PROPS FOR INNOVATION
Sharrow MX3 propellers live up to most of the company’s performance-improvement claims.
By now you’ve likely seen the funky-looking Sharrow propellers and heard they’re up to ve times more expensive than traditional props. So, when Sharrow Marine came to us with claims that its propellers are worth it due to improved speed, eciency, handling and overall feel, we had only one recourse: Pit the MX3s head-to-head versus comparablesize traditional stainless-steel propellers. What did we nd? e results backed the company’s assertions, with the exception of top speed. Before getting into the nitty-gritty, it’s important to note the design differences between Sharrow propellers and typical outboard props. Greg Sharrow, the company’s founder, comes from a music background. e story goes that while trying to gure out how to make drones quieter to shoot video of orchestra concerts, he found that a lot of the noise he could not reduce came from vibration and turbulence caused by the blade tips. He redesigned the propeller blade so that it circles back on itself, eliminating the tip. Doing so eliminated the vortex that forms at the tip of a traditional propeller, reducing cavitation and vibration. In 2012, Sharrow applied his now-patented design to marine propellers, culminating with the new MX3.
We tested Sharrow Marine’s MX3 propellers aboard a Robalo R302 center-console powered by twin Yamaha F300 outboards. First, we ran the boat through our standard testing procedures with a pair of 15-by-19inch stainless-steel three-blade propellers. en we swapped them out for a pair of Sharrow MX3 props and ran the same tests in the same conditions.
Head-to-head, the R302 climbed onto plane in 4.7 seconds with the Sharrow props, compared to 5.3 seconds with the regular props. e zero-to-30 mph acceleration time was about a half-second faster with the Sharrows, and top speed was nearly identical; the boat topped 52 mph at 5,750 rpm with both sets of props, and max fuel burn for both was 52.7 gph.
Our test showed that the Sharrows shined at cruisingspeed eciency. At 3,000 rpm, they delivered 27.1 mph, burning 15.7 gph for a 1.7 mpg. With traditional propellers, the R302 struggled to climb onto plane at 3,000 rpm, achieving 14.3 mph and burning 14.2 gph for a 1 mpg range. at’s a big leap in eciency. e noise difference was noticeable; we recorded 80 dB(A) at 3,000 rpm with the Sharrows compared to 85 dB(A) at 3,000 rpm with the traditional propellers. e traditional propellers did not hit comparable speeds until 3,700 rpm, burning 21 gph to hit 25 mph for about 1.2 mpg.
At 4,000 rpm, the Sharrows delivered a top speed of 38.2 mph, burning 25.7 gph for a 1.5 mpg rate and an 83 dB(A) reading. e traditional props went to 33.3 mph, burning 23.9 gph for a 1.4 mpg rate and an 88 dB(A) reading. For a full review of the performance data, scan the tag on this page.
What the numbers don’t tell you is how the boat feels at the helm. In close-quarters handling at the boat ramp and the fuel dock, the R302 with the Sharrow MX3 props felt more responsive to throttle and wheel adjustments. e transition from idle speed to planing speed felt much smoother. Turning the wheel lock-to-lock at 30 mph, I felt no slippage or cavitation as the boat turned. I also noted that I did not need to rev the throttle to maintain speed while executing turns as you would with traditional propellers. And at top speed, the boat felt more connected to the water with the Sharrow MX3s.
Because many people spend most of their time cruising, I’d say the MX3 propellers live up to Sharrow’s claims of improved speed, eciency, handling and noise reduction. at is why we gave Sharrow a Marine Power Innovation Award in 2022.