As they crossed the big yellow buoy that marked the finish line Saturday, some paddleboarders sank to their knees in relief, careful not to disturb their balance as they recovered from miles of navigating the Peconic River.
Stand-up paddleboarders, along with kayakers and canoers, competed in 2.5-, 5- or 12-mile races in Riverhead early Saturday as part of the second annual Paddle Battle LI.
The event raises money for the East End Tourism Alliance and the Riverhead Foundation for Marine Research, two local nonprofits.
While three water sports were well represented at the Paddle Battle, the event highlighted paddleboarding, a sport that has exploded in popularity in recent years.
Jim Dreeben, owner of Peconic Paddler in Riverhead, which specializes in water sports equipment, said sales of paddleboards are growing faster than kayak sales and show no signs of slowing.
"This year it's probably doubled from last year" in popularity, Dreeben said. "It's something new, it's a challenge . . . it's a really good workout."
Last year, about 75 people participated in the Paddle Battle, said Bryan DeLuca, Saturday's emcee, president of the East End Tourism Alliance and executive director of the Long Island Aquarium and Exhibition Center in Riverhead. This year, more than 200 competitors signed up, hailing from as far away as Massachusetts.
The 12-mile race was a particularly difficult slog meant for the elite boarders -- the course took competitors out to Simmons Point in Aquebogue and back, and they faced headwinds and choppy water, said paddleboarder Nicholas Kostallas, 23, of Port Washington.
"Once the wind picked up, it really got difficult," Kostallas said.
Ally Wertheim, 14, of Setauket breezed through the 2.5-mile race on her paddleboard.
Last year, she competed in the kids' race, but this year she was the first female to cross the finish line in the 2.5-miler, even beating her mom.
"It was pretty much perfect conditions," Wertheim said.