i've used the rolling plotter. It's a substitute for parallel rules and I find them both deficient. Particularly on a small boat, one must keep a degree of downward pressure for either to track accurately, and that is not always practicable. For the roller, you must push it evenly from the center, as well as have your chart well secured. I still prefer traingles due to size and flexibility of use. Never did much care for parallel rules except for running a long dr track.
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.