EQUIPMENT TIPS AND ADJUSTMENTS FOR MAXIMIZING TOP-END SPEED
“Rigging for Speed” Equipment tips and adjustments for maximizing top-end speed – Joe Balog
Bass boat junkies have always been obsessed with speed. Fast boats were a novelty in the early days of bass fishing, but became a necessity as the advent of tournament bass fishing brought speed to the forefront. A fast boat meant shorter travel times between spots, which allowed more casts, and, in some cases, beating the competition to the best spot in the first place.
While larger boats and higher horsepower limits have led to fewer anglers pushing the envelope in terms of top-end speed, savvy tournament pros – particularly those accustomed to making long runs on massive bodies of water – still find value in getting all they can out of their bass boats. Here’s the inside track on going fast.
Proper Motor Height
The key to going fast on the water begins with having the outboard height set correctly. Once a laborious process, changing outboard height on most bass boats is now as easy as turning a dial to raise or lower a hydraulic jack plate, which is now standard on most rigs.
If you don’t have a hydraulic plate, invest in one if possible. Proper engine height can still be obtained with a manual plate, but it greatly increases the time and effort required to achieve the best setting.
Regarding engine height, many bass boat owners believe the key to speed is to adjust trim, but they’re off the mark.
“To go fast, you want the nose of the boat as low as possible,” says Alan Stinson.
Stinson is credited with designing and building many of the first modern bass boats in the 1970s for Skeeter. With more than 40 years of experience, he is responsible for many cutting-edge hull designs, and for helping evolve bass boats into what they are today. Any discussion of the evolution of speed in bass boats circles back to him.
Stinson says that keeping the nose low creates less wind drag and actually places less of the boat in the water. In contrast, trimming up lifts the nose, pushing more of the rear of the boat down and creating more hydrodynamic (water) drag.
“That causes a wake,” Stinson adds, “and a wake is a telltale sign of drag.”
Before setting engine height, consider two variables: First, be sure your boat has the recommended prop for its outboard. Each prop has an RPM range in which it performs best, and if your outboard isn’t capable of turning the prop within that range, consult your outboard manufacturer’s list (readily available through your dealer) of prop recommendations for the motor. Second, be sure to run tests in real-world conditions. If it’s tournament top-end you’re trying to improve, load the boat for a tournament.
“A tournament fisherman carries about 1,500 pounds of gear in the boat [including fuel, anglers, batteries, etc.], so we perform tests with that load,” says Mark Hanson, Mercury Marine’s lead hydrodynamic technician.
Hanson says boats react negatively to heavy loads, so weight must be continuously considered. In fact, Hanson often refuels several times throughout the testing cycle to ensure the heavy weight of full fuel tanks is taken into consideration. A different prop is often required to lift a boat that’s full of gear, and pitch size must be adjusted.
With the correct prop and weighting determined, run speed trials at different motor heights. Hanson begins by performing an anti-ventilation plate (AVP; commonly referred to as the cavitation plate) measurement. This determines the height of the AVP above the centerline of the hull. Boat owners can do it themselves by running a straight edge from the center bottom of the hull to the motor. With the motor trimmed down, the AVP should start about 6 inches above that line. Adjust the jack plate to achieve that mark.
From that starting point, run tests on the water to determine the best trim angle and whether or not the motor should be raised or lowered with the jack plate. The objective is to get most of the boat out of the water without the excessive use of trim while maintaining a smooth, stable ride. Through experimentation, you should be able to dial in what works best for your rig.
As mentioned, weight is a major factor in achieving speed. “Loading the front of the boat is enemy No. 1,” says Stinson.
Stinson, who was known to weigh each pro team member boat when it came into the factory, recalls once moving 273 pounds of tungsten weights and plastics out of the front of a well-known pro’s boat.
“Put all the heavy gear in the back,” he insists.
This allows the front of the boat to ride above the water line, with less drag farther back. The difference in top-end speed due to proper weighting could be as much as 7 mph, says Stinson.
To get a better idea of what a modern tournament angler’s tackle load weighs, I weighed a few tackle boxes from my front compartment. Remarkably, a small box of tungsten weights, along with a binder-style box of soft plastics (one of three I often carry), weighed close to 13 pounds. This likely represents less than 10 percent of the tackle found in the front of many tournament pros’ bass boats. All of it can rob valuable miles per hour.
How you get on pad makes a difference in speed, too.
“Trim it up on pad, then, when wide open, bump it down for a quick 1-2 count,” adds Hanson.
This pushes the nose down slightly, raises the rear of the boat up out of the water and reduces drag. Hanson claims two or three such adjustments can often gain an additional 3 to 4 mph.
Search for Speed Thieves
Anything on the bottom of the boat can rob top-end speed, so Stinson recommends in-hull transducers when possible, or having external transducers – like those used in side-scanning technology – mounted up and away from the boat’s running pad.
There should also never be anything interfering with the rotational side of the propeller (the right side for most bass boats). Anything mounted to the boat’s bottom to the right of the prop introduces air into that seam of water. The air then “sticks to the blades of the prop, and it won’t bite,” says Stinson. Cavitation is the result.
Know When to Quit
Speed fans might think there’s more to be done to increase speed. But for the most part, Stinson says, there’s not, short of actually modifying the hull. But what about wind drag?
“Boat speed is 90 percent hydrodynamics and 10 percent aerodynamics,” he claims.
Stinson says the biggest aerodynamic influence is hull drag. Removing pedestal seats, windshields and the like does little, if anything, to help gain top-end speed.
“At that point, you just need a different boat,” Stinson jokes.
A hydraulic jack plate is a valuable tool for maximizing speed.
Side-scan transducer placement must be carefully considered for best returns and minimal drag.