Owners hear this engine roar as a kind of rough, hearty music. Environmentalists and others hear the same engine as nothing but noisome pestilence and a polluter of waterways.
The noise comes from jet skis, or personal watercraft (PWC) as they are known now. Around a million PWC now zoom and buzz across lakes and rivers in the United States. According to the Personal Watercraft Industry Association, PWC are the fastest-growing segment of the marine business.
But in their wake over the last several years they have left numerous court cases, divided communities, and a $1.2 billion industry trying to shake free of an image of irresponsibility.
In addition, the Environmental Protection Agency (EPA), citing small marine engines as one of the highest hydrocarbon-emission polluters, issued new, tougher regulations for PWC. The pressure is on manufacturers like Sea-Doo, Kawasaki Motor Corp., and Arctic Cat Inc. to cut noise levels as well as offer a more efficient engine.
By 1999 manufacturers will have to install fuel-injected engines designed to cut emissions by 75 percent. The two-stroke engines (the fuel cycle requires two piston strokes) of most PWC now run on a mix of gas and oil, discharging as much as one-third of the mixture unused into the air and water.
Personal watercraft are wildly popular because of their speed, size, and maneuverability. The pod-shaped crafts are powered by a inboard engine that drives a jet pump. Average cost is about $6,000. PWC offer a rider the fun of zooming across the water at speeds up to 60 m.p.h.
As sales of PWC have soared over the last decade, regulations have not kept pace. Injuries and deaths occurred out of proportion to incidents of traditional motorboat mishaps. In California last year PWC accounted for 55 percent of boating accidents, but constituted only 16 percent of the number of recreational boats in the state. Seven people were killed in California last year in PWC accidents.
Environmentalists say PWC can also disrupt wildlife habitats. Because of their shallow-draft design - the depth of water needed by the craft is a foot or less - PWC can easily sweep close to the shore, startling birds and animals and irritating many human residents.
"Manufacturers are dealing with all these issues," says Paul Carruthers, senior editor at Personal Watercraft Illustrated in Costa Mesa, Calif. "And they want to put to rest concerns that people have."
Advocates for PWC insist that initial problems and abuses that often characterized early PWC growth are not as prevalent now. As many states and localities have banned PWC drivers under 16 years of age, limited speed and shoreline access, and mandated boat-safety instruction and insurance, conditions have improved.
"I don't think the environmentalists can make a compelling case that modern personal watercraft are unfriendly to the environment," says Larry Stetson, president of Friends of Lake Crescent in Olympic National Park in Washington State. "In the early years, PWC were the motorcycles of the water," he says, "and young people were using them with questionable behavior. They just can't do it as much anymore."
But environmentalists and others are not sure so much has changed.
"Unfortunately, [personal watercraft] are still the most aggressive, high speed, and noisy recreational activity ever invented - with the possible exception of snowmobiles," says Russell Long, director of Bluewater Network at the Earth Island Institute in San Francisco.
The Bluewater Network, critical of the EPA standards as "weak and inadequate," brought suit last year against 20 marine manufacturers who sell two-stroke engines in California. "We are getting close to an agreement," says Mr. Long, who is seeking a ban on the older two-stroke engines that pollute California reservoirs and lakes. In addition, a bill in the state assembly, supported by Bluewater, would ban PWC on reservoirs.
Some of the PWC manufacturers are changing their technology and public relations. PWC maker Bombardier Inc. which manufactures Sea-Doo and has about a 50 percent share of the market, has introduced a fuel-injected engine and noise-suppression system for its 1999 line.
Sea-Doo claims the D-Sea-Bel system cuts the noise by 50 percent. But Boating magazine, in a recent test, reported the engine was only quieter at lower and midrange speeds.
"We are proactively reaching the EPA standards ahead of the mandate," says Bill Stone, a spokesman for the Sea-Doo division of Bombardier Recreation Products Group in Melbourne, Fla. "Our goal is to be environmentally friendly and a good neighbor," he says.
Manufacturers also claim PWC are being singled out even though traditional motorboats, and even kayaks, can be criticized for causing some of the same problems in disrupting wildlife.
Meanwhile the US National Park Service is considering banning PWC from parks or limiting their use drastically. At Lake Crescent in Olympic National Park, a management plan was suggested to limit PWC use to certain zones on the 12-mile-long lake after years of unrestricted PWC access.
Public hearings were emotional, not unlike reactions over PWC issues in other states and localities. "People are deeply and passionately concerned about the lake and PWC," says Barbara Maynes, a spokeswoman for Olympic Park.
A decision could come this summer, and will likely dovetail with the overall ruling from national park headquarters.
Perhaps the two most closely watched court cases involve the ban on PWC in the San Juan Islands in Washington and a proposed ordinance banning two-stroke engines at Lake Tahoe in California.
San Juan County commissioners enacted their region's ban in l996, stating that PWC were noisy, endangered swimmers, harmed the marine environment, and were not appropriate for the calm environment of the islands. A lower court ruled against the ban, and now, following arguments by both sides, the state Supreme Court will decide the issue.
In Tahoe, the Tahoe Regional Planning Association (TRPA) passed an ordinance in June 1997 prohibiting "the discharge of unburned fuel and oil by two-stroke engines." This will amount to a virtual ban on all PWC except the new Sea-Doo PWC.
The National Marine Manufacturers Association, the Personal Watercraft Industry Association, and local businesses brought suit arguing that PWC were being "discriminated against unfairly" and that PWC have not been shown to "violate environmental thresholds."
No one knows how the ordinance would be enforced if upheld by the court because the planning association does not have authority to issue criminal citations.
"One of the answers to all this is the four-stroke engine." says Mr. Stone. "It is the cleanest type of engine in marine use today, other than electric, and we are moving in that direction to become more environmentally friendly then we are now."