Jack Sarama said he wouldn’t be wakesurfing if he felt the sport was hurting local lakes.

LAND O’ LAKES, Wis.—Keith Montgomery was standing on the public pier of a glacial lake here when he saw a boat cruising along the shore so slowly that he didn’t think it would kick up a wake.

Instead, it sent a wave barreling toward a pontoon boat tied up at a dock nearby. A man on board clung to the railing to avoid falling backward and a woman on the dock tried to stabilize the craft as it bounced from below her knees to her waist.

“He was holding on for dear life,” said Montgomery, a 68-year-old retired college administrator and president of the Black Oak Lake Preservation Foundation, who spoke out to support a ban on boats making extra big wakes in the town of 950.

Speed boats designed to produce a wave so tall that a person can surf without a rope are rocking waters across Wisconsin and beyond. Pontoon riders tell tales of spilled wine, flying milkshakes and quiet cruises descending into chaos. Kayakers and paddleboarders have been traumatized. Opponents say the boats, which can cost well over $100,000 and are sometimes called the monster trucks of lake life, are eroding shorelines and damaging lake bottoms.

Keith Montgomery, president of the Black Oak Lake Preservation Foundation.

In Wisconsin, around 60 municipalities, including Land O’ Lakes, have banned the boats from using their full wake-enhancing mode, according to the Last Wilderness Alliance. Scott, a town near Green Bay, is facing a lawsuit by three property owners who call the ordinance vague, overbroad and illegal.

Wakesurfing enthusiasts blame much of the conflict on irresponsible wakesurf-boat drivers and misinformation. They say the wakes, typically up to 3 feet, dissipate quickly and after about 200 feet are no more dangerous to other boaters and the shoreline than a stiff wind.

“The lakes up here really are pristine. If I felt that what we were doing was hurting these bodies of water, I wouldn’t be doing it,” said Jack Sarama, a 27-year-old digital marketing entrepreneur who grew up in Land O’ Lakes.

On a recent morning, he eased a small surfboard off the back of a boat’s platform once it reached a speed of around 10 miles an hour, dropped the tow rope and danced back and forth on what ocean surfers and the Beach Boys could only dream about: an endless wave. Music thumped through speakers aimed at the back of the boat.

“I think people don’t like the noise, they don’t like the loud music, kids hooting and hollering. I think that’s a lot of the reason we’re facing this backlash,” said Sarama, who has designed “Wake Surfing Is Not a Crime” stickers.

Sarama surfs the Michigan side of West Bay Lake, where the sport is still legal.

People were once just as upset about Jet Skis, but so many people bought them that they were never banned, said Shawn Hill, a commercial mortgage broker from Illinois with a home in Land O’ Lakes.

“We don’t win any popularity contests and we’re always going to be outnumbered,” he said as he steered his wakesurf boat on the Michigan side of West Bay Lake, where the sport is still legal. “We’re the Big Bad Wolf, we’re going to come and blow your shore away.”

The National Marine Manufacturers Association says Wisconsin’s patchwork of restrictions are confusing. It instead calls for increasing the required distance wake surf boats should stay from other boaters and shore to 200 feet, the distance mandated in some southern states, from 100 feet currently in Wisconsin. (Opponents call for a distance of up to 700 feet.)

The conflict’s ripple effects can be felt in overflowing town board meetings, dueling yard signs and rival studies.

In Kent, Conn., officials recently called a town meeting to vote on whether to ban the boats from using their ballast tanks on Lake Waramaug. So many people turned up that the selectmen decided to change the vote to a referendum on July 31.

“I could have called the meeting and just let the people in that room vote, but I would have been lynched that night,” said Marty Lindenmayer, the town’s first selectman.

A battle is also raging on Lake Beulah in southeastern Wisconsin’s East Troy, where homes and summer camps hug the shore. Signs saying “Big Wakes Hurt Lakes” can be spotted around town, though several have been stolen, said Tom VanDenBogart, president of Protect Lake Beulah.

Brian Fons, a retired pharmaceutical salesman who organizes an annual fishing tournament on Lake Beulah, said he’s lost friends since he began raising concerns that wakesurfing boats are damaging fishing beds in a lake where depths vary greatly.

“It’s a very difficult lake for anyone to wakesurf without doing damage,” he said.

Brian Fons, a retired pharmaceutical salesman and organizer of an annual fishing tournament.

Retired firefighters Bonnie and Shawn Merath have scuba dived on Beulah to assess the impact of the boats on the lake bed at depths of 12 feet, where some plants were damaged, to 20 feet, where Shawn felt his body lifted up by around 3 feet after the boat passed.

“We were surprised by how much we got thrown around,” said Bonnie.

William Banholzer, an engineering professor at the University of Wisconsin, Madison, has been traveling to town meetings arguing research doesn’t support banning the boats. Banholzer, who owns a wakesurfing boat but says that doesn’t affect his conclusions, said studies show about 70% of a wave’s energy is dissipated at around 200 feet.

“If you’re taking my rights away, you better have a preponderance of evidence on your side, and they don’t,” Banholzer said.

Montgomery, standing on the dock where he first saw one of the boats, doesn’t buy it.

“I have a hard drive filled with these studies,” he said. “You can quote studies, but it’s people on the lake. What has their experience been?”