We use our Garmin chartplotter with intergrated overlaid RADAR to figure out where we are, and we have a completely separate PC based system with it’s own GPS and chart set.
In Baja, however, we primarily navigate by eye, because the charts are off by a lot (https://svbrightwater.wordpress.com/2013/02/26/finding-puerto-ballandra/). Superimposing the RADAR image on the chart is a big help, but it’s still a problem.
On the laptop, we use an open-source free program called OpenCPN as a chartplotter. They recently developed the ability to “harvest” “photo charts” from Google Earth, also for free. The best directions on the web to do this were put together by our friends the Hacking family on Ocelot: http://hackingfamily.com/Cruise_Info/Equipment/KAPFiles.htm.
Here’s what the basic charts look like. Notice that Pt. Ballandra is way, way, off.
We are able to grab an image from Google Earth and create a fake chart called a KAP file. Notice it’s located correctly.
We can grab images at any resolution by controlling the “height” on Google Earth, and the detail KAP charts also index flawlessly. We can also see the recent washout in the bay, and the resulting new shoal areas within the bay that almost caused us to go aground last visit.
We use a free program called Ugrib to get our wind and wave forecasts. Typically we just look at the wind, in 3 or 6 hour increments, overlaid on the OpenCPN charts. The standard wind notification uses arrows, pointing in the local wind direction. A long barb on the arrow is 10 knots, a short barb is 5.
OpenCPN added a new feature called “Particle Map” that adds colored bits that flow around the map following the air flow. It makes the map prettier, but it also makes it easier to see that this weekend might be a great time to start a trip from La Paz to San Diego – you could sail the whole way on one tack.