Hi George,
That's correct. I set the HB recording as soon as I've left the marina and don't even bother looking at anything other than 2D or the GPS (so I can make sure that I'm not going over the same tracks as an earlier voyage, as I leave them on the machine.)
On playback, you can adjust range, si sensitivity, colour, left or right screen etc. You can take screenshots, magnify and create waypoints too.