You got your boat and, from the moment you pulled away from the dealership, it’s attained a certain speed. But if you’ve got a craving for more, you’re going to try to make it go faster, perform better and run more efficiently. OK, you just want to go faster. But after searching the Internet for possible modifications, you wound up as confused as Justin Bieber’s image consultant. That’s where we come in.
Here are five ways to boost speed and performance. Blueprinting focuses on the hull and, in high-performance applications, the drives. The easiest upgrade might be changing the prop or having it fine-tuned. For the engine, you can have the electronic control module (ECM) reflashed or you can add a supercharger. Finally, outboard enthusiasts might consider installing a jack plate. Read on and learn about the pros and cons of going after higher speeds.
Speed Gain: 2-4 mph
Cost Per MPH Gained: $375
Bottom Line: A modest increase without touching the engines
If you are wary of making modifications to your engine, consider having your boat’s bottom “blueprinted.” Many enthusiasts believe blueprinting involves literally creating a blueprint. Actually, it’s a process of restoring the bottom to its original specifications.
“Any boat can benefit from it, but the faster you go, the more you accentuate it,” said Craig Wilson, president of Wilson Custom Marine in Stuart, Florida, the blueprinting leader of the go-fast world. Wilson Custom Marine fine-tunes bottoms of performance boats and also blueprints sterndrives with acclaimed results.
Mass-produced boats such as runabouts and cruisers in the 25- to 30-foot range can have myriad imperfections, including too much hook or rocker in the bottom or flaws in the strakes or chines. These could be the results of imperfections in the mold from which the boat was constructed or the result of a boat being stored in the off-season on too short a trailer. When a boat has a hook in the running surface, that means the aft section of the bottom angles down. It acts like a giant trim tab, forcing down the bow, hampering lift and scrubbing speed. The only way to combat hook is with excessive drive trim, and then you’re losing performance because the propeller thrust is angled more up than horizontal. The best way to check your boat’s bottom for a hook is with a straight edge at the transom. When a fiberglass repair shop removes the hook, it will free up the boat and let it ride on its intended lines, increasing top speed and improving all-around performance.
Rocker is the opposite of hook. When a bottom has too much rocker, its aft sections round up and, in the extreme, would look like half a football when viewed from the side. The boat rides bow-high and you can’t use the positive trim you’d normally apply to lift the hull and reduce wetted bottom surface. Blueprinting would remove the rocker and help the boat ride on its lines.
Wilson said that his company could take a 55 mph runabout and have it running close to 60 mph after blueprinting the bottom. Wilson Custom Marine also blueprints drives, including the Mercury Racing Sport Master lower unit for Bravo One drives and NXT, SSM and M8 drives. The service ($3,000 for a pair of Bravo One Sport Masters) custom-matches the drives to each other and to the boat, eliminating flaws that affect how water runs off the drives. On high-performance boats, the process has delivered up to 10 mph increases in top speed. Once the drives are refined, Wilson Custom Marine offers a ceramic coating that will keep the drive finish clean for two years for $250 per drive.
Cost: $6,799.99 (Black Whipple charger for a MerCruiser 350 Mag MPI; $7,299.99 for polished.)
Speed Gain: 10+ mph
Cost Per MPH Gained: $679.99
Bottom Line: A big investment that will yield big gains
For the most substantial power gains, bolt a supercharger to your boat’s engine. You will void the warranty and reliability could be compromised, but you’ll be going a lot faster. Whipple Industries says a MerCruiser 350 Mag MPI can achieve up to a 50 percent horsepower gain, taking power output from 300 hp to more than 400. On a MerCruiser 496 Mag HO, a Whipple supercharger increased horsepower output from 425 hp to a maximum of 657.1, according to a dynamometer readout on whipplesuperchargers.com.
Driven off the engine’s crankshaft with a pulley, a Whipplecharger compresses the fuel and air mixture before it enters the cylinders. When more air and fuel pack into the cylinders before the pistons compress the mixture, the resulting explosion is more violent, creating more power.
The Whipple kit comes with a recalibrated ECM to control idle, fuel, spark and knock and all the components required to complete the installation. The supercharger will not increase height requirements in the engine compartment and needs only two inches extra of forward space. It does not come with the kit, but Whipple recommends you also upgrade your engine with a medium-duty oil cooler.
Adding that much power to an engine/drive combination will require at least a propeller change and possibly a new gear ratio in your drive, so installing a supercharger represents a serious upgrade.
Another popular aftermarket supercharger is the Procharger, which is a little different from the Whipple in technology but promises similar power increases. The Procharger kit for a 350 Mag MPI reportedly boosts power output to more than 500 ponies.
3. ECM Reflashing
Cost: $595 (Stage 1 ECM reflashing)
Speed Gain: 1-2 mph
Cost Per MPH Gain: $297.50
Bottom Line: A minimal gain for the same price as a new stainless-steel prop
If your boat gets its propulsion from a fuel-injected engine and you want to increase the power output without, arguably, risking the reliability, have the ECM (engine control module) reflashed by Whipple Industries (whipplesuperchargers.com), the company best known for its superchargers. The ECM is the brain of a fuel-injection system. It controls the fuel and airflow as well as the engine timing and spark curve. Increasing the amount of air and fuel going into the engine’s cylinders creates a more potent explosion when the piston compresses the mixture, resulting in greater power output. In a Stage 1 upgrade on a MerCruiser 350 Mag HPI, Whipple increases output by 20 hp and torque by 20 pound-feet by modifying the fuel and spark curve. Reflashing also raises the maximum rpm, which might mean that you have to run a bigger prop. There are downsides, depending upon your priorities.
Reflashing the ECM will void your engine’s warranty and may reduce the drive-train longevity, according to marine engine makers we interviewed. Racers often take these risks in the quest for the checkered flag. Recreational boaters need to carefully weigh these factors before making a decision to reflash their boat motor’s ECM.
4. Jack Plates
Speed Gain: 2-7 mph
Cost Per MPH Gained: $106.42
Bottom Line: A good move for overall performance with any outboard
It’s irrefutable that the less there is of a given appendage in the water, the less drag it will create. Hence the development of jack plates for outboard motors. A jack plate installs on the transom, and the outboard motor is mounted on the jack plate. Raise the plate and there’s less of the outboard motor’s lower unit in the water. This reduces drag and improves efficiency. Among the most popular jack plates are the corrosion-resistant aluminum models from CMC Marine (cmcmarineproducts.com).
Manual jack plates don’t allow you to change the height while the boat is under way; electrohydraulic versions let you adjust engine height on the fly using up/down switches at the helm. Additionally, because the plates position the motor between four and 10 inches farther aft, engine trim will have greater influence, which improves efficiency as well. Installation is straightforward, involving no more than drilling a couple of holes and filling some old ones for manual plates and running hydraulic hoses and wire harnesses for the power versions. If you install a jack plate, you should also install water intakes on the outboard’s nose cone (“low-water pickups”) to ensure a steady flow of cooling water as the lower unit is elevated.
Speed Gain: 2-5 mph
Cost Per MPH Gained: $200.46
Bottom Line: The easiest way to pick up a few miles per hour
The easiest way to move the speedometer needle is to switch propellers. For a runabout-style V-bottom equipped with an aluminum prop, replacing the prop with a stainless-steel model will usually yield a gain of about 2 to 3 mph. Because stainless steel is stronger than aluminum, the propeller blades don’t flex, and the blades are thinner, which lets them cut through the water with less resistance. Mercury’s Enertia prop is made of an alloy that’s stronger than stainless steel. When I switched from a stainless-steel prop to the same size Enertia on my 23-foot Chaparral bowrider powered by a MerCruiser 350 Mag MPI Alpha One, I picked up two more miles per hour, so going from a stock aluminum prop to the Enertia could gain you up to 5 mph in additional speed.
If you already run a stainless-steel prop, have it custom-tuned at BBlades Professional Propellers (bblades.com). Tell the pros what you want to achieve and BBlades will customize the prop accordingly.
“If somebody says he has a 27-foot Fountain or a 17-foot Four Winns, immediately a recipe pops into my head because we’ve done so many,” said BBlades President Brett Anderson. Adjustments can be made to the propeller diameter and/or pitch, the cup of the blades and the size of each blade. BBlades charges $98 per hour and breaks each hour down into 15-minute increments.