My new B&G Zeus3 accepts both C-Map and Navionics charts, which one to choose? The top of the line, C-map Max-N+ (now REVEAL) or Navionics Platinum+, offers a lot of features of little interest to me. Pseudo 3D, relief images of the bottom, too colorful. (march 2022: C-Map renamed its product Max-N+ –> REVEAL
There is also a price argument. Navionics is more expensive, there is a price increase of 50% between Navionics+ and Platinum+ and a smaller covered area. For Navionics+ the coverage of “large” is UK + Ireland + Netherlands (€ 243 in 2020). You need 2 Platinum+ cards (UK + Ireland and NL for 2 * € 365), which is an increase of 300%. The subscription costs 50% of the purchase price annually.
C-Map is more affordable, the largest covered area is called Continental Charts or Extra Large. For example Northern Europe for € 233 and the Pacific side from Panama to Canada € 179. There product is renamed form Max-N to DISCOVER. The subscription costs 50% of the purchase price annually.
C-map is therefore the winner of this competition, but you have to look at your sailing area. For us: Vietnam to Japan, the crossing to Canada, hoping to Panama, Micronesia towards NZ and Australia, an unusual route that crosses both densely populated and sparsely populated areas.
And then it is clear that island hopping from the very south of Japan to Central Japan is not covers by a C-map Continental chart. Look for the Wide (Costal) equivalent or if absent buy a Navionics map. The same goes for Micronesia towards NZ.
Accuracy
Navionics and C-map provides maps for South Pacific toward NZ, but it is well known that they are not very accurate. Looking for alternatives there is one valid option, Satellite Charts or Overlays. If you are the owner of a Navico plotter, like B&G, then you can integrate them on your device, otherwise you an alternative like OpenCPN or Ovital or .., I still look to sailors forums for input on converted maps of that area. So there are a few ground rules for navigating ‘uncharted’ waters.
- Always search for information before creating a route;
- Zoom in or activate the correct number of detail layers on your chart plotter;
- If possible, activate an alarm depth of ~ 5 to 10 meters, quickly respond with an opposite heading when sounding;
- Put way-points 5 NM away from your destination, obstacle, reef barrier;
- Never approach at night, go slow (I broke this rule a few times);
- Use satellite imagery to aid in your navigation at that particular entrance.
OpenCPN with satellite images
New features on the top version of C-Map and Navionics are Aerial Photos. But not available in C-map Max-N + Continental charts and for Navionics Platinum + only in relation to SonarCharts, the community database. Guess what, you have to be online and the coverage of sparsely populated or economically uninteresting areas is low.
So satellite overlays is it. Satellite overlays can be done in a number of ways. It all started with:
- Paul Higgins who wrote GE2KAP (Google Earth to KAP, Chart Image Files) started the Satellite Overlays movement. Known, works with old version of GE, Windows oriented, see http://gdayii.ca/index.php . Currently known as SAT2Chart.
- SAS.Planet, a Windows standalone program to download images from different providers, also see my article on how to integrate SAS.Planet images on the B&G Zeus3.
- Venture Farther, is a plug-in on top of OpenCPN, works with a database in which images are stored. A great feature from the same programmers is a tool for uploading your NMEA depth data from your course as a favor to other users. For more information Vfkaps Charts on OpenCPN or their own website at https://www.venturefarther.com/.
I will do some research on SAS.Planet, especially using its offline. To be continued …
Edited, march 2022
