Expanded MAX5 Propeller Offerings

Mercury Racing Propeller Manager Scott Reichow and Propeller Specialist and  Project Manager Nick Petersen  review  our expanded MAX5 propeller offerings.

New 15.25-inch-diameter MAX5 models offer 3-4 percent reduction in slip compared to the 15.00-inch models on select outboard and sterndrive applications that benefit from elevated transom heights.

The Mercury Racing MAX5 propeller, developed and handcrafted by Mercury Racing Propeller artisans, is designed for single- and multiple-engine applications, including the 400R outboard and the 600 SCi sterndrive. The Lab Finished MAX5 provides a measurable reduction in propeller slip (up to 12 percent). In fact, the MAX5 prop is so efficient builders are finding they can run it higher to take full advantage of engines fitted with the race-proven Sport Master gearcase.

Bigger is Better

New 15.25-inch-diameter MAX5 models offer 3-4 percent reduction in slip compared to the 15.00-inch models on select outboard and sterndrive applications that benefit from elevated transom heights. Half-inch pitch offerings enable engines to be dialed-in to their maximum rpm operating range for enhanced throttle response, optimized cruise fuel efficiency and optimal top speed.

MAX5 ST

The shortened exhaust barrel enhances the performance of single-engine bass boats and twin-engine catamarans by keeping the stern planted for a confidence-inspired ride, while the large 15.25-inch-diameter prop stays hooked up at extreme engine heights.

The new Mercury Racing MAX5 ST propeller is designed for the 4.6L V8 300R FourStroke outboard with Sport Master gearcase. The shortened exhaust barrel enhances the performance of single-engine bass boats and twin-engine catamarans by keeping the stern planted for a confidence-inspired ride, while the large 15.25-inch-diameter prop stays hooked up at extreme engine heights.

Initial test results are promising. A 300R FourStroke spinning a 31-inch pitch MAX5 ST prop powered a tournament-loaded Bullet 21 XRS bass boat to 97.5 mph with a mere 7 percent slip!

A 300R FourStroke spinning a 31-inch pitch MAX5 ST powered this tournament-loaded Bullet 21 XRS bass boat to 97.5 mph with a mere 7 percent slip!

All MAX5 propellers feature the Mercury-patented Performance Vent System® (PVS), which enables the user to fine-tune the amount of venting needed for quick planing.

 

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Racing Wide Open in Miami

The new 1100 Competition engine was developed exclusively for the new APBA Offshore Championship series, a joint venture between Powerboat P1 and the Offshore Powerboat Association. Photo credit: Pete Boden

Mercury Racing is revved up for another big Miami International Boat Show with the release of exciting new products and revised positioning of our iconic brand.

Exclusive Power  

The all-new 1100 Competition engine was an instant crowd pleaser upon its unveiling this morning in the Mercury booth. Developed exclusively for the newly formed APBA Offshore Championship series, the 9.0-liter engine features Mercury Racing’s exclusive aluminum four-valve cylinder heads and dual overhead camshaft valve train. Read more

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Project 1080: Smooth Operator

 

Stu runs Project 1080 Wide Open at the FPC Winter Poker Run in the Florida Keys.

Florida Powerboat Club founder Stu Jones is ecstatic with the results of Project 1080 – the restoration and re-power of an epic Cigarette 38 Top Gun powered by twin Mercury Racing 540 sterndrive engine packages. 

The classic hull is updated from helm to stern with modern hardware. Mechanical throttle and shift cables were replaced with Digital Throttle and Shift (DTS). The digital cables transmit real-time data from the engines to the helm and is then displayed on the Mercury VesselView 703 touchscreen monitor. The Mercury Racing Digital Zero Effort Control transmits data back to the 540 sterndrives – signaling driver intent with effortless shifting and instant throttle response. 

Project 1080 is the official pace boat of the Florida Powerboat Club.

Stu is now focused on dialing in props. He is starting with a selection of Mercury Racing Bravo I props. He will follow up with our performance propeller specialists, Scott Reichow and Nick Petersen, to ensure he gets maximum performance for the boat’s primary application as FPC’s official pace boat. Stu loads the boat with performance-boating enthusiasts who get to enjoy a first-hand experience of the best poker runs on the water.

Look for follow-up Project 1080 posts regarding props as well as the fit and function of K-Plane trim tabs

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Prop School – Part 5: Blade Efficiency

For this, the fifth installment of my Prop School series I will review the various propeller blade designs and how they – along with rotation – affect propeller efficiency and overall boat performance.

Rotation. Propellers come in both right and left-hand rotation. Standard rotation for both outboards and sterndrives is right-hand: the prop spins clockwise when in forward gear.  Left-hand props spin counter clockwise.  Left-hand props are typically used with multi-engine applications. The counter-rotation prop works to balance (or reduce) the torque effects from the right-hand prop. Most twin engine applications are setup with the props “turning in”; the port engine spinning right-hand and the starboard engine spinning counter clockwise.

Hull types and designs respond differently to prop rotations. Some need additional stern lift to reach maximum efficiency and performance. To obtain this, the rotation of both propellers is set up, so they rotate away from each other. We call this turning the props out.  The left-hand rotation prop is on the port side and the right-hand rotation is on the starboard side.

For example, a high-speed catamaran loaded with gear and passengers often runs best with 5-blade cleaver props with 15-degree rake. Turning the props in pulls the stern down, enabling the boat to float over chop. With lighter loads and ideal conditions, the same cat can gain 6 to 8 mph when using 18-degree rake, 5 blade cleavers “turned-out.”

Performance combo pack. Racing’s 4-blade Bravo I FS and Pro Max propellers.

Number of Blades

In theory, two blade props are most efficient since they have the least amount of surface dragging through the water.  Two blade props are commonly used on lower horsepower outboards and trolling motors. Three -blade and four-blade props are the most common designs used today. The added blades reduce vibration while maintaining most of the efficiency of a two-blade design at a convenient size and reasonable cost.

The Pro Finish 5-Blade CNC Sterndrive Cleaver propeller.

Racers and performance boaters raise sterndrive mounting heights (x-dimensions) on ventilated, stepped hulls. The steps create air bubbles, raising the hull off the water on a drag-reducing cushion. This, combined with reduced drag from the higher drive heights, improves hull efficiency. This trend has spawned an evolution of prop designs featuring four, five and even six blades.  The additional blade surface helps offset slip induced by air bubbles flowing from the ventilation steps toward the props.

Cross section showing the thickness of a common prop blade.

Blade Thickness

For efficiency, blades should be as thin as possible to reliably handle a particular power range. A cross section of a typical constant pitch prop blade reveals a flat section on the positive (pressure) side and an arc surface on the negative (suction side) of the blade. Edges are usually 0.06″ to 0.08″ (1.5 mm to 2.0 mm) thick for aluminum props, thinner for stainless steel.

The cross section of a cleaver style prop blade is shaped like a wedge.

The blade cross section on surfacing props such as our T.E. Cleaver  and Pro Finish CNC Cleavers is wedge shaped. The thick trailing edge adds strength. Surface air ventilates a low-pressure cavitation pockets behind the trailing edge, enhancing efficiency.  The contour or shape of most propeller blade tips (other than cleaver) are round.

I will discuss propeller slip more thoroughly in Prop School – Part 6.

 

 

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