Dead reckoning is great if your crossing the Atlantic on the mayflower, not realistic in coastal waters, especially if your doing visual navigation.
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.