Sharrow Props Big Improvement on a Tri-Toon w/Mercury 350
Case History #2 by Alistiar Temps
Whenever we reach out to boat owners running Sharrow propellers, they often highlight the increased fuel efficiency or extended range that they get from them, but in Niels Mossbeck’s case, it was all about the handling.
Niels was an early adopter of the Sharrow prop. With a background in industrial R&D for many years, the novel geometry interested him as soon as he read about it in an early review in Boattest.
“When you see something that is really new, and which just makes sense, you want to try it,” he explained. He began inquiring about the new propeller immediately, and finally got his hands on one in the summer of 2022.
Although he is based in Florida, Niels wanted the Sharrow prop for a pontoon boat at his summer house on Table Rock Lake in Missouri, a 2017 25-foot Harris Grand Mariner tri-toon with a single Mercury 350, which provides plenty of power to tow kids and grandkids, or to spend the day out on the water with a boat full of friends and family.
A Mercury 350-hp engine on a 25 Harris Grand Mariner were both enhanced with a Sharrow prop.
A Pontoon Boat ‘wants to go straight’
Although he was pleased with the comfort and convenience of the Grand Mariner, there was one aspect that he did not like as much: “One thing about a tri-toon boat is that you are on three straight, parallel tubes: that boat wants to go straight,” Niels explained.
“In that regard, it is much more difficult to handle than a regular runabout boat, which can maneuver more easily, whereas a pontoon boat wants to go straight,” he added. The boat’s handling in tight spaces when docking was challenging, and it demanded a big radius to make turns.
Makes Docking Easier
Thus, the aspect that Niels found most intriguing about the Sharrow propeller was the prospect of improved handling: “If we can get better handling, for instance in the marina, and we can make sharper turns, it will make the boat much more useful,” he told himself.
He wanted to make the boat easier to steer and more enjoyable, especially for his wife Sheri, who also loves operating the boat, taking out their grandkids for a day on the water.
After a full boating season since the Sharrow prop was delivered in June 2022, Niels can now say that “it has delivered” on the handling front. “We are very pleased with how it handles. Now, it can pretty much turn on a dime.”
Like driving on snow with winter tires
The improvement from the Sharrow props was especially noticeable on the powerful 350 Mercury engine, providing better traction out on the water. Niels, who is Danish, provided a wintery analogy: “If you have ever driven on snow, I would compare the standard prop to a summer tire, whereas the Sharrow prop is like driving on snow with winter tires. Your steering is so much better and your traction is so much better.”
‘Pretty cool’ Gas Savings of 30 Percent
One clear advantage of the Sharrow propeller, Niels told us, is that now the boat comes up on plane “from 500 to almost 700 RPM before the stock propeller, and he estimated that this had improved his fuel efficiency by 30 or so .
While he wasn’t sure if these fuel savings would suffice to cover the cost of the propeller, Niels pointed out that with gas prices on the marina ranging from $5 to $6 per gallon, reducing the gas bill by a third “is still pretty cool!” He also pointed out that for anyone concerned about the environment, burning 30 percent less fuel was a net positive.
The Single vs. Twins Dilemma
Generally, people buy tri-toons because they want to go fast, be involved with towing sports, and/or carry a particularly heavy load of people. Then the question begs, should they buy twin 250s or 300s, or a single 350. Because of the doubling of conventional blade area and increased horsepower with twin engines, this tri-toon could possibly achieve speeds as high as to the low 50s, depending on load.
Since standard SS props cost from $850 to over $1,000, the incremental cost of a Sharrow prop is really more like $4,000 to $4200, not $5,000
The second engine, depending on horsepower, will cost $26-$30k. Typically, the toons we test this size with twin engines will top out in the low 50s. So, to go 4-7 mph faster than the boat will run with a single engine, is it more reasonable to buy a single 350 and equip it with a Sharrow prop?
Boat Owner’s Own Test Numbers
It is not often that we run test numbers that we have not taken or verified, but since Niels went to the trouble to do an A-B test, we will publish them. We couldn’t think of a better judge of performance than the person who owns the boat.
As for performance, Niels ran his own tests and found that at every RPM above idle , the Sharrow produced better MPH results per RPM than the Mercury’s standard Enertia propeller across the board. The Enertia series prop is generally considered by the industry as one of the better props on the market.
Another benefit was noise reduction: “We have less noise, less vibration with the Sharrow prop than with the standard Mercury prop, so you can go down the lake at 25, 30 MPH and have a regular conversation without having to yell at each other,” Niels explained. “There’s very little noise, it’s very pleasant.”
