Patrick, if you had a
handheld compass (and a reasonable sense of its variation and deviation in your cockpit) and a chart, you could obtain two LOPs to determine distance offshore in clear weather, or if you have a watch and a steady hand on the tiller, you can use a simple formula to determine boat speed, distance off, etc.
It's the chart that gives you the land feature indicating general location. If you don't actually KNOW the land feature, and think it might be one of two or three features (
radio towers look alike), you can determine which one it is via bearings, height via sextant, and so on.
A short coastal pilotage course (combined with a lot of chart work and sailing courses parallel to the shore) taught me more about navigation than years of dicking around with GPSes. Now I'm the guy who says "steer 195 degrees magnetic" BEFORE the
GPS goes on. In fact, I ask guys for whom I crew to keep the
GPS off until I've provided a course.
If you learn this stuff, you can detect currents, set and drift, all transitory aspects of the watery environment easy to overlook with GPS.