The former head of Mercury Racing who left the Fond du Lac, Wis., company in 2013 with products from Zero Effort controls to the Quad Cam Four Valve (QC4v) turbocharged engine series launched during his more-than-20-year tenure, Fred Kiekhaefer has been granted an engineering patent on a “Marine Surface Propulsion Device.” The patent for Kiekhaefer’s creation, which is designed for high-performance V-bottoms and catamarans, came through on Dec. 26, 2017.

Kiekhaefer’s prototype propulsion unit has been installed in a diesel-engine-powered 39-foot V-bottom (click image to enlarge).

“It’s a surface drive with an infinitely variable pitch propeller,” said Kiekhaefer, who moved to Colorado after departing Mercury Racing and set up his own design and engineering shop he calls K.Lab Design Works. “The propeller blades can go from almost completely feathered to paddle-wheeled. You can change the pitch from very low as you’re coming on plane, increase the pitch when you want to go faster and increase it even more when you want to go really fast.”

Kiekhaefer hasn’t officially named the product, but his first propulsion unit has been installed on the transom of a 39-foot V-bottom powered by a single 550-hp Cummins diesel engine by famed South Florida-based rigger John Pompi. If all goes to plan, on-water testing should begin in two to three weeks. Although he designed the drive to be paired with gasoline-fueled high-performance marine engines, Kiekhaefer is initially testing in a diesel engine application because of the diesel’s narrow engine-speed range. A drive with a variable-pitch propeller would eliminate the need for solutions such as multi-speed transmissions in marine diesel applications.

“Most marine diesel engines top out at 3,000 to 3,200 rpm compared to 6,800 to 7,000 rpm for a gasoline engine,” he said. “I knew I needed to start with diesel, where everybody struggles with the load curve and getting up on plane.”

Kiekhaefer will manually control propeller pitch changes in the early testing of the propulsion unit. But the final consumer version of the product will be completely automatic—with manual override, of course. That means, for example, if an operator hammers the throttles the propeller will adjust pitch for maximum torque and then continually adjust for optimal acceleration. When the operator backs off the throttles, the propeller pitch will change again to maximize efficiency.

“That’s where the algorithms get really fun,” Kiekhaefer said, then laughed.

Kiekhaefer currently is building the second prototype unit. The one installed in the V-bottom was built with right-hand propeller rotation. The second product will have left-hand rotation.

For a closer look at the first page of Kiekhaefer’s engineering patent, click the image above.

“I have been working on it for four-and-a-half years,” he said. “The first year, I had to teach myself CAD (computer-aided design) so I bought CAD station and started leaning. The last time I did any real engineering, I was still using pencils and Mylar.”

Editor’s Note: Look for a complete feature on Kiekhaefer’s project in the January/February issue of Speed On The Water digital magazine.

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