There seems to be three critical attributes of a propeller which can be relitively measured in size against another. These three attributes are the propeller's diameter, pitch, and aspect ratio. Propeller Diameter measures the diameter of propeller disk, or the distance between the blade tips. Pitch has to do with the angle of the propeller blades. Properly twisted propeller blades should advance through the water at a rate equal to their pitch.
Aspect ratio has to do with the ration of the blade's legnth to the blade's width.
I belive it is directly related to how much blade area is present in the propeller disk. Its blade shape was symmetrical and elliptical. When looking at the propeller from the stern, with eyesight in line with the shaft, very little of the propeller's blades were visible in relation to the disk the blade sweep. I think there was a chance the Bolly propeller could have been a more efficient blade than the Seagull. But before I begin messing with all the latter, I must make up my mind where to start with my propeller's blade aspect ratio.