My new boat came with a Humminbird 383c depth finder with GPS. I've been out a couple times without any problems. Then tonight I am out with my daughter and the unit just shut off after about 20 minutes on the water. It powers back on and I press the Exit button to go to the next page.  Then it shuts off again. This cycle keeps repeating itself until I finally give up and just shut it off. I tried removing the unit from the base thinking it might reset itself. No luck. At this point I am ticked off.  Anyone else with humminbird have this problem?