Re: save waypoints
I don't think any of them save a waypoint automatically, you have to at least push a button. It is then saved to system memory until you have to change the batteries which is often. You get a DC power cord with the H20 then at the end of the day you can save all your waypoints to a SD or MMC card. They can then be recalled whenever you need them.
This is correct for the H20c, and I assume for any brand. Waypoints are manually set either on the water, or on the couch.
For instance...I was stopped about 2 miles from shore in the Gulf of Mexico, when I managed to lose my glasses overboard. I immediately set a waypoint, with the intention of returning to the spot with a friend that had the diving gear to look for them. The depth was around 18 feet. I never made the retrieval effort, but my GPS would have returned me to within 13 meters (I am guessing here) of my glasses. Some people use the waypoint to mark good fishing spots....
You can also use the NautiPath nautical card in the H20c to set waypoints from your couch. You just send the cursor to the area that you plan to boat in...the various buoys, channels, and obstructions, are displayed...you just move the cursor on the path you want to take, setting waypoints at several key points. When you launch the GPS will direct you to the first waypoint...alert you when you arrive...and then direct you to the next, etc.
Plot trails are recorded automatically, and are great to retrace your way home. This is from the Lowrance site:
"A plot trail appears on your GPS screen as a line that flashes once per second, for easy viewing. Your GPS plots a trail by placing a position marker dot on the screen every three seconds as you travel. (This can be adjusted from one dot per second to one dot per 30 minutes, or you can update your trail by distance instead of time.) With menu commands, you can save, recall and navigate a trail (forward or backward) just as you would a route. Navigation steering information is provided in either a compass rose display (with an arrow pointing out the correct travel direction) or as a dotted line on a unit's map display. Or, you can skip the navigation commands and simply retrace your path following the flashing plot trail on the map display."
http://www.lowrance.com/en/Support/Tips-and-Tutorials/GPS-Tutorial/
When you set a waypoint while the GPS is making your plot trail, the waypoint shows up on your plot trail as a distinct dot.
Happy boating!
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