Sharrow’s unique design results in propellers that are more responsive and quieter.
There are few companies that produce a product or service that truly innovates in the realm of recreational boating. To be fair, powerboating is a mature activity, almost 200 years old. By now, it’s mostly about evolution, not revolution. So, awarding a Marine Power Innovation Award is not done lightly.
But Sharrow Marine Propellers impressed us.
By now, you may be familiar with the odd-looking propellers that look like their blades have been hollowed out, and the tips folded and rounded to nubs. These would be the MX propellers from Sharrow Marine, a Michigan-based company that claims this innovative design improves your boat’s efficiency, handling and noise output. To verify these claims, we decided to pit a pair of Sharrow MX3 propellers against comparable-size traditional stainless-steel propellers. Here’s what we found.
On test day, we ran our typical data on a Robalo R302 center-console powered by twin Yamaha F300 outboards. First, we ran the numbers with traditional three-blade 15-by-19-inch stainless-steel propellers. Then we went back to the dock and swapped them out for 15-by-19-inch three-blade stainless-steel Sharrow MX3 propellers. Running both sets of props with an identical fuel load and crew weight, we found that the Sharrow props helped the Robalo plane about a second faster than the traditional ones, and it hit 30 mph about a half-second quicker.
Just by looking at the performance numbers, you can see that the Sharrow MX3 props shined at 3,000 rpm. With the Sharrows, we could easily attain a cruising speed of 27.1 mph while recording noise levels of 80 dB(A) at the helm. With the traditional props, we struggled to stay on plane while recording a speed of 14.3 mph and an 85 dB(A) reading.
What the numbers don’t show is how well-connected to the water I felt while handling the boat at the helm, from idle speed to top-end. The boat felt much smoother climbing onto plane and didn’t slip or cavitate during hard-over turns at 30 mph. The boat also felt more responsive at the dock, comparable to the difference between a sterndrive with dual contra-rotating propellers and a single prop.
Sharrow achieved this through the blade design, essentially eliminating the vortices that swirl off the blade tips of traditional props and lead to drag, cavitation and increased vibration. There’s a more complex scientific explanation, but the gist of it is that when you replace your regular props with Sharrows, you will notice the difference.
The Sharrow Propeller™ was invented by Gregory Sharrow in 2012 and is the first major advancement in propeller technology since the 1830s. Its design has solved the most basic problem of rotary propulsion. Specifically, tip cavitation and vortices have been eliminated or significantly reduced, offering incredible performance gains over traditional propellers.
More than 100 U.S. and international patent applications have been filed with the U.S. Patent and Trademark Office (USPTO) and foreign countries to protect the intellectual property rights for the Sharrow Propeller™. Already, 78 patents have been awarded in the U.S., Australia, Canada, Chile, China, Europe (14 countries), Japan, Mexico, New Zealand, Philippines, South Korea, Singapore, South Africa, Russia and Taiwan – with many other patent applications pending in countries around the globe.
About Sharrow Marine & Sharrow Engineering
Sharrow Engineering, LLC, is a nautical and aeronautical engineering company dedicated to the research and development of revolutionary high-performance propulsion technologies for the maritime and aeronautical industries. Sharrow Engineering is the parent company for Sharrow Marine, LLC, and Sharrow Commercial Marine, LLC. Company offices are headquartered in Detroit, MI. Sharrow Engineering, LLC, has assembled a team of the world’s top aeronautical, nautical, aerospace, and mechanical engineers to assist with the company’s core mission to reinvent the methodologies and technologies used for propulsion in the 21st century.
REVOLUTIONARY EFFICIENCY
Independent, third-party testing led by the University of Michigan’s Marine Hydrodynamic Laboratory demonstrates the Sharrow Propeller is 9-15% more efficient than the industry standard Wageningen B-series screw. Efficiency gains of this magnitude are a game changer for the global propeller industry where 1% is considered substantial.
Sharrow Engineering funded the development of an enhanced 12-stream dye injection visualization system with high-speed 750 fps camera at the University of Michigan’s Marine Hydrodynamics Laboratory.
As the video shows, the larger volume of the captured stream of the Sharrow Propeller™ and greater downstream mixing. Note in the photo the outer orange streamline that is ingested into the Sharrow Propeller™ passes beyond the tip of the standard propeller. The standard propeller produces a concentrated tip vortex while the Sharrow Propeller™ has no tip vortex; the tip vortex is an induced loss and a source of cavitation.
Here we see underwater video captured on a test vessel which demonstrates one of the greatest strengths of the Sharrow Propeller™. The standard propeller shows tip vortices cavitation (TVC), which coalesces into the typical helical paths from each blade. This phenomenon is expected from a standard blade and a source of energy loss. At this operational point, the speed of advance is low, and the loading is high, so TVC is very likely. Notice that the Sharrow Propeller™ (on the top) doesn’t show any TVC, which is one of the many reasons the Sharrow Propeller™ is more efficient than a standard blade.
The noise reduction that you will experience on your boat with a Sharrow MX™ is incredible. Cavitation created by standard propellers is a huge source of noise for boaters. The Sharrow MX™ dramatically reduces traditional tip vortices and cavitation, providing you with a smooth and quiet ride like you’ve never experienced before.
True Advance™ is a design feature within all Sharrow Propellers™ that contributes to the incredible efficiency and performance of the Sharrow Propeller™. It allows our propellers to achieve their maximum advance rate and efficiency much earlier on in the RPM and speed range of a boat compared to standard propellers. The benefits of Sharrow True Advance™ include:
- Unmatched Efficiency
- Greater Range
- Superior Fuel Economy
- Increased Load Capacities
- Faster Speeds (up to 10 MPH FASTER) at Cruising RPM’s
- Enhanced Handling and Maneuvering
- Up to 50% More Reverse Thrust for Greater Stopping Power
- Lower Emissions / Reduced Carbon Footprint
- Quieter Operation
- Less Driver and Passenger Fatigue
- Longer Engine Life
- Can be Utilized on Virtually any Propeller Driven Craft
- Each Sharrow Propeller can be Custom Tuned to Each Specific Application
An analysis of a boat’s performance data reveals that the actual traditional propeller “slip” is significantly more than expected at cruising speeds, while the Sharrow propeller achieves dramatically higher efficiency percentages much earlier on the boat’s total operating range.
Sharrow’s True Advance™ Delivers 97+% of maximum efficiency as soon as the boat reaches planing speed
In this example, the conventional propellers don’t reach 97% of maximum efficiency until nearly full speed
Greater efficiency means increased fuel economy, increased range, fewer fill-ups, lower emissions and quieter operation
Sharrow’s True Advance™ design delivers higher advance rates earlier in the operating range when compared to conventional propeller designs, delivering superior performance, enhanced control and a safer overall boating experience.