I have been looking through this post and wanted to add my experience. I just went on an 8-day river rafting trip on the Colorado River through the Grand Canyon. I marked about 20 different spots for virtuals but my GPSr (Garmin E-Trex Venture) got water on it from being hit by 15 foot waves in the rapids. The screen fogged up and eventually quit working altogether. I am SO upset. Needless to say, I will be buying a see-through dry bag of some sort for future expeditions.