Okay here's the deal. Right now I'm still saving to get my new decked out Alumacraft later this year. In the meantime I need a means to mark structure I'm placing. I saw some GPS units at Walmart for around $120 that are Garmin units. I asked the person if it would work on water, because I don't know anything about a GPS right now. They didn't know. So do you guys have any input for a unit that is waterproof and will serve me until I get my HDS units in my new boat? Preferably under $150 since I wont have much use for it later on.