04/03/2000 Design News
Engine design and packaging are key to bringing surfer's dream to life
By John Lewis, Northeast Technical Editor
West-coast inventor Bob Montgomery first learned the way of the waves in the 1960s riding Southern California beachbreaks as a teenaged protege of surfing legend Duke Kahanamoku. Like many other surfers, Montgomery imagined a dream machine-a one-man hydrokinetic rocketship that would combine the freedom of surfing with a water ski's ease-of-use and maneuverability. "I wanted to ride a high-performance, motorized surfboard," recalls the 50-year-old ex-pro surfer.
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Now, due to his own determination and the availability of the latest materials and CAD tools, he is about to see his dream come true. It has taken the form of the Igniter 2000? model Powerski? Jetboard?, a new product from Powerski International, Inc. (PSI), a company he founded in the garage of his San Clemente, CA home. Montgomery is currently building a hundred prototypes for testing this summer, and production models should go on sale later this year.
He says he has three U.S. and 27 foreign patents, with 61 more pending worldwide, for this water craft that allows the rider to stand rather than sit, as is the case with most competitive products- and it's making quite a splash in the popular press. For example, the Igniter 2000 and its proprietary engine won the Popular Mechanics Design and Engineering Award for the new Millennium. It's also been featured in magazines such as Popular Science, Watercraft World, and Boating World. Among the Igniter 2000's engineering innovations:
A proprietary two-stroke, water-cooled engine that puts out between 30 and 50 hp, depending on displacement. The 6.5-inch thick, 50-cc engine weighs about 40 lbs, but use of a metal matrix composite material should drop the weight to about 28 lbs, Montgomery says.
An axial-flow jet pump that delivers 350 lbs of thrust through a proprietary gear-reduction transmission. The gear reduction, built into the bottom end of the engine, is new to the power watercraft industry. It enables engineers to match the engine's optimum rpm to that of the jet pump to enhance the craft's performance.
A design that puts the center of gravity under the rider's feet, rather than behind or in front of the rider as is the case with similar sports water craft.
Dual "hydrosteps" on the bottom of the hull that put the pivot point directly under the rider's feet, enabling high-speed planing and turning. They lift the craft partly out of the water as it skims along, and direct the line of water rushing past the rails during top-speed turns, stabilizing the craft.
A four-ft-long "armpole" consisting of steel cable and a sleeved wire harness covered by injection-molded rubber. The rider holds the grip on the end of the armpole that has start and stop buttons, left and right thumb throttles, speedometer and fuel gauges, and a safety kill switch.
A vaporless fuel system that improves environmental safety and prevents the loss of fuel through evaporation, prevents contamination, and maintains fuel integrity.
Design of the Igniter 2000, which has been a ten-year project, required overcoming several engineering challenges. Dealing with five significant natural forces: weight, buoyancy, hydrodynamic lift and drag, and thrust, Montgomery combined a high thrust-to-weight ratio with a hull/rail design and center of gravity placement that stabilizes the craft at all speeds. The design also enables high-speed planing and high-thrust G-force turns with simple shifts in weight of a rear-mounted rider.
But the real key was packaging the jet drive system inside the hull under the rider's feet. AutoCAD, from Autodesk (San Raphael, CA) and Pro/ENGINEER from Parametric Technology Corp. (Waltham, MA) were critical tools in the design process.
Sitdown & heavy. As a pioneer in the industry, Montgomery saw changes in the personal watercraft (PWC) design. As a standup watercraft, he says, the typical Jet Ski had proved relatively unstable-riders found it difficult to maintain a standing position because of the craft's forward center of gravity. Kawasaki's solution to the problem was to go from "standup" to "sitdown." The Jet Ski became a heavy, sitdown, square-railed directional jet-drive watercraft. The move by Kawasaki and other major industry manufacturers toward a heavy sitdown craft built up Montgomery's confidence in his plan for a much more hydrodynamic, standup watercraft. Where they went sitdown, he would go standup. Where they went heavy, he would go light.
"They lost the `personal' from the personal water craft when they went sitdown," he asserts. "The new machines were heavy, bulky, almost boats." So, Montgomery left the Jet Ski industry and set out to help pioneer the "jetboard" industry.
The first actual jetboard/motorized surfboard appeared in the 1960s. The "Bloomingdale Jetboard," a handle-less standup craft designed by Renard Storey, featured a low-powered (3-5 hp), 10-lb, 80cc engine capable of moving the craft at a speed of no more than 3-5 mph. Storey had designed his jetboard for surfers so they could eliminate paddling, according to Montgomery, who had heard about the original jetboard for years before finally getting a look at one in the early 1980s. When finally he saw the Bloomingdale board, he says, he knew why surfers hadn't taken to the low-powered craft.
"It was built with a `putt-putt' mentality," he recalls. "No thrust, so no turns." For Montgomery, the limitations of the Bloomingdale board only confirmed for him the efficacy of his own design, which had taken shape years before he finally saw Storey's design. In the years before ever assembling material for building his first jetboard prototype, he mentally "pre-engineered" his version of the standup PWC: a high-performance "power ski" board long, narrow, buoyant, lightweight, low-profile, and waterproof-propelled by a compact, powerful, jet drive system.
Montgomery continued to refine his ideas, and in 1981, he joined Surf-Jet Corp., Janesville, WI, the one manufacturer that shared his belief in the standup PWC. As new product manager for the company's power-operated standup craft, he designed the production hulls for the Surf-Jet Models 236 and 275, earning a place on the patent records for his efforts. Then, as the company's west coast marketing and sales manager, he began marketing the Surf-Jets. His extensive knowledge of design, engineering and manufacturing helped make the Surf-Jet a force in the PWC market in the 1980s.
But the Surf-Jet, as Montgomery saw while with the company, left plenty of room for the sort of hydrodynamic PWC he was designing and building. The position of the Surf-Jet's large engine-deadweight on the tail-placed the craft's center of gravity behind the rider, which cut down maneuverability. The standup Jet Ski's instability problems had stemmed from the placement of the craft's center of gravity in front of the rider.
Montgomery offered Surf-Jet his ideas for what would eventually become the Powerski Jetboard-with the center of gravity beneath the rider's feet, the rider's weight would dominate the craft to provide complete steering control. But, he says, Surf-Jet wasn't interested, and Montgomery moved on. In 1987, the entrepreneur in Montgomery set out to meet the challenge of pulling off a major marketing success without the benefit of initially having any money to pay for it. He started in his garage, hand-crafting his dream machine.
In 1990, to formally raise the funds necessary for taking the craft to the working prototype, pre-production stage, he formed the HydroForce Group General Partnership. During the next few years that the jetboard took shape, Montgomery struggled to keep focused on his mission, even working other jobs to pay the bills as he labored in his off hours. All the while he operated a "stealth" research and development campaign, strategically keeping the prototype hidden from the public (and competitors) as he slowly secured patents, trademarks and other intellectual property rights protections.
His work was not without conflicts, however. On one occasion he had to resort to fisticuffs to thwart a group of would-be thieves intent on stealing his design. Once the Powerski Jetboard was fully protected, Montgomery revealed his prototype to the world, securing product placement stories for the craft in national magazines. A card-carrying member of the Screen Actors Guild, he has also acted in and performed stunts for numerous TV productions and in two Hollywood motion pictures, including Kevin Costner's 1994 flick Waterworld.
In 1995, Montgomery co-founded PSI and moved to production facilities in Brea, CA, where he finished design of the Igniter 2000.
Designing the dream. The most significant challenge facing Montgomery in bringing his jetboard idea into reality was the engine. "I needed an engine with the horsepower-to-weight ratio that would give the consumer the ultimate jetboarding experience," he says. After an extensive worldwide search failed to turn up a suitable prototype, he says, he decided to build his own. Hiring Bjorn Elvin as PSI's engine project manager, Montgomery put Elvin's small-engine experience-gained while working at Husqvarna's motorcycle and chainsaw divisio