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Innovation in marine propulsion has taken a step forward recently with advancements in materials and design, such as the new Sharrow Propeller. Claiming to be the first major advancement in the sector since 1830, the creators state that this unique new propeller eliminates and significantly reduces tip cavitation and vortices.

In this latest article, we thought we would take a closer look at what exactly the Sharrow Propeller is, the technical advancements behind it, and some of the benefits that it can provide.

What is the Sharrow Propeller?

Developed by Sharrow Engineering, the Sharrow Propeller has a unique design that is considerably different from traditional propellers. Instead of the classic straight blades, the Sharrow consists of multiple blades that extend radially outward from the hub to form a loop. Each of these loops contains an intake portion, an exhaust portion, and a top portion.

The design is an advancement on the Toroidal Propeller, with the engineering team utilising their knowledge of fluid dynamics to address previous issues with propulsion. It was these advancements that saw the Sharrow Propeller one of Time Magazine’s best inventions of 2023.

While each of these loops can be split into three sections (intake, tip, and exhaust), they work in tandem with the others. This creates more thrust by increasing the amount of water between the intake and exhaust, while the loop helps to decrease tip vortices. In addition to improving performance, this design also reduces noise at cruising speed.

Diagram showing the intake, tip and exhaust portions of the Sharrow propeller loops.

How is the Sharrow Propeller an improvement over traditional designs?

The team at Sharrow Engineering claim that the Sharrow Propeller offers a range of performance gains over traditional propellers, with the product undergoing rigorous third-party testing at the University of Michigan’s Marine Hydrodynamic Laboratory.

Some of the biggest advantages of this unique propeller include:

Increased performance
Independent and verified studies have found that the Sharrow Propeller was able to increase performance. This was found to be a significant improvement at idling speeds but also faster at all RPM settings. When installed, testers found that the Sharrow device also increased top speed, allowing boats to travel faster with the same power output.

Better fuel efficiency
Alongside increasing overall performance, the Sharrow Propeller has also been shown to help reduce fuel consumption. A study by BoatTEST found that the boat was more efficient at every speed through the water setting, but they were enjoying significantly better MPG at 3,000 and 3,500 rpm, while when kept at speeds of 26-28 mph, the boat was as much as 18% more fuel efficient.

Improved handling
Of course, it’s not just about speed and fuel efficiency. The Sharrow Propeller has also been shown to offer better handling in tight turns at high speeds and while in reverse, while Sharrow Engineering claim that their prop is able to offer up to 50% more reverse thrust, allowing for greater stopping power.

Quieter performance
Finally, another benefit of the Sharrow Propeller is that it is considerably quieter when in use compared to traditional alternatives. This makes for a more pleasant experience for drivers and passengers alike.

Underwater video comparing a standard propeller design with a Sharrow. The Sharrow does not show Tip vortex cavitation (TVC), a substantial advantage. Video credit: Sharrow Marine

Are there any downsides?

While there is a huge number of claimed benefits for the Sharrow Propeller, the device is not without its downsides. The primary issue is that the majority of the studies and resources online have focused on outboards, and it remains to be seen whether it would provide the same level of performance on larger inboard propelled vessels.

Another significant downside currently is the overall cost. Because they are new to the market, the costs are higher than for more traditional blades, as they are not only limited in number but also require more specialist construction techniques. As they are so new, there is still an unknown quantity on how they will perform in terms of durability and performance over the long term.

Are Sharrow Propellers repairable?

One significant disadvantage of the Sharrow Propeller is the uncertainty of repair, potential cost of repairs and time taken to repair due to their unique design and construction. To overcome this, Sharrow has implemented the Sharrow Care Protection Plan which is designed to cover damage that occurs from normal operational use.

Coating the Sharrow Propeller with PropOne

While the Sharrow Propeller offers a range of performance benefits, like all propellers, marine growth can have a significant impact on performance. It will be interesting to see how fouling might impact the efficiency of this unique design when compared to the more traditional propeller design.

While we have not been able to test the new Sharrow Propeller with our PropOne foul release coating, we do expect that preparation and application will be slightly more challenging due to the looped design of the prop. That unique design creates an unconventional water flow and movement through the propeller, which could make fouling easier to be released. We await to see if the Sharrow prop will be commercialised for the inboard market.

Fouling growth can impact any propeller, though, so if you want to ensure your prop is protected, make sure you coat yours with PropOne.