While 35-horsepower motors are the maximum allowed on much of the Kenai River, a draft study finds that -- at full throttle -- some popular boats produce smaller wakes with 40- or 50-horsepower motors than with 35s.
The 35 horsepower limit was imposed in the mid-1980s to deal with large, fast boats that were dangerous on the river and whose wakes eroded the riverbanks, said Jim Stratton, director of the Alaska Division of Parks and Outdoor Recreation. The limit slowed the boats, he said.
"Now, it's a fine-tuning thing," he said. "Is 35-horsepower the right horsepower to produce the smallest wake?"
Members of the Kenai River Special Management Area Advisory Board urged the public not to jump to conclusions from the study.
"There are a couple of ways to get at less wake -- less load, hull design, horsepower," said KRSMA board chairman Ted Wellman. "The board's goal was to look at all the factors that have an effect on wakes -- hull design, loading and horsepower -- and once all those things are considered together, to make some policy recommendations that make some sense."
Alaska State Parks and the U.S. Army Corps of Engineers' Alaska district asked the Corps' Engineering Research and Development Center in Vicksburg, Miss., to study factors affecting wakes on the Kenai River. Last summer, researchers ran several boats with different motors and payloads past wave gauges on Johnson Lake in Kasilof and on the Kenai River.
In addition to the horsepower effects, the researchers found that adding payload produced larger wakes.
With 35-horsepower motors running at full throttle, V-bottom boats produced larger wakes than flat-bottom boats of similar weights.
Stratton said he remembers fishing the Kenai River before the 35-horsepower limit.
"I felt like I was trying to fish in the middle of a pinball machine. Boats were zooming up and down the river at incredible speed, and there were wakes every which way," he said.
Joe Connors, president of the Kenai River Professional Guides Association, said he has argued for years that with 35 horsepower, Kenai River boats are underpowered. With 35-horsepower motors, his Willie Predators will plane carrying four passengers, he said, but with five, they bog down.
He favors raising the limit to 50-horsepower, but opposes eliminating it altogether.
The boat he used before the limit would do close to 60 miles per hour, he said.
"I don't think we want to take the limit off, because at a certain point, there would be an intimidation factor," he said. "The range between the slowest and the fastest boats isn't more than 15 miles per hour, now, but if you take it off, the difference could be 50 miles per hour."
Some boaters do not know how to operate around faster boats, he said, and some people do not operate fast boats safely. Reasonable behavior must prevail, he said.
"We've got it to the point where we're not having many accidents. We want to keep it that way. I don't think we want any drastic changes," he said.
If the state restricts hull design or passenger loads to cut wakes, he said, the limits should apply to everyone, not just to guides.
Wellman said the KRSMA board wants to study the draft report and hear from its author before trying to make policy recommendations. He said the one thing he does not want is for people to focus on parts of the report that support their own special interests and ignore the rest.
"It's very complicated. It's almost like reading the Bible. You can find anything you want in it," he said. "... There are other issues with wakes than erodability of the banks. If someone is throwing a huge wake, making it impossible to fish on the bank or for smaller boats to safely navigate the river -- there are other things. They all mesh together. You can't change one without changing the other."
Once the board understands the science, he said, it will consider what is best for the river.
KRSMA board member Lance Trasky, regional supervisor of the Habitat and Restoration Division of the Alaska Department of Fish and Game, said the study provides solid information about how hull design, horsepower and loading affect wakes, but that is only part of the equation.
"The next question is, what does the wake do to the riverbanks?" he said.
The answer may vary from place to place. Gravel banks are very subject to erosion, he said, while rock banks are resistant.
About six years ago, Joe Dorava, a U.S. Geological Survey hydrologist, studied the effects of wakes on the riverbanks, Trasky said, but that was just a preliminary study.
"With something like this, that's sensitive, you need to do an exhaustive study so you know you're confident with what you have," he said. "The other thing you have to look at is, how much difference is there between 35 horsepower and 50 horsepower?"
Meanwhile, he said, if Alaska State Parks boosts the limit, people may negate the effect on wakes by using bigger boats.
Trasky also said safety concerns figured high when the 35-horsepower limit was imposed.
"It had to do with safety and the danger of those big boats going too fast and swamping other boats," he said.
Asked whether 35 horsepower is the right limit, he asked, "From what aspect -- safety, or damage to the riverbanks?"
The KRSMA board is to discuss the study and hear from its author during its meeting May 24 at 7 p.m. at the Kenai River Center on Funny River Road.
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