Not THAT long ago, deduced reckoning was that ONLY way to go, unless you had an RDF (which didn't really help that much). I believe mastering that skill made me a better, safer, boater today. Just like, when I was in high school, before handheld calculators, it was common to use a slide rule. Those of us who mastered it became much better at math as a result. Just for kicks, once in a while I run with just a watch and compass. Highly recommended.Dead reckoning is great if your crossing the Atlantic on the mayflower, not realistic in coastal waters, especially if your doing visual navigation.