Anne Walsworth used a megaphone to teach. Credit Ozier Muhammad/The New York Times

“I’M bored,” announced Shlomo Orenstein, 14, a seventh grader from Brooklyn, as he lay on a floating dock on the Harlem River on Thursday, picking splinters out of the wooden planks with his idle hands.

Moments later, his mood had changed considerably. He was seated in a sleek racing scull, those same hands wrapped tightly around a pair of carbon-fiber oars. He was rowing hard, sending the scull through the water.

He and a dozen other students from the Child School/Legacy High School on Roosevelt Island were at the Peter Jay Sharp Boathouse, an oddly old-fashioned building on the Harlem River, accessible by a gangplank and a string of floating docks.

The students were put to work carrying long racing shells to the water. They gathered around coaches from the New York Rowing Association, a nonprofit group that runs rowing clubs, teams and programs and that is based in the boathouse. This program exposes students from the city’s schools to an activity often associated with Ivy League universities.

OARS IN Students from the Child School/Legacy High School are learning to row on the Harlem River with the help of a nonprofit group, New York Rowing. Credit Ozier Muhammad/The New York Times

At the Child School, a charter school for children with learning and social disabilities, the students had been learning the basics and training on exercise rowing machines. On Thursday, they finally got out on the water in racing shells.

“Never step in the bottom of the shell, because it’s a thin fiberglass shell,” Anne Walsworth, the program’s rowing director, told the students before they boarded the wobbly vessels alongside the dock. And the oars, she said, are to be left floating in the water for stability.

Pairs of students were dispatched onto the river in quads, or four-seat vessels, and they sat in the middle, between two coaches from the boathouse.

At nearly slack tide, there was a slight current running south, with calm water and little wind. From a small motorboat trailing the rowers, Ms. Walsworth shouted instructions through a megaphone to two rowers, Joseph Clark Strong, 18, and Scott Binder, 19.

She told them to make a circular motion, dipping the oars into the water and lifting them out on the backstroke. She reminded them of each position, from the catch — the point at which the paddle is placed into the water — to the drive through the power portion of the stroke, to the finish and the recovery.

Earlier, Joseph had shown up on the dock with a top hat over his long, unkempt hair, looking more like a hard-rock guitarist than a crew member. But on the water, he got the hang of things quickly. “Some of the best first strokes I’ve ever seen, for sure,” Ms. Walsworth said. “Half of being a good rower is being comfortable in the water.”

Back at the dock, Joseph said, “It’s one thing to practice, but it’s completely different to be out on the water doing it.”

The narrow Harlem River, a tidal strait some eight miles long, flows between Manhattan on the west side and the Bronx to the east. The Sharp boathouse, at Dyckman Street and 10th Avenue, in Inwood, is in an area known as Swindler’s Cove, a spot that once bustled with competitive rowing dating to the 1850s.

Jaylisa Soto, 15, perfects her stroke. Credit Ozier Muhammad/The New York Times

New York Rowing, which contracts with the city to run the boathouse, offers programs that include youth and adult teams open to the public for a fee. Some slots are reserved for needy teens, like the one who wandered over one day from the nearby Dyckman Houses public housing complex, said Tom Curry, executive director of the rowing group. “He was throwing rocks at the boathouse, and I chased him down and convinced him to join the program,” Mr. Curry said. “Rowing got him into Wesleyan.”

For the students from the Child School, who have varying forms of learning or social disabilities, the daring river exertion seemed to relieve them of whatever physical lethargies they had. They seemed exhilarated to be in control of a piece of high-performance equipment, and being under the tutelage of athletic college students.

Sal Ferrera, director of the Child School/Legacy High School, said: “Since they started this, they have a whole different attitude about themselves. If their confidence really increases, they’ll do well all over.”

The experience was something similar to learning to ride a horse on a competitive thoroughbred. The shells cut silently along the brown river, in the shadow of steel bridges. One carried trucks high overhead on the bustling Cross Bronx Expressway.

The students slipped past some floating trash. But, somehow, being on the river seemed a brush with nature.

As Jaylisa Soto, 15, from Harlem, and Amanda Severe, 16, from Canarsie, Brooklyn, rowed, Ms. Walsworth reminded them which body parts to use during the stroke.

“Legs, body, arms,” she shouted, as the girls struggled to perfect the turn of the wrists necessary to flatten the oars while drawing them back for the next stroke.

Then, Ms. Walsworth said it was time to head in. “That’s it?” Jaylisa said. “Why?”

Shlomo, the seventh grader from Brooklyn, was certainly no longer bored. He became a rowing machine, and had to be told several times to dock.

“It was pretty cool,” he said. “I liked it because you don’t stay in one place.”