I'm looking for recommendations for a handheld GPS that has mapping capabilities. For a point of reference, I sail on Lake Champlain, so I'm looking to mark local hazards to navigation, regular routes, favorite anchorages, an anchor alarm and so on. I sail most weekends from May to October (with some overnights), as well as sailing until dark at least one night a week after work. If it helps, I sail an O'Day 23.Thanks!