A quick search out on the internets reveals... no factual data. Many sources speculate, but none have documentation to back it up. It seems the reel was invented so long ago that no documentation survived if it existed. The crank on the right to avoid clothing seems logical. They were also used for trolling so, when sitting in a rod holder the "winch handle" on the right would make sense. Most fishing gear was designed for commercial use first. I use the right handed reel so I could switch hands to defer some fatigue. FWIW.