Garmin 741sx help
I've been fishing with a friend fairly often. He has a Garmin 741sx. He (and I) would like to eliminate the top portion of the water column when looking at the bottom. The machine is always reading from zero to the bottom. We have looked at what we consider all the settings and cannot eliminate the top of the column. Say we are in 70' of water and need to only look at 50' to 70' How do we eliminate the top 50'. We have tried zoom, and it just zooms in on the entire column but the depth still shows 0 to the bottom. We looked at "settings" with no obvious help and have tried to drag the top line down,(touch screen) without success. I've scoured the on line manuals and still cannot figure this out. Basically, how do I set a top limit, if possible? I know it's possible on my Lowrance and Simrad, and on other boats that I fish on with Raymarine, and Furuno machines. I cannot imagine this is not possible with Garmin.