PORTSMOUTH — He may have arrived 40 minutes later than expected, but Barrington’s Trent Theroux looked anything but worn out as he passed through Stone Bridge at 4:42 p.m. Saturday to near the halfway point of his swim around Aquidneck Island.

To the whoops and hollers from supporters on both the Portsmouth and Tiverton sides of the bridge, a smiling Mr. Theroux — joined by several swimmers who crawled alongside him for this leg of his journey, as well as a powerboat and a kayak — acknowledged the love by putting both hands in the air.

Then he was off again, with the Tiverton harbormaster boat giving the procession a safe escort down the Sakonnet River basin.

As he did with his “Back to Block” swim last year, Mr. Theroux is using this 40-mile “Back to Newport” journey as a tool to raise money and awareness for RISE Above Paralysis.

The organization holds a special significance for Mr. Theroux, who was temporarily paralyzed after being struck by a power boat while swimming in Narragansett Bay more than 10 years ago. He’s hoping to raise $50,000 with the swim.

His journey began at Fort Adams in Newport at 7 a.m. Saturday.

Several supporters followed Mr. Theroux as he moved north along the east shore of the island.

Among them were Dave Foran and his wife, who live in Common Fence Point. They came to Stone Bridge to root Mr. Theroux on, then got into their cars and parked under the Sakonnet River Bridge before walking to the end of the railroad tracks. After that, they returned home to watch the swimmer cross the tip of the Point before he headed south back to Newport.

Mr. Foran, 77, swims up to a mile at a time and has been following Mr. Theroux’s lap around the island with great interest. He was most curious about how Mr. Theroux would manage the strong winds and currents under the Sakonnet River Bridge and around Common Fence Point.

“With this northeast wind, it’s a significant headwind,” Mr. Foran said after watching Mr. Theroux pass under the bridge around 5:05 p.m.

He was less impressed, however, by the turnout of people who cheered the swimmer on.

“It’s an absolutely incredible feat and we’re just surprised that there isn’t more interest,” said Mr. Foran. “People, I guess, don’t realize what’s involved. I mean, this may be the first time that anyone’s ever swum through here.”