Originally Posted by thefishingguy
... We are on a budget and a combo unit (fishfinder and GPS) will have to wait...
The topography feature is NOT for the fish but for the contours of bottom (primarily the shallow areas)u where one may run aground in a boat. It'll be similar to the contour lines of a marine chart.
Getting a marine GPS will be more preferable than repairing a damaged boat hull.