Their boats are parked right next to each other in the Lampson Pits - his big and blue and full of power, hers a little smaller, bright red and also plenty full of power.
They're Brian and Kayleigh Perkins, the Donny and Marie of the hydroplane world, though which is country and which is rock 'n' roll is anyone's guess.
"We're definitely a boat-racing family," Brian said while taking a break from Saturday's testing session on the Columbia River.
Kayleigh turns heads every time she climbs out of her UL-72 Miss Boat Electric, and it's not just because of her winning smile - though she's done plenty of winning to smile about already in her young career.
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But what grabs the attention - at least of the uninitiated fan - is that she is a "she" in a sport where there just aren't very many behind the wheel.
"I'm the only one driving this class and up," the 20-year-old from Black Diamond said.
But last year's triple-crown winner for the Unlimited Light Hydroplane Racing Association - rookie of the year, driver of the year and team of the year - said she would never have gotten behind the wheel if it weren't for her big brother.
"My older brother got me started," she said. "I got drug around going to his races."
Brian is in his first full season driving in the American Boat Racing Association's Unlimited series with the U-50 Miss Albert Lee and also pilots an Unlimited Lights boat when the schedules don't conflict.
"I've always liked boat racing," he said. "Kayleigh and I grew up on it. This is always what I wanted to do."
Perhaps that's because their parents, Kevin and Laurie Perkins, have been involved with the Seafair Waterside Committee for close to 40 years.
The kids grew up volunteering each summer at Seafair, and it seemed like a natural progression for Brian when he joined Bill Wurster's pit crew for the U-8 Llumar boat eight years ago at age 15.
The family bought a 1-liter inboard boat in 2000, and when Brian first experienced slicing through the water at 107 mph, he was hooked.
He started running Unlimited Lights in 2003, and this season on the unlimiteds series - he was fifth in driver points coming into the weekend - has been the realization of a dream.
"This is priority No. 1," he said, adding, "I love hydroplanes; it doesn't matter what kind. They're cool looking, they go fast, and I've always been a boat guy."
Now his sister is a boat girl, and she got her start - with some coaxing from big bro - in that same 1-liter boat.
"It was amazing," Kayleigh recalled. "There's absolutely nothing like it. I fell in love with it."
She was tearing up the Lighter than Lights racing division when her big break came in 2007.
Phil Bononcini, co-owner of the Miss Boat Electric and a longtime driver himself, was looking for a driver after Michael Flaherty switched teams. He decided to split the driving duties and gave Kayleigh a shot at some of the smaller races.
She finished third in her first race - the premiere of the Desert Thunder Regatta in Richland - and impressed Bononcini enough over the course of the season to get the start at Seafair.
"She did so good, we had to race her at Seafair," Bononcini said, "and she came in second."
That was huge for Kayleigh.
"Seafair was the height of my summer growing up," she said. "Taking second was so big. It was more meaningful even than winning the championship."
As the only woman driving full-time in the Unlimited Lights - and with none currently piloting an unlimited boat - she has to be considered the top female boat racer in America.
And she's proving that last season was no fluke. Her two wins this year are double her total last season. She came into the weekend with a 769-point lead in the driver standings, and Miss Boat Electric was only 81 points behind Jerry and Greg Hopp's Graham Racing Happy Go Lucky in the team race.
Brian and Kayleigh have bumped heads a few times in the Unlimited Lights series, with little sis typically getting the best of it. But her big brother shakes it off.
"It's fine," he said. "She has a much better boat."