Have you ever wondered why vehicles on land have multiple gears that are needed to get them going, but that marine vessels like jet skis don’t seem to shift at all? Why lose the stick when you get in the water? What is the point!? Luckily, this article can explain the science behind the direct drive and how it works for a jet ski.
Do jet skis have gears? Nope. Jet skis do not have gears because they use the direct drive. Unlike vehicles on land, jet skis only need the one gear of the engine to propel itself forward (or in reverse) because there is little point for multiple gears to be used for watercraft.
Why Don’t Jet Skis Have Gears?
Jet Skis and other watercraft are not like land vehicles. When a car or truck wants to start driving, they must start in first gear because they need more torque to get moving up to speed. The build-up of RPMs needs to be gradual. However, water speed is based on the actual RPMs meaning that there is no need to start at a watered down RPM in first gear, it would just make the propellor very weak and slow. Instead, the motor spins at variable speeds and can be revved up or down as speed is increased or decreased.
Another reason is there is no room for a transmission in a jet ski. The motor bays are already tight enough without a transmission. The added weight would also be a negative to the enjoyment of your jet ski.
What Is Direct Drive?
Jet skis and other watercraft use direct drive to power themselves. This means that the craft and propeller get the full power of the motor because there is no need to ease into the higher gears. Direct drive is important for boats and jet skis because they lose their momentum in the water quickly, which is not valid for vehicles on land. If you were shifting gears, you could lose momentum and lose speed.
Are There Any Jet Skis With gears?
It would only be possible to have a jet ski with two gears for lower and higher speeds. Otherwise, the gears and their ratios don’t fit the size and RPM speeds needed for the pump. In other words, gears on Jet Skis is a fantasy that may have dreamers thinking of making the most excellent backflip jet skis of all time, but end up spinning their wheels (impellers) in the long run with a dream that just can’t come true.
Conclusion
No, jet skis don’t have gears because they don’t need them. Instead, they and other watercraft use the direct drive to put the full RPMs into the impeller or propeller so that the speed is not lost. Momentum tends to be forgotten quickly in the water, that is why direct drive and the full power of the motor at all times makes the most sense.
Jet Skis don’t need gears, plain and simple. The dreams of hybrid PWC with gear ratios built to do insane tricks have never worked out, according to our research on many different online PWC forums. Maybe one day, but not yet.
