I needed to reprint the bearing holders several times with slight variations in offset to align the shafts and get the right tension on the belts.   This is much easier than reprinting the pulleys.   The shafts need slight angles (1 or 2 degrees) to compensate for the tension of the belt and to ensure the belts walk the right direction.  This also determines if the intermediate shaft is pulled in or out and I wanted to get it well balanced to avoid axial loads on the ceramic bearings.

The motor draws 15 watts (friction losses) spinning the propeller in air at full speed.  Speed in the water is only .75 knots because pulley slips on shaft.  This is using about 65 watts.   It is impossible to use a keyed shaft on a plastic pulley, the plastic stretches.