Innovation in the marine industry typically moves at a slow pace. I remember when bluetooth stereos became the standard in cars, it took another 3-4 years before they really found their way into boats. When people ask me why the industry is so slow to adopt tech, I tell them about how most boat deck layouts and design are often mocked in cardboard cutouts before ever seeing digital mocks in design software like CAD. The old way of doing things has been engrained in the supply side of the industry for many years.
But that’s changed over the last 5 years or so, as people in science and tech are bringing their expertise to their favorite hobby of being on the water. As a result, we’ve seen some pretty groundbreaking products enter our space. As a boat guy and tech enthusiast, I’ve been quick to adopt innovation on my own boat. And one of my favorite innovations in all my years of boating is the Sharrow Marine propeller.
You’ve heard the saying, “let’s not reinvent the wheel here.” But that’s exactly what Sharrow has done to boating’s oldest and most unchanged element. It might sound like a fool’s errand. After all — if it ain’t broke, don’t fix it. But, the performance data and list of enhancements they claim their propeller delivered was hard to ignore. So I invested and installed a Sharrow MX on my 1999 Cobalt. And what I found was that their propeller did everything they said it would. But more impressively, there were benefits they don’t talk about that I enjoy the most in my application.
First of all, what makes the Sharrow unique is that the blades form a loop, rather than solid surface blades. The purpose of this loop design is to eliminate cavitation and blade tip vortices. As the blade of a normal prop spins, the rapid change in pressure at the tip causes vaporization as the water rapidly boils. This process limits the amount of ‘grip’ a prop maintains along its edges, while also creating a significant amount of excess sound. By looping the blades, this effect is largely eliminated. You can see the difference in underwater footage on BoatTest.com. You’ll notice the swirled bubbling around the standard prop in the bottom half of the image — bubbling that is absent around the Sharrow prop.
By eliminating this vaporization, the prop provides the boat and its operator with dramatically improved control and low and high speeds, through turns, and around the dock. It also generates a tremendously noticeable difference in the lift at the transom, which is why boats with the Sharrow propeller climb and maintain plane at much lower RPMs than boats with traditional propellers.
In my use case, I found all of this to be true. With a standard, 3 blade stainless propeller on my single prop Volvo Penta SX drive, my boat planed at 2800-2900 RPMs and maintained about 22 MPH. With the Sharrow MX, it now planes at 2200-2300 PRMs and maintains about 24 MPH at that speed. This mid range is where operators of the boat find the greatest efficiency benefits.
But where I was surprised the most was how that extra lift at the transom changed the way my boat rides. On plane, my Cobalt now sits about 3-5” higher out of the water, which means that the V of its hull has more real estate to travel through a rough chop, resulting in better ride quality. This was not a benefit I saw listed anywhere on their website at my point of purchase. But it’s one that I quickly realized is notable.
And for you speed fanatics who always ask the question, I was able to increase my top speed from 51 MPH to 53 MPH as well.
So is it worth investing in the Sharrow Propeller? I’d say it depends on what you’ve got. Where I remain skeptical is whether or not the application for counter rotating propeller drives like the Mercruiser Bravo 3 and the Volvo Penta DP is worth the upgrade. I have yet to experience what it’s like on that setup. But if you’re like me, have a single propeller outdrive, and you’re looking for better performance and control, some minor fuel savings and a much quieter and smoother ride, it certainly delivers.
