In the very old days, when Loran A was just coming in, we used an RDF on our charter fishing boat out of Wrightsville Bch, NC. Used it to return to fishing spots offshore and to find other boats that were on a hot spot. We would tune in a known station, vector it on the chart, find another and, voila, we were at the intersection! I didn't know they were even still around. It worked right beside our chart recorder with the graph paper on a roll and the squiggly needle!