Mercury Racing’s quad-overhead cam, twin-turbocharged 1350 engine has completely changed the high-performance powerboat engine game. Even the Fond Du Lac, Wis., engine builder’s toughest competitors, from Mike D’Anniballe at Sterling Performance to Tommy Hofstetter at Chief Engines, won’t argue that point. Listed at a jaw-dropping $203,000 with an M8 drive developed specifically for the power, the 1,350-hp engine has been among the company’s most successful releases. That it was released in the midst of the toughest economy since the Great Depression speaks volumes on the unrivaled quality of the product.

Skater catamaran

Without props that could handle big torque and big horsepower, boats such as this exotic Skater catamaran couldn't put the power from the Mercury Racing 1350 and 1100 engines to the water.

And yet, without Mercury Racing’s CNC Cleaver propellers -- manufactured to handle that kind of power, and even more notably the associated matching 1,350 foot-pounds of torque—the 1350 wouldn’t go anywhere, so to speak. Because no matter how pretty and sophisticated a marine engine is, no matter how well-dressed it is in carbon fiber bling, it’s pretty much useless without a prop that can put its power to the water without falling to pieces.

For correct applications and warranty issues, Mercury Racing offers its five- and six-blade CNC Cleaver propellers, all of which come standard with a gleaming Pro Finish, in versions rated for 600-, 900-, 1,200-, and 1,500-hp engine applications. Priced at $5,800 apiece for the five-blade models and $6,800 apiece for their six-blade siblings, the 14-1/2- to 18-inch-diameter props in pitch sizes (the theoretical distance a propeller can move a boat forward in a single rotation) from 26 to 42 inches. Rake angles of 15, 18, and 21 degrees are offered for various applications, though 15- and 18-degree wheels are the most popular choices.

Cleaver 6-blade

The 5- and 6-blade Cleaver props are cast, not forged.

But unlike the big-power propellers from Mercury Racing’s only significant competitor, Hering Propellers in Marysville, Wash., its five- and six-blade CNC Cleaver wheels are cast rather than forged. At least some of the reason, though far from all of it according to Mercury Racing’s resident propeller expert Scott Reichow, is economic.

“Forged propellers cost twice as much money [as cast propellers] but aren’t necessarily stronger,” he explained. “We have not had any failures when the correct prop is matched to the correct horsepower application.”

Why would anyone want to stray from those horsepower-specific propeller-application ratings? Simple—the higher a CNC Cleaver propeller’s horsepower rating, the thicker its blades are. Generally speaking, thinner blades go through the water more easily, which can translate to quicker acceleration and higher top speed.

“Of course, we don’t recommend it at Mercury Racing, and its voids the propeller’s warranty, but by sending a smaller wedge through water, the prop spools up and accelerates quicker, and can be faster at the top. But again, we don’t recommend this.”

Mostly science with a dash of art, the key to the performance of the CNC Cleaver line is CNC-machine finishing. While Reichow and Rick Mackie, Mercury Racing’s director of marketing, won’t say anything specific about the company’s CNC process, both explain that “zero balance” is among the goals for and key attributes for performance and reliablity of all the company’s CNC Cleaver propellers.

“Zero balance is a term we use that means the propeller is perfectly balanced,” said Reichow. “If one blade is heavier than another, that can create propeller vibration. By checking the balance of each propeller on a balancing rod, we can balance the prop and minimize any vibration by taking off materials in certain locations.”

After the CNC process for each propeller is complete, a Mercury Racing propeller technician checks it for cosmetic quality,  removing machine marks and touching it up if necessary. The finished products are then boxed and shipped. Like for the 1350 and 1100, demand for the CNC Cleaver props has been strong.

Mackie pointed out that the propellers actually were developed in conjunction with the 1350 and M8 drive as part of an integrated product, rather than as separate products.

“It was all designed and built to handle the package,” said Mackie. “At Mercury Racing, we don’t just build an engine or a drive or a propeller. We offer a complete propulsion package, from the pulley [on the engine] to the prop nut.”

Need to find a new propeller for your boat? Visit the Propeller Finder in the Gear & Parts Store.

- Matt Trulio