I had a handheld GPS that died a few years ago so I got the Navionics App on my phone. I now have a Toshiba Android tablet and use the Navionics App on it. I have a rubber case for it that protects from shock but not water. This past weekend was really wet so I slipped it in a heavy duty Ziploc brand bag and had no problems using it in the rain. I don't think I'd go swimming with it like that but I felt comfortable with it in the cockpit in a constant rain. As you mentioned Eddie, the track line is a great feature for close in navigation. Further out I just pick a waypoint and get the bearing and range information.

Is your GPS the Magellan NAV 1000? You can still buy them on eBay!