Ginny Finch takes part in a practice for Out of Sight Dragons on Aug. 3 in Washington. (Matt McClain/The Washington Post)

Winifred “Winkie” Day leans against the long steering paddle of a 40-foot dragon boat, preparing to prod her team, the Out of Sight Dragons, into action.

“Attention!” Day calls out one recent day on the Potomac River in Southwest.

Maybelle Kagy, sitting near the dragon boat’s prow, waits for the final signal as Day’s command ripples down a line of paddlers. They lean forward, their paddles horizontal to the water.

And then, “Go!”

In front, Kagy starts pounding a steady tattoo onto the drum she carries, and the blades bite into the water. In a quick series of strokes, the boat surges forward. “Bury your blade! Get your hand wet!” Kagy yells.

It is the last practice for the Out of Sight Dragons before they race at Saturday’s National Harbor Dragon Boat Regatta. The local team is one of 35 from around the country to compete in the regatta. In dragon boat racing, teams are composed of 20 paddlers, a drummer and a sweep, or steersman.

What distinguishes the Out of Sight Dragons is that its members are all blind or visually impaired.

The origins of the sport trace back millennia, historians say. Now dragon boat racing has spread across the globe and become one of the fastest-growing sports in the United States, drawing dozens of teams to a rapidly expanding calendar of regattas across the country, enthusiasts say.

“There’s tremendous interest and excitement about the sport from small town America to large urban cities,” said Siv Somchanhmavong, president of the Eastern Region Dragon Boat Association, which oversees many dragon boat teams, clubs and races on the East Coast. In the past year, he estimates that the association has grown by 10 to 15 percent and from overseeing 12 festivals to 15.

Ginny Perrin, president of the United States Dragon Boat Federation, said there are about 6,000 serious paddlers around the country, and many more paddlers who compete but aren’t ongoing paddlers. They start by joining corporate or charity teams, such as those for survivors of breast cancer.

“Then they start to want to put more time in the boat,” she said.

The sport also appeals to people of all ages, she said — with divisions for kids as young as 12 up to seniors.

“You don’t see people aging out,” she said. “You see them taking their skills and continuing at an older division.”

In D.C., from 12 to about 20 novices show up at the Gangplank Marina on Water Street in Southwest to give the D.C. Dragon Boat Club’s free Saturday morning practices a try, said Jeffrey Kuhn, the club’s president.

The National Harbor Regatta is two years old but has signed up the maximum 35 teams for this year’s competition, according to Kuhn, one of the regatta’s organizers.

Out of Sight Dragons will be one of them.

The inspiration for the team came four years ago, according to founder Kagy. She had been working at Lions Camp Merrick, a camp for deaf, blind and diabetic people located in Southern Maryland.

Kagy’s son, who was the director of the D.C. Dragon Boat Festival at the time, first suggested she start a team for blind and visually impaired paddlers, she said.

Kagy said she soon realized that unlike many team sports, dragon boat racing might be one that visually impaired athletes could compete in, needing little more than a spot to sit and the ability to paddle to the beat of a drum.

The team is made up of a spectrum of paddlers, according to team member Sarah Presley. “There are people who can see pretty well, and people who are totally blind,” said Presley, who has “a little bit of vision” but lost most of her eyesight to congenital cataracts and glaucoma.

There is also a wide range of ages. At 37, Regina Crisafulli is one of the youngest Out of Sight Dragons. Oral Miller, 80, on the other hand, is among the team’s oldest paddlers.

For Out of Sight’s paddlers, the sport has provided the thrill of athletic competition but also something more.

It gives paddlers a “can-do attitude,” increased physical stamina and an increased will to advocate for themselves, Crisafulli said.

Kagy assembled a group of potential paddlers with the help of Miller, then head of the D.C. Council for the Blind, and members of the D.C. Dragon Boat Festival, who brought personal flotation devices, paddles and a drum to do a tutorial in a conference room. Soon after, they had a practice on the water.

“How will they become a team?” she remembers wondering.

But after just three practices on the water, the team competed in its first regatta.

“We showed ourselves and the public that blind people are really capable of doing something and being on a team,” said Kagy, remembering the other paddlers cheering for them after they finished their race.

“We really felt like rock stars. . . . On that day, we broke some stereotypes and showed the blind and visually impaired can participate in a team sport,” she said.

“It was a little chaotic to get everyone in sync,” said Sarah Presley, 46, of her initial practices with the team, which receives significant support from the D.C. Dragon Boat Club.

“It’s definitely a good sport for the visually impaired,” said Presley, one of the team’s paddlers. “When the drum beats, you know the paddle goes into the water.”

That concept is one that sighted paddlers use as well, according to Somchanhmavong of the Eastern Region Dragon Boat Association.

“One component of training is to paddle with your eyes closed, so paddlers will wear bandannas to focus on hearing and timing,” Somchanhmavong said.

On Saturday, Kagy said, the team will be using 13 blind paddlers and seven sighted ones, hoping to finish its 500-meter races in less than four minutes.

“We’re competing with ourselves this time. We still have much older people on the team,” she said. “We cannot expect to be like a young competitive team.”

Other members on the team are wondering how they will stack up against Blind Ambition, another team of blind paddlers traveling from Portland, Ore.

“I’m looking forward to competing against them, because I think we can more accurately evaluate our performance in competing against paddlers experiencing the same vision issues we have,” Miller said.

Back on the Potomac, the boat cruises by a weeping willow, and Day calls for a series of practice sprints just before the hour-long session winds down.

The team is tired but digs in for a couple of final 500s. Day, the coach, calls a start, and the boat lurches forward, momentarily unbalancing her. She wobbles, eyes widening, then rights herself, before steering the boat through the sprint.

“They all about knocked me off the boat,” she said.