Navionics

[ex-Gladys]

There are a few good examples of sailing accidents where the MAIB investigation says "over reliance on electronic navigation". One of the Clipper boats went onto a reef in the Pacific ( the crew were rescued but the boat was a total loss) for a number of reasons:
1. The original survey underpinning the charts was carried out by Capt Cook, so the accuracy should have been treated based on the equipment available at that time.
2. The Plotter was reporting a high Horizontal Dilution of Position (the satellites in use were all low in the sky meaning that the accuracy of the plotter was severely affected)

 

[Sticky Fingers]

Yes. 'Over reliance' is generic to all plotters of course.

 

[Marmalade]

ipad with Navionics is good with the Axiom... download the RayControl software to allow your ipad to control the plotter and act as a repeater for it. Also (given a data source) the Navionics boating app can sync with the Axiom and update your charts and transfer routes and waypoints...

 

[requiem]

True, but also true of Imray and all others. It would be very useful to know, with actual facts not speculation, what is deficient about Navionics charts. My boat chartplotter is Simrad and uses Navionics charts. I use the tablet Navionics App and I use the web app for casual planning. What risks do I run?

One issue is that you have no idea about the quality of the chart data the way you can with ENCs and a proper charting system. Want to know when the area was surveyed? Good luck! I personally don't like the choice to present most nav aids in miniature, and would much prefer to simply take government charts directly, rather than have someone repackage them. At least NOAA does it right; one can pull down updated ENCs as soon as they're made available.

There are a few good examples of sailing accidents where the MAIB investigation says "over reliance on electronic navigation". One of the Clipper boats went onto a reef in the Pacific ( the crew were rescued but the boat was a total loss) for a number of reasons:
1. The original survey underpinning the charts was carried out by Capt Cook, so the accuracy should have been treated based on the equipment available at that time.
2. The Plotter was reporting a high Horizontal Dilution of Position (the satellites in use were all low in the sky meaning that the accuracy of the plotter was severely affected)

IMO electronic navigation offers useful benefits in reducing error and improving safety. The "check your brain at the door" approach to electronic charts, and treating them as inferior to traditional paper, does a disservice to future generations of mariners. Would traditional navigation training be considered adequate if basic concepts like a running fix were neglected? Would a radar class be considered adequate if the instruction mainly consisted of "blips are ships, and here's how to use MARPA"? Yet, such brevity seems considered sufficient for electronic charts.

That said, charts are charts, and any chart might be outdated or erroneous. Navionics appears to fix such when found, which is what you'd expect of any good chart provider. I will echo concerns about the sonar charts; without knowledge of the data's source one has no reason to treat them as a "more accurate" view of the bathymetry; this is a feature IMO better for fisherfolk than sailors. Finally, watch for user-edited features; I just spotted two buoys recently that AFAIK do not actually exist, and mistaking the actual ones nearby for them could set someone on the rocks.