Exploring 3D-Printed Boat Propeller Designs: Seeking Performance Upgrades
Let’s talk about something that might seem a bit dull at first glance: propeller designs. But now and then, a new design emerges in the media, claiming to improve performance and reduce noise. It sparks some excitement and curiosity. Well, if you’re like Daniel Riley from RCTestFlight, you take it a step further and 3D print a few of these propeller designs to test them out. One design that gained some attention is the toroidal propeller, which made waves in the world of flying drones. However, toroidal boat propellers also exist in commercial applications.
Daniel decided to experiment with these propeller designs, printing them in nylon using a professional printer instead of a standard home FDM printer. This ensured better surface quality without the need for additional sanding and treatment. Surprisingly, the surface treatment didn’t seem to have a significant impact on the results during further testing.
To dig deeper into the problem, Daniel conducted bubble tests. In these tests, the air is blown in front of the spinning propeller to visualize how the water flows. The bi-blade and toroidal designs showed considerable stalling in the bubble testing, which might account for the drop in performance. Daniel explored both the CAD model and a patent by Sharrow Marine, a company that claims better performance than regular boat propellers. Unfortunately, he didn’t find any obvious clues in his investigation.

It’s worth noting that the 2-blade propeller printed with an FDM printer turned out to perform the best among the designs tested. Surprisingly, the bi-blade design, which features two sets of blades positioned one after the other, performed worse but still better than the toroidal design.
So, what’s next for Daniel? Well, he aims to strike a balance between fluid dynamic modelling and the claims made in glossy marketing materials. He wants to explore how near the claimed performance levels can be attained by a person at home with a 3D printer and some free time.
It’s fascinating to see how 3D printing opens up opportunities for experimenting with different propeller designs. While some designs may not live up to the hype, others show promise. Through careful testing and exploration, we can uncover the potential for improving boat propeller performance. Who knows what other innovative designs might emerge in the future? Exciting times lie ahead in the world of propeller technology!