This raises the bar from a hand-held unit but I broke down and picked up a Lowrance LMS-520 gps graph last year as they closed them out. Adding the Navionics maps you have a unit that shows detailed views of the lake. I have had a chance on the big lakes this summer to use them exploring some ledges and it works pretty well. Not 100% accurate but I can find and hold in decent postion on the ledges using the maps. No doubt the such a unit will also help find your way if need be. With the unit and the navionics map I dropped about $500...

kc