

Do not expect surveys, updates and charts to the same standard as in US.
It may take a long time before any changes in sandbars and depths in general, after Matthew, are known.
So ....
As already mentioned, learn eyeball navigation........

/Thomas