The great folks at Indmar have done some fantastic work to debunk some of the "myths" around oil usage & consumption for our boats that get loaded with ballast for wakeboarding and surfing. We've had some good debates on this forum, so I hope this helps you out.
Bottom line is that if you load up with ballast to wakeboard or wakesurf, stay on the safe side by checking your oil level often and changing your oli & filter every 30 hours.
In the past few years we have noticed an increase in discussion related to oil consumption in engines that are used in high load activities, namely wakeboarding and surfing. Indmar has always believed engines used in low speed, high load activities can have a tendency to burn more oil than unloaded engines. Indmar now has the data to support it and a solution for our customers. We are supplying this information to you as a tool so you can inform and educate your customers on how they can better protect and properly service their engine especially if it is being used primarily under load.
The chart below depicts engine loads for a car, normal boat operation (no ballast), surf and wakeboard (full ballast). All of this data was derived from an LSA engine in a 24’ boat. The Wakeboard testing was performed using a highly ballasted boat with 5700 lbs. of ballast, a common configuration for events. Surf mode was tested using 2800 lbs. of ballast. The normal load curve was developed from boat testing with no ballast in the boat. The car data was taken from prior testing within the industry.
As you can see the horsepower required for wakeboarding and surfing is infinitely higher in comparison to a car or even in normal boating operation. With our LSA test engine loaded we see that wakeboarding requires nearly 450 horsepower at 23 mph and surfing requires nearly 380 horsepower to push out 11 mph while the car requires a mere 75 horsepower to achieve 80+ mph.
During our *480 hour durability test we noticed that when engines under normal load (no ballast) reached 30-35 hours between oil changes they experienced greater oil consumption due to the breakdown of oil viscosity. Oil was changed every 50 hours per the owner’s manual and this was the findings and our collective takeaway:
*Engine also had appropriate break-in hours
After 30 hours – ˝ qt. loss
35-38 hours -1 qt. loss
40-45 hours – 1.5 qt. loss
*Note With ballast added, the oil consumption could increase from the values listed above.
Oil viscosity breaks down much quicker in engines operating under greater loads, the most extreme during wakeboarding loads and speeds. With this information we are recommending that your service techs inform your customers that if they are operating their boats under these typical loads for wake sports they should change their oil every 30-35 hours. This will help reduce oil viscosity breakdown, increase engine life and minimize their concerns and experiences related to oil consumption. Boats that are predominantly used in normal boating or skiing conditions can maintain their 50 hour oil change regimen per the owner’s manual.
We hope that you found this research helpful and you continue to feel confident that Indmar will go the extra mile in maintaining that unique customer care and distinct customer service advantage. As always, we encourage any feedback to make us all stronger.