Hi-Performance Boat Operation – Part 2: Rigging Fit & Function

The 4.6L V8 300R FourStroke is very popular for single and multiple engine applications.

Spring is a great time for newbie and veteran performance boaters alike to get familiar with their craft. For starters, you should review your owners manuals — really, you should — and review the key components of your new boat.

The 300Rs on this MTI 340X catamaran feature the 20-inch Heavy Duty Midsection with rear tie-bar and side steer. The rear tie-bar and optional hydraulic steering cylinders provide enhanced engine stability for high speed applications. Surface piercing Sport Master gearcases are designed for use on boats capable of speeds in excess of 85 mph.

Performance boats vary widely in propulsion and size. Outboards come in 20, 25 and 30-inch drive shaft lengths to accommodate a variety of applications. Mercury (and other brand) outboards are fitted with a standard gearcase for most applications. Hulls that can take advantage of the high power-to-weight ratio of a 300R may benefit from its wide range of gearcase options. Similarly, Mercury Racing offers a variety of sterndrives for differing power capacities and hull types.

Mechanical control:  performance outboards such as the 60 EFI Formula Race, 250R and selected 300R models are rigged with a shift cable, throttle cable and fuel line.  Sterndrives, such as our 600 SCi throttle and shift is accomplished with cables, but steering is hydraulic.

Digital Zero Effort Controls.

Digital control: Selected 300R models and the 400R are Digital Throttle & Shift (DTS) Compatible.  We also have a full suite of DTS compatible sterndrives; 520, 540, 565, 860, 1100,  Dual Calibration 1350/1100, 1350, Dual Calibration 1550/1350, Class 1 Competition, 1100 Competition1650 Competition and 1750 Competition.  Here – mechanical throttle and shift cables are replaced with a single electronic cable.

Application Specific: Selected 300R models feature a heavy-duty swivel/clamp bracket and trim cylinder to endure the rigors of extended use in rough seas. The trim cylinder is actuated via a remotely mounted pump. A majority of today’s outboards feature trim systems mounted within the swivel clamp bracket assembly. Verado outboards come equipped with integral power trim and steering.  250R and 300R outboards come standard with mechanical steering.

Rear tie-bar 300R models feature the heavy duty midsection with a factory installed tie-bar mounting plate.

Two steering system types are available: Full Feedback and No Feedback. With Full Feedback, steering loads from an outboard or sterndrive are continually transmitted to the steering wheel. This is the preferred system used by tunnel boat drivers for “feel” of their craft while driving at the limit. One disadvantage: steering forces increase as engine or drive height or trim is increased. The steering wheel must be secured at all times to maintain control.

Mercury Racing sterndrive packages are equipped with power steering. The system requires actuation of external hydraulic steering cylinders.  Our Integrated Transom System (ITS) provides external power steering for Bravo One XR, Bravo One XR Sport Master and Bravo Three XR drive engine packages.  Power trim and steering cylinders are integrated in the M-series transom plate that comes standard with all engine packages featuring  M6 and M8 sterndrives.

A close up view of a 300R cat ready model featuring factory installed rear tie-bar mounting bracket and optional side steering cylinders. The tie-bar and side steering kit work together to enhance engine stability.

Performance boats with two or more outboards or sterndrives are rigged with both external power steering cylinders and tie bars. These components work together to minimize steering backlash and enhance drive stability.

The units tied together (outboards or sterndrives) should be adjusted parallel to each other, at rest, where play in the steering can be adjusted to zero. Always be sure to have a qualified professional check to ensure your outboards or sterndrives and all related components are mounted securely.























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Allison Renaissance

Allison sales representative Terry Wingo helped us locate 250R-powered Allison subject boats featured in our new R-Series outboard catalog.

It’s exciting to see the great amount of interest in our new 4.6L V8 250R and 300R FourStroke outboards. What’s particularly exciting is the adaptation of the product by Allison Boats. Allison for years powered its lightweight, high-performance vee-bottom hulls with our legacy 2.5-liter Mercury Racing outboards (electronic fuel injected and OptiMax direct fuel injected two-strokes).

Allison sales representative Terry Wingo helped us locate 250R-powered Allison subject boats featured in our new R-Series outboard catalog. A new dealer who was instrumental making the catalog photo shoot happen was Tim Powell, owner of Fastbass Marine in Grand Rivers, Kentucky.

Tim’s business has grown at a frantic pace and doesn’t show any signs of letting up.

Tim became an Allison dealer in October and signed on as an exclusive Mercury Marine dealer in December. He started out specializing in selling and servicing marine electronics out of his garage. It didn’t take long for that business to grow. With 16 boats stacked up he soon realized he needed to move into a larger 40-foot-by-60-foot building. It wasn’t long before he outgrew that facility and found himself moving once again, this time into his current 60-foot-by-100-foot building, which includes a 35-square-foot office/showroom.

Tim driving a XB-21 BasSport Pro for the Mercury Racing R-Series Outboard catalog photo mission.

Tim’s focus is providing tournament anglers the performance that comes with the race-proven Allison hull rigged for tournament fishing. His hull of choice is the XB-21 BasSport Pro. Allison also offers the XB-21 in a Prosport (large single-console) and 2+2 (Single/Dual Side Console with seating for four).

Tim’s focus is providing tournament anglers the performance that comes with the race-proven Allison hull rigged for tournament fishing.

“The XB-21 is very stable – a great platform to fish from. Single-console and dual-console models are both popular,” said Tim. “The single consoles are popular with hardcore anglers who appreciate the room to move around.”

Fashion Trend

Glenn Reynolds and Terry Wingo in Bumble Bee – one of the featured boats in the Mercury Racing R-Series outboard catalog.

Longtime Allison dealer Glenn Reynolds of Reynolds Racing  & Marine provided a bright yellow XB-21 BasSport Pro (Dual Console) for our photo mission. With the paintable accent panels on our new V8s, it was a no-brainer to color-match the accent panels and stripes with the boat. Deemed Bumble Bee, the boat was a magnet for photos. It jumps off the pages of our catalog and social media posts. Tim followed that up with his personal demo boat, an identical XB-21 BasSport Pro in electric lime green with color-matched 250R. That one made its debut at our Miami Boat Show media conference in January.

Tim’s personal demo boat made its debut at our Miami Boat Show media conference in January.

When asked what engines are favored Tim said, “I really push the 250R. I focus on that engine, as it is the power limit for most tournament fishing. After saying that, I may update the 250R for a 300R on my personal demo boat – just to see what it will do. However, with the color-matched engine graphics becoming as popular as they are, I think this one won’t be sticking around long.”

New Kid on the Block

At 36 years old, Tim is not only the newest Allison dealer, he is also one of the youngest. Tim said he has the upmost respect for veteran dealers Glenn Reynolds and Lee Sanderson of Sanderson Marine. I thought it would be interesting to get a perspective from the veteran’s point of view in terms of the resurgence in popularity of the performance outboard bass boat market.

The new 4.6-liter V8 250R and 300R FourStrokes have provided a whole new experience for 21-22-foot boats.

“I have experienced a vast evolution of engine technology in my long career of powerboat racing and running my dealership,” said Glenn Reynolds, owner of Reynold’s Racing and Marine. “I started with Mercury ‘Tower of Power’ inline six cylinder two-stroke engines. My first race engine was a 1968 Mercury 1250 BP. I then moved up to the 150 J Block. We then moved into the era of the V6 two-strokes: 225, 260, 280 and 300hp engines. These evolved from carbureted to electronic fuel injected models.

“More recently we adapted to the low-emissions OptiMax engines. Mercury has always been way out front in terms of performance. The new 4.6-liter V8 250R and 300R FourStrokes have raised the bar. They produce more power and torque compared to the two-strokes along with improved fuel economy. The new engines have provided a whole new experience for 21-22-foot boats. The ride is better and more comfortable. It’s just a safer experience overall.”

Veteran Mercury Racing and Allison Boats dealer Lee Sanderson as featured in the 2005 Mercury Racing outboard catalog.

“The torque the new Mercury V8 FourStrokes provide bring the big 21-foot Allison to life. The hole shot, acceleration, and top-end now rival that of the smaller 20-footers rigged with the 225 Pro Max engines of the day,” said recently retired Lee Sanderson. “The boat is up on plane in a boat length, and it sits you back in the seat throughout the bottom-end and mid-range. The engine is also much quieter and smoother compared to the two-strokes.”

A new Hemi Orange XB-21 BasSport Pro (single-console) made its public debut at an Allison factory open house Friday. We are looking forward to seeing this beauty on the water with its color matched 250R outboard.

The electric lime green and Bumble Bee yellow boats drew a steady stream of admirers in the Allison booth at the Bassmaster Classic over the weekend in Knoxville, Tennessee.




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Prop School – Part 6: Slip

Response to my Prop School series has been gratifying. It has generated a lot of good discussion (online and off) regarding propeller design, function and application. One of the most common questions is about prop slip. It is the most misunderstood of all propeller terms.

A wing moving through air produces a pressure differential: low pressure above the wing, with high pressure below it, creates lift.

Propeller blades work like wings on an airplane. Wings carry the weight of the plane by providing lift; marine propeller blades provide thrust as they rotate through water. If an airplane wing were symmetrical (air moves across the top and bottom of the wing equally), the pressure from above and below the wing would be equal, resulting in zero lift.   The curvature of a wing reduces static pressure above the wing — the Bernoulli effect — so that the pressure below the wing is greater. The net of these two forces pushes the wing upward. With a positive angle of attack, even higher pressure below the wing creates still more lift.

Marine propeller blades need to move through water with an angle of attack to create thrust.

Similarly, marine propeller blades operating at a zero angle of attack produce nearly equal positive and negative pressures, resulting in zero thrust. Blades operating with an angle of attack create a negative (lower or pulling) pressure on one side and a positive (higher or pushing) pressure on the opposite side.  The pressure difference, like the airplane wing, causes lift at right angles to the blade surface. Lift can be divided into a thrust component in the direction of travel and a torque component in the opposite direction of prop rotation.

Prop Slip 

Slip is the difference between actual and theoretical travel through the water. For example, if a 10-inch pitch prop actually advances 8-1/2 inches per revolution through water, it is said to have 15-percent slip (8-1/2 inches is 85% of 10-inches). Similar to the airplane wing, some angle of attack is needed for a propeller blade to create thrust. Our objective to achieve the most efficient angle of attack.  We do this by matching the propeller diameter and blade area to the engine horsepower and propeller shaft RPM. Too much diameter and or blade area will reduce slip, but at a consequence of lower overall efficiency and performance.

Calculating Rotational Speed, Blade Tip Speed and Slip

Our propeller engineers study props at the 7/10 radius (70% of the distance from the center of the prop hub to the blade tip). The 7/10 radius rotational speed in MPH can be calculated as follows:

And can be shown by a vector arrow.

Rotational speed.

Blade tip speed can be calculated using the following equation:

Forward speed is shown by an arrow in the direction of travel. The length of the arrows reflect speed in MPH for both the measured speed and the theoretical (no slip) forward speed.

Forward speed.


The original Quicksilver prop slip slide rule calculator.

Prop Slip Calculator 

Back in the day when the Everything You Need to Know About Propellers book was published, the Internet didn’t exist and you had to actually use these cumbersome formulas or rely on the Quicksilver Propeller Slip Calculator.

We Have an App for That

Today, you can get all of your prop information with our Prop Slip Calculator App. Download it for free from Google Play Store or Apple iTunes.

The Mercury Racing Prop Slip Calculator App is available for free download from Google Play Store or Apple iTunes.

Click here to see some real world examples on how I use the app.

I hope you have found my Prop School blog series both educational and useful. I’ve enjoyed sharing with you.


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Restore It and They Will Come

The iconic Miami Marine Stadium is listed in the National Register of Historic Places.

The 2019 Miami International Boat Show that concluded last week proved to be another successful event for Mercury Racing and Mercury Marine. This was the fourth-consecutive year the show was held on the grounds of the Miami Marine Stadium Park on Virginia Key. We felt this might be a perfect time to reflect on the stadium’s racing history and the possible future of the iconic site.

Originally designed for boat racing, the Stadium hosted musical performances of every type, boxing matches, water shows, Easter sunrise services, campaign rallies and community events from 1964 through 1992.

The Stadium, which originally seated 6,500 people, was designed by Cuban born architect Hilario Candela and constructed in 1963. It features a man-made basin that is 6,000 feet by 1,200 feet (wider than the National Mall in Washington D.C.). Originally designed for boat racing, the Stadium hosted musical performances of every type, boxing matches, water shows, Easter sunrise services, campaign rallies and community events from 1964 through 1992. It remains the only stadium in the U.S. built specifically for powerboat racing. Read more

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