Last week I was dogpaddling across the Little Colorado River when I realized midstream that my Garmin etrex Venture HC was in my pocket and not inside my drybag. Once on land I pulled it out and the screen was completely filled with water, I figured it was toast. But I took out the batteries, shook out the water as best I could, put it in a warm oven for several hours when I got it home, then waited a few more days. And yesterday when I put the batteries back in, it fired right up!
Props to Garmin for a pretty tough little unit!