Lowrance 520C GPS

I have the 520C and a navionics chip to go with it. When I have the unit zoomed in on a waypoint trolling the acquire speed for the gps is very slow. I have read that it is due to the detail on the navionics chip that is causing the gps to acquire slow. I have not read if there is a fix or not. Do any of you know?

thanks

When my 520 is not full of water, it works just fine...even the gps is good.

Now, if I could ever get me a Lowrance unit that doesn't take on water EVERY TIME IT RAINS, I'd be a happy camper.

aj