How Today's Wake Surfing Craze Can Be Killing Marine Engines - Engine Builder Magazine

How Today’s Wake Surfing Craze Can Be Killing Marine Engines

According to some experts, wake surfing has become one of America’s hottest sports. For those of you who are actively involved in building engines for pavement or off-road racing, marine motors may seem to be either an obstacle or an opportunity – and you would be right in both cases.

The power required to allow surfers to “hang ten” behind a boat puts enormous stress on a boat’s oiling system.
The power required to allow surfers to “hang ten” behind a boat puts enormous stress on a boat’s oiling system.

According to some experts, wake surfing has become one of America’s hottest sports. For those of you who are actively involved in building engines for pavement or off-road racing, marine motors may seem to be either an obstacle or an opportunity – and you would be right in both cases.

Wake surfing is the practice of, as its name suggests, surfing behind a powerboat on its wake. The sport’s origin is somewhat murky; some claims have placed its beginnings as far back as the 1920s, though there are definitely photos and movies from the ’50s and ’60s showing traditional ocean surfers hanging 10 on inland freshwater lakes. By the mid ’60s, surfboards were being designed and sold specifically for this type of aquatic activity.

Wake boarding’s and wake surfing’s success have led the boating industry to develop ways to capitalize on ever bigger wakes. That includes boards, ballasts and boats. Inboard ski/wakeboard boats are the most popular choice for this sport as the propeller is under the boat, and are less likely to make contact with the rider. Owners of inboard boats place ballast, such as water, lead weights, concrete, or other heavy objects in different sections of the boat in order to weigh the boat down and create a larger wake. Those in the know say the best weight configuration for wake surfing is to place the majority of the weight near the back corner side on the side the rider is surfing on. The deeper the boat is in the water, the bigger the wake will be overall.

One of the challenges boat owners face is that not all wakeboard boats are designed to be on their side all day. What does all of this have to do with you, the professional engine builder? Because of the boat’s operation, the engine could act as though it is low on oil since the oil pan will be on its side for long periods of time. With all of the other challenges marine engines already face, this can be an extreme test of a motor’s capabilities.

During a recent conversation with Len Groom, technical power manager – powersports with Amsoil, our conversation turned to the challenges engine builders and their customers face with marine engines. Admittedly, there is already some dissension in the camp — some marine engine builders believe that an automotive  guy just doesn’t “get it,” and some automotive engine builders who have had success jumping into the water say the dificulties are relatively easy to overcome. There are distinctions, to be sure, but the similarities often outweigh the differences.

“The sport requires a true screw-and-rudder type of boat, with the engine in the center,” Groom explains. “It’s not a stern drive boat. The motors you’re looking at could be like your 5.3L LS or 351 Fords; there’s a lot of four cylinders that they can use in different kinds of boats. But mainly, these wake-specific boats are some type of a V8 engine.”

With the engine mounted in the center, it uses a driveshaft to run a propeller and uses a rudder to actually steer the boat. When you’re wake surfing, Groom explains, the weight bags filled with water sink the back part of the boat.

“And then to really get crazy, they’ll set a trim tab down, which just creates more drag. So the front of the boat stands way up in the air. And the wave is massive enough that they can drop a board in the water, and physically surf behind the boat with no rope attached.

“You need to create a large enough wave,” he says, “and to do that, it really puts that motor at a precarious angle.”

Obviously, when you stand a V8 motor up on its end, physics take over and oiling becomes an issue.


Generally, says Groom, these boats use a wet sump oiling system so the front two pistons often get starved for oil. When that happens those front piston skirts typically get scuffed in the front couple of cylinders on those engines. This isn’t a problem with many other type of recreational boats because the angle of attack is so different.

The typical marine engine in a pleasure boat might spend 10 percent of its time idling, maybe 60 percent of its running time at cruising speed (4,000 rpm), and maybe 10 to 30 percent of its time running at wide open throttle (5,500 to 6,500 rpm). A performance boat might spend 5 percent of its time idling, and 95 percent of its running time at wide open throttle at speeds as high as 8,000 rpm.

“Your average waterski boat is typically on plane with the motor level,” Groom says. “With a ski boat, you put the throttle down, you get up on plane, and you’ll usually back out of it to try and maintain some speed so the skier can do his thing back there. But with the wake boat, the stress level changes, because number one, you’ve just added several thousand pounds of weight to the back of the boat. You’ve got it pitched up in the air, and you’re not allowing the boat to plane. So the amount of stress on the engine is even greater than when the boat is plane.

“Planed out, a boat will still put more stress on an engine than a car, because there’s quite a bit more resistance on the water,” Groom continues. “You pitch that boat up in the air and make that gigantic wave with all that drag, and now you’re stressing that motor even more. And then by denying it oil to the front several cylinders, because you’ve tipped it up on its back? All the oil is flowing towards the back of the crank.”

With all the stress and resistance on the boat and the motor itself, Groom says oil selection plays a key role in an engine’s life.

“The stress drives up your temperatures. So all of a sudden, you’re seeing elevated temperatures in the engine and in the oil,” he says. “When you already have less oil up there, the oil that is there, needs to be quality in order to provide a film for those pistons to slide in the cylinder bore. You’ve still got to have some oil in there that’s going to allow those skirts to interface with the cylinder liner, because they do touch.”

Stresses aside, boats are faced with other challenges related to their environment. Boat owners may not understand the importance of rust and corrosion protection with their marine oil. Generally, people believe ‘well, it’s oil, of course it provides rust and corrosion protection.’ In fact, in and of itself, oil without rust and corrosion protection built-in will rust metal in a relatively short period of time.


Oil companies actually elevate the amount of rust and corrosion protection that goes into a marine product. Because when owners shut these motors down, ultimately, just the way the engine shuts off, different valves will remain open depending on wherever that piston happens to be in the cylinder. With some valves left open, you’re exposing that cylinder to atmosphere either through the intake or the exhaust.

A marine oil will speak to that. Generally, a properly formulated marine oil will skew a little bit towards rust and corrosion.

You don’t want to rust up a crank or a cylinder liner. Because if you think about these boats, they sit while their owners are working during the week. And then they come, and they beat them up on the weekends, and then they sit for another week.”

Sitting is an issue with the boat’s fuel system as well. Groom says that based on his discussions with engine shops, more than half (and as much as 60 percent) of a boat’s issues are fuel-related.

“Many people blame it on ethanol in the fuel, because ethanol and water don’t mix,” Groom says. “The gas tank’s exposed to the atmosphere, and if the fuel sits too long it separates. The water and ethanol drop to the bottom of the tank, and the low-octane fuel that’s left over goes to the top. And then when they try to start the motor, it’s trying to run on water and straight ethanol.”

Rather than say ethanol is the enemy, of course, most engine builders have learned to deal with it. What they need to do is encourage customers to pay attention to it as well.

Even though boats are often considered a hole in the water that you pour money into, for engine builders, the wave of success in this market may be harder to ride than some other types of motorsports. But because enthusiasts continue to buy, use and abuse them, the boating market will continue to provide unique challenges and opportunities.

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