Many people are being woo 'ed by the cheap Navionics (and Garmin I believe) apps for iPhones and iPads. I have been experimenting with using an Ipad as my principal chart plotter and have concluded that the concept is a non-starter.

I have been cruising the east coast of South America over the last three years from top to bottom (and back). The C-Map coverage on my chart plotter for many of the places I have been to has been non-existent. The Navionics cartography was infinitely more comprehensive. So I decided to experiment with using an iPad in a waterproof housing as my principal chart plotter, using iNavX chart plotting software and downloading Navionics charts. I also have a Vesper XB8000 WiFi AIS transponder that streams AIS data as well as all the boat 's NMEA 0183 or 200 data to the chart. In theory this gives you almost everything a dedicated chart plotter provides, but for a fraction of the cost (and you have all the other functionality of the iPad to boot). However, I have found that it is unusable as a principal chart plotter because:

1.In bright sunlight, the chart can barely be seen
2.In hot climes, just at the point when you need it most, the screen blanks out with a message saying it is too hot, and cannot be rebooted for at least 10 minutes
3.When the screen gets wet from rain or spray, the touch screen doesn 't work - it has to be wiped dry every time you want to do anything like zoom in or out.
4.During the day, even when plugged in to a charger, the draw from the software and the brightest setting causes the battery to slowly drain.

Whilst the arrangement is great as a standby that you can use, for instance, at the helm when conning in or out of anchorages, it is sadly not fit for purpose as a principal chart plotter. So back to the drawing board and the cheque book!

Tim Barker, S/Y Mina2

«[font=sans-serif]Have you had experience with inaccuracies on Navionics charts?[/font]»

Yes.
[ul][li]1. Guadalquivir river, just downstream from Seville: no indication of the overhead power cables existing on the river bypass nor on the city channel into the port.[/li][li]2. Tomás Mestre canal into the Mar Menor near Cartagena: Navionics had a fantasy that the channel was passable only by tender at two separate points. We draw 2.2 meters, went in w/o issue.[/li][li]3. Unnamed cove immediately N of Akra Khondri Pounda, N of Frikes, Ithaca (alternate description: second cove S from Agios Nikólaos Is.). Where Navionics says there are 28 ft., in reality there are 148 ft.[/li][/ul]
The first one, we reported, got a quick reply, and within two weeks our chartset had been updated to accurately include both sets of power cables. The other two, we haven't reported.

Navionics charts are our primary navigation tool because of the richness of detail, wealth of ancillary information, and ease of use. However, we don't trust Navionics more than we need to, and we cross check them against a _minimum_ of two other chartsets (currently, MaxSea TZ and Imray Navigator), sometimes three, plus satellite imagery from Ovitalmap for anchorages, plus forward-looking sonar at very, very slow speed when doubts still remain.
edited by Hasbun on 9/26/2017
edited by Hasbun on 9/26/2017