1648 Jon Boat?... Did Columbus sail on that bad boy or what?
Kidding.
I just got a 1953 Alumcraft, and am in the same process of cleaning... I took several sized wire brushes to the hull and cleaned it that way... time consuming, but really gets into the cracks and crevices. Really reveals the nicks and dings in the bottom too... also kind of smooths out the gouges in the bottom.
From there I took an orbital sander and hit it a few times... am not sure if I plan on giving it a real good shine or not...
I took some dish soap and water and scrubbed it down with a brillo pad and it left a good clean look to it.
Some have recommeneded TSP, which I bought, but have not used it yet... plan to use that on the inside since I have non skid bottom.
Just my 2 cents