![woman riding a sea-doo watercraft on a brown river](https://www.popsci.com/wp-content/uploads/2024/07/SeaDoo_xRiver_KS188.jpg?quality=85&w=3776)
![woman riding a sea-doo watercraft on a brown river](https://www.popsci.com/wp-content/uploads/2024/07/SeaDoo_xRiver_KS188.jpg?quality=85&w=3776)
In 2023, Sea-Doo already had a personal watercraft (PWC, for short) on the market. Equipped with a supercharged 1.6-liter engine generating 300 horsepower, the RXP-X Apex 300 could cut through the water like a machete. Now offering an upgraded version of this machine, the powersports company swapped out the engine to crank out 325 horsepower, and it’s incredibly torquey with a squeeze of the throttle.
Sea-Doo says the RXP-X 325 is powered by the fastest-accelerating PWC engine to date, and media representative Timothy McKercher calls it a “superbike on the water.” Assisting the RXP-X’s overall capability is an impressive power-to-weight ratio, which improves its speed and agility even more. The hood is crafted with carbon fiber, a lightweight and incredibly strong material, and the hull is made from a superlight glass fiber reinforced polypropylene material. Ultimately, that means the RXP-X 325 has a power-to-weight ratio that rivals a Bugatti Chiron Super Sport.
It’s not all about speed, however. This machine is meant for buoy racing, a motorsport that requires threading through 15-20 buoys as quickly as possible. On glassy waters, the RXP-X evokes a track lap in an F1 car, or if it’s slicing through rough water, perhaps more like a supercross motorcycle. The deep V-hull carves a neat path and the watercraft spins with a tight radius, all the while keeping the rider from toppling into the wash.
“It’s a surgical tool,” McKercher says. “It’s that precise. I think the only thing that might turn quicker than this is a barrel-racing horse.”
If this watercraft is a horse, it’s one that could buck you off if you ride like a newbie. But Sea-Doo designed it to prevent that scenario as much as possible through ergonomic studies, high-tech hydrodynamics, heavy-duty testing, and education.
![two photos: one shot from above showing a woman turning on a watercraft vehicle. the other show the odometer of the vehicle from the rider's perspective](https://www.popsci.com/wp-content/uploads/2024/07/Sea-Doo_RXP-X.jpg?strip=all&quality=85)
Running down the river
Sea-Doo started with the Austria-made 1630-cc Rotax ACE 1630 platform and updated all of the engine components with completely new designs and engineering. That includes a redesigned intake system, new planetary-driven turbo booster, fresh engine control module, and a unique fuel pump system built with sensors that better control varying fuel pressure.
“It would be easy to make more horsepower by adding another cylinder or making a bigger engine,” McKercher says. “But power-to-weight ratio is key for almost all recreational products, especially watercraft. If we’re going to design this around the rider, we need for the engine to be small so we don’t have a big seat pedestal to work around. The compact 1.6-liter engine helps to keep the seat narrow where your thigh muscles hold onto the machine, and it has a flare over the knee area so the rider can drive their knees into the seat. That way, the strongest muscles of the body are being utilized.”
Officially, the RXP-X is rated for 69 miles per hour on the water, and it took me some time to get there as I warmed up to the idea. First, I had to get over my hesitations about piloting a high-powered machine in alligator-infested waterways. McKercher first put me on the (slightly) less potent GTR-X 300, which has 300 horsepower and a flatter hull. To compare, the deadrise–the angle between the hull and a flat surface–of the GTR-X 300 is 16 degrees, while the deadrise of the RXP-X is 23 degrees. The higher number indicates a more angular, cutting keel.
I drove 27 miles one way in the GTR-X 300 and back in the RXP-X, deciding that I prefer the nimbler RXP-X. Turning around is intuitive, and a manual steering damper can be easily adjusted on the fly to account for choppier waters. On flat water, a heavy damper isn’t necessary, but in chop it can be adjusted as desired to tighten up handlebar control, allowing the rider to stay on the power more steadily and for longer periods, both critical elements for racing.
As I pushed the Sea-Doo to the edge of my comfort zone in the waters of Lake Monroe and the St. Johns River in Sanford, Florida, I found myself belting out “Born to Run” and “Runnin’ Down a Dream” at the top of my lungs. My face was covered with a gaiter, which was pulled up to my sunglasses to protect my face from the sun; July Florida sun is no joke. For anyone who loves to go fast, the RXP-X is a dream, capable of incredibly fast speeds.
Engineered around the rider position
More than a decade ago, Bombardier Recreational Products (the Canadian company that makes Sea-Doo watercraft, along with Ski-Doo snowmobiles, and Can-Am all-terrain vehicles, side by sides, and motorcycles) enacted a design mandate that changed the relationship between rider and machine. This rider-centric philosophy means that Sea-Doo designers start by sketching the rider position first, building the machine around the person. With the rider in the priority spot above the watercraft, humans and machines are better connected.
“We can’t sit a rider on this machine and expect them to just hold on with their bare hands,” Tim says. “There are forces going in every direction. When the hull was developed, the design team had to complement that with an ergonomic riding design to not just keep them on the machine, but to utilize the power available.”
![a woman rides a watercraft vehicle on a river with trees on the bank](https://www.popsci.com/wp-content/uploads/2024/07/G0060341_9f46e0.jpg?strip=all&quality=85)
On an RXP-X, ergonomic lines facilitate a comfortable seating position. The handlebars are low-rise to maximize control, and angled footrests work with the natural position of the body. A sculpted saddle adjusts for a snug fit, an important factor for control and fatigue prevention.
While riding, the body can experience what McKercher calls the “typewriter effect.” As the machine hits choppy water, the rider slips backward in the seat, expending constant energy to pull back toward the handlebars. A rider slides back and pulls forward over and over. Over time, that becomes a fatigue factor, and the locked-in seat prevents that by keeping the rider closer to handlebars. That also helps with control.
Note: You should know that this is not a beginner’s PWC. I touched 70 mph a few times in open water across the lake, and losing control will likely end badly for inexperienced drivers. Having a skilled guide familiar with the area is helpful, too. Proceed with caution. And with pure joy.