Most of our fly fishing is on lakes. Our lakes have sharp drop offs and fish run along these breaks. The depth finder sure beats a sounding cord and weight to find these breaks.

I am currently using a Hummingbird 768C w/external GPS. Love it! We troll flies for trout from September until freeze-up and the track features is useful for covering productive water. We mark a waypoint every time we get a fish and before long you have a pretty good picture where the bulk of he fish are hanging out. It shows both track and depth / bottom contour. The GPS has also been useful in finding the ramp when night and fog set in at the same time and you loose all sight of the shore. An 800 acer lake might as well be 8000.

I had a Hummingbird before I installed the 768 that only showed depth. Used it for several years. It has now found a home on my sons boat so it is still going.

I have a Garmin on my Hobie Float Cat that shows depth and water temperature.

Jerry