Are you using a mapping card? If so, take the card out and try it, see if you get the same results.
I've got a H2O that I haven't had any problems with. I'm more then happy to sell it to you. As far as trading for a HB donut unit, I wasn't aware the HB made handheld gps units? Are you comparing a fishfinder to a handheld GPS? I realize that the H2O is a legacy unit, so I'll give you a good deal on it. $25.00 + 5 shipping. My H2o is at least 4yrs old.