Depending what size card you have that will determine the amount of data that can be saved. I haven't had a chance to use this on the water yet so I am not sure exactly what it will be, but from what I have heard covering an entire bay is not a problem at all.

I don't think it will be very long before we see instant mapping on the units. I have heard some things that Navionics is working on and within a couple years I would expect to have it

-Lawren