By the time I had the opportunity to throw a leg over the saddle of the 2011 Kawasaki Ultra 300X, the word was long since out about the boat’s potent 300 horsepower. A new supercharger and intercooler, which promised to make the Ultra the highest-horsepower PWC ever produced by a major OEM manufacturer, was old news (see 2011 Jet Ski Ultra 300X Revealed by Charles Plueddeman), as were additional details like drive-by-wire throttle enhancements.

Jeff Hemmel testing the Kawasaki Ultra 300X. Photo credit: Andrea Wilson / Kawasaki

What I had no idea of — in fact what no marine journalist in the world knew until a few select members of the press were finally allowed to ride the first production models — was that horsepower would end up being only a small portion of the Ultra’s story. The feature that really pushed to the forefront was the newfound handling ability, which makes the Ultra a far more versatile boat.

Previous Ultras were known primarily as great rough-water machines. They bashed their way across ocean waves with total authority, which made the boats a favorite of offshore race enthusiasts. Where Ultras typically suffered in comparison to the competition was when conditions turned calm. A big, heavy-feeling watercraft, previous Ultras tended to sweep around a tight corner on flat water. By comparison, Sea-Doo’s RXT-X or Yamaha’s FX SHO hooked aggressively into a turn, exiting quickly out the other side with nary a slip.

Adding trim and horsepower has made the Ultra 300X into a more nimble performer.

With the 2011 Ultra retaining the same basic hull as its predecessor, I didn’t expect to find much of a change in that personality, but that’s where I was pleasantly surprised. Pinning the throttle during one of the brief flat-water runs during Kawasaki’s press intro in the Bahamas, I cranked into a turn and was shocked to feel the hull respond like a much smaller, much nimbler model.

What explains the new attitude? I think much of the answer lies in the fact that the ’11 Ultra now features something the boat has long foregone — trim. Electric trim allows the rider to lower the bow and plant the nose of the craft in the water, where it has a major influence on handling. Previously, the boat ran with a much higher running angle; now, areas of the hull that never before touched the surface are exerting their effect with every twitch of the handlebars.

Other changes come into play. The steering nozzle has also been shortened by 20mm, speeding the boat’s reaction time. Meanwhile the nozzle has been slightly enlarged, as has the pump diameter, which has grown to 160mm. Add in a new top-loading scoop grate and a redesigned impeller that features more blade surface area, with a leading edge that Kawasaki says improves hook-up and reduces cavitation, and you’ve got a boat that both takes in more water and delivers it more effectively out the business end.

Obviously, the increased overall power plays a role. The big change in the engine compartment is the new Eaton Twin Vortices supercharger. According to Kawasaki engineers, the previous design produced power in waves. In contrast, the new supercharger’s mirror-image, counter-rotating lobes promise to deliver power in a far more consistent flow. This boosts performance, but also smoothes out throttle response.

The Ultra 300X performs better in flat water, partly because its electric trim allows the rider to lower the bow.

In rough ocean conditions (with the bow trimmed high like the Ultra of old), I felt the change was noticeable, especially in the middle ranges of the powerband. Punch the throttle and the boat responds without hesitation. The same can be said for low-end acceleration on flatter waters. Any true comparison will have to wait for an actual head-to-head test against the competition, but from a seat-of-the-pants perspective, the 300X seems to deliver on its promise.

Certainly the stats would agree. According to Kawasaki, torque has increased from 177.2 ft-lbs to 201, max thrust has grown from 1585 to 1829 pounds, and boost pressure has increased from 11 psi to the current 17.3. Vast improvements all. In terms of the corresponding weight portion of the ratio, the boat has actually slimmed down by 44 pounds.

Kawasaki has reevaluated hull thickness throughout the boat, while beefing up key areas around the bow to handle added stress and keep things stiff. During our mostly rough-water testing, I saw 65 mph with a relatively heavy load of fuel. I’m fairly confident the boat will reach 67 in ideal conditions, which is the point at which the Ultra’s computer brain will limit speed in order to keep the Coast Guard happy.

A multitude of enhancements have been made to make sure the engine stays together and running smoothly at those speeds. The intercooler now features dedicated cooling lines to sap power-robbing heat build-up, as well as a dedicated discharge line to improve flushing. A new fogging port should make for simpler maintenance. The intake manifold has also been redesigned, and is now made of a lightweight nylon-based material. It also features O-ring seals, rather than a gasket. New top-end and exhaust-system components round out the upgrades, as well as redesigned crankshaft and engine cases.

As to those electronic-throttle add-ons, cruise control works smoothly; one button establishes the speed to hold and up-down arrow keys provide adjustment throughout almost the entire speed range of the craft. No-wake mode also performed as promised, allowing the rider to release the throttle for extended slow-speed zones. Kawasaki’s new ECO mode promises to reduce fuel consumption by as much as 15% when active, but what’s most surprising is how much power the boat retains when it’s active. According to Kawasaki reps, retaining the craft’s “sporty” performance was a must.

Elsewhere, familiar features have received welcome upgrades. The new info display is relatively easy to see, but what pleased me most was the replacement of the former display’s tiny, hard-to-reach mode buttons with larger alternatives. I also like the redesigned reverse lever. It feels better in the hand, but more importantly also changes the lever’s throw. That made it easier to shuttle between forward, neutral, and reverse when maneuvering around the dock. The seat has also been slimmed slightly at the front for improved comfort, and handlebars are wider as a result of the new switch assemblies. The width also gives the rider a little more leverage in the turns.

What’s not to like? I have minor concerns about the boat’s off-throttle-steering, the system used by virtually all PWC makers to give a momentary boost of steering power through the nozzle when the driver releases the throttle and turns the bars hard over in either direction, as when trying to avoid a collision. With so much thrust on tap, this boat’s pre-settle surge is quite strong. In potential collision situations that’s a good thing, but several times during my test ride I found myself releasing the throttle and turning the bars as I came upon our group stopped in the water, only to find the boat suddenly surging forward rather than drifting to a stop. It’s something to keep in mind when you’re approaching a group or come into a dock.

Price has also received criticism; with an MSRP of $14,499, the 300X is $1,600 more than the Ultra 260X. Keep in mind, however, it offers not only more horsepower, but multiple features the previous Ultra never had.

Which brings me back full circle to the beginning. All those redesign features combine to make a big difference in the Ultra 300X, and the added power makes for even more fun. Even so, I think it’s the new ability to trim this powerhouse that makes the Ultra an almost equal thrill on both rough water and calm.

hemmelheadshotJeff Hemmel was a senior editor at Watercraft World with work appearing in Consumer’s Digest, Boating, Motor Boating, and more. Jeff has won 17 writing awards, is an inductee into the International Jet Sports Boating Association Hall of Fame, and won its 2008 Lifetime Achievement Award for Outstanding Journalistic Contributions. For more info, visit his website.

Written by: Jeff Hemmel
Jeff Hemmel writes for, Boating,, and Powersports Business. The former Senior Editor at Watercraft World, Jeff is a multi-time award winner as well as a 2008 inductee into the IJSBA Hall of Fame. His first book, "The Anti-Pirate Potato Cannon...and 101 Other Things For Young Mariners To Try, Do, & Build On the Water," received a bronze medal in the 2010 Moonbeam Children's Book Awards.