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Without blade tips, the MX-1 is proven to be up to 15% more efficient than conventional props.

A company called Sharrow Engineering of Philadelphia has brought to market what is being hailed as the first major breakthrough in propeller technology since the 1930s.

The company, the brainchild of engineer Gregory Sharrow, was founded in 2012 to “reinvent the methodologies and technologies used for propulsion in the 21st century.” 

As you can see from the images, Sharrow has forsaken traditional solid blade design in favour of an open spiral concept. The company and those who have tested the prop say this has eliminated the most common problems with rotary propulsion such as creation of vortices and cavitation at the tips of the blades.

Unlike every prop that’s come before it, rather than blades, the MX-1 has loops of metal attached to the hub.How does this change the dynamic? In a nutshell, much of a prop’s inefficiency can be blamed on the blade tips, where vortices and cavitation (commonly  called tip vortex cavitation, or TVC) form, creating turbulence and sapping efficiency. Simply put, the loops on a Sharrow have no tips. The net result is an efficiency gain of between 9% and 15%. But just as important, eliminating the cavitation vastly reduces vibrations and noise and makes for a smoother, quieter boat ride. The downside: They’re very expensive at the moment.

In September 2019, conducted a four-day review of the of the Sharrow propeller and compared the performance to industry standard stainless-steel blades. Results from the BoatTEST review prove that the Sharrow propeller has the following advantages over traditional bladed props:

1. Performs significantly better at idle
2. Planes at a lower RPM
3. Is faster at all RPM settings
4. Gets significantly more mpg at 3000 and 3500 RPM
5. Is more fuel efficient at every speed through water setting
6. Is as much as 18% more fuel efficient at 26-28 MPH
7. Produces the highest top speed
8. Creates noticeably less vibration
9. Is generally quieter
10. Has superior handling in tight turns at high-speed
11. Improves handling in reverse
12. Provides the greatest range at all speeds

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