This version helps solve some of the issues I was having with the original. it now rotates a little more freely and I increased the tolerance to make it more forgiving. This version requires a .4 nozzle and .2mm layer height or it might not work. I also would not recommend scaling or using materials with high layer adhesion as my version relies on what is basically a support interface between the propeller shaft and hull. Cooling is a must and if the propeller refuses to rotate you can pry the little slit where the propeller shaft enters the hull.
The author remixed this model.
I made the propeller thick with more of a slope so the sub will move in the water. In addition modified the contact point where the parts rub together. Instead of an angled shaft that presses against the sides causing a lot of friction the surfaces are flat and printed like a support.