As the roar of rapids intensified, a maelstrom-like current sucked our raft toward the canyon’s towering wall, and my fingers tightened on the paddle’s T-grip.

“All forward!” the raft’s skipper cried, and we six crew frantically flailed at the churning white water.

No good. The aft end swung crazily toward the sheer stone face, beyond which the river thundered down a steep drop and formed an angry standing wave. I braced for a collision of rubber and rock, after which the raft inevitably would flip and spill everyone overboard. But the skipper tried one last, desperate maneuver.

“Back left!” he shouted, and those of us on the port side thrust our paddles forward while those at starboard pulled for all they were worth. Meanwhile, at the stern, the captain hiked out horizontally with a powerful, sweeping stroke, his helmet barely grazing the wall.

“Keep going!” he cried, and we dug our paddles into the waves like demons. “Now stop!”

The raft tilted crazily, spun sideways and plunged into the hole – but then, to shrieks and cheers, miraculously shot past the vertical wall, straightened out and drifted into a calm eddy.

“Well done!” I called to the skipper, and forgive my pride – it was my son, Tom, at the helm.

Tom and his buddy, Andrew Piccirillo of Old Lyme, have been spending the summer at an adventurer’s dream job: rafting guides on Utah’s fabled Green River near Dinosaur National Monument. Before being hired by Adrift Adventures in Jensen, Tom and Andrew were required to take a demanding two-week course on Colorado’s Arkansas River during the icy spring that covered everything from paddling techniques to first aid and rescue, and then went on to earn their captain’s licenses.

Last week my wife, Lisa, and I joined up with our friends Betsy and Bob Graham for a one-day rafting trip that represented one more phase in the father-son role-reversal.

I had introduced Tom to whitewater kayaking more than a decade ago – along with marathon running, mountaineering and a host of other outdoor activities, and now, as Wordsworth observed, “My heart leaps up when I behold a rainbow in the sky: So was it when my life began. The Child is father of the Man.”

We showed up at 8 a.m. on a bright, sunny morning that like so many days in the high desert of early August promised to turn into a scorching afternoon.

Tom and fellow guide Emmet Murray had already lashed two rafts onto a flatbed trailer and were loading supplies. After a 20-minute tutorial – the principal rule: obey the captain’s orders – we were fitted with life preservers and helmets, and piled into a van for a 45-minute bumpy ride over washboard gravel to the launch site at Rainbow Park. Emmet would be piloting one raft occupied by a family of four from Utah, while Tom would be the skipper of the other raft occupied by Betsy, Bob, Lisa and me, as well as Adrift guide Alana Zhang and office manager Sarah Jane Eaton.

Before hitting the water the van made a short detour to McKee Springs, where we hiked up a winding, dirt path to observe petroglyphs carved into the canyon wall more than a thousand years ago by a pre-Columbian archaeological culture known as the Fremont People.

Half an hour later we climbed back in the van and bounced along to the launch, where a short section of the Green River flowed in a deceptively lazy manner. At this time of the year, long after most of the mountain snow has melted, it cascades at about 1,600 cubic feet per second – a worthy rate that can produce Class III to Class IV rapids (on a scale of I to VI). In late spring the Green can roar along at more than 30,000 CFS and explode into a huge, boiling mess of terrifying hydraulics and “keepers.”

Our close encounter with the canyon wall occurred at a section known as the T.S.L. rapids, which by some translations stands for Taco Salad Lunch.

In an 8-mile-or-so journey of about four hours, including a lunch break and swim, we also successfully navigated the Moonshine, S.O.B., Houseboat, Inglesby and Last Chance rapids, just as famed explorer John Wesley Powell, a one-armed Civil War veteran, first did in a wooden boat in 1869. That three-month geographic expedition down the Green and Colorado rivers included the first recorded passage through the Grand Canyon.

As the sun heated up on our trip turkey vultures wheeled in a cerulean sky. The spectacular gorge, inaccessible by land and not far from where Butch Cassidy once roamed, is also home to golden eagles, bighorn sheep and mule deer.

“All forward!” Tom ordered, interrupting my reverie, and our raft plowed through riffles the rafters call “boogie water.” Some other rafting lingo:

   Spin to win: Revolve the boat to free it from a rock.

   Dump truck: Inadvertently tilting the raft, thereby tossing occupants overboard.

   Wrapping: Pinning the raft on a rock so that rushing water folds it in half.

  High-siding: Having one edge teeter skyward, requiring paddlers on the other side to readjust their weight toward the upward direction.

   Strainers: Tree branches that extend over the river and threaten to trap unwary paddlers.

   Corkscrew: Twist the raft violently in a river hydraulic.

   Hey-diddle-diddle: Choosing a channel that goes right down the middle.

   Romancing the river: Floating with legs akimbo instead of together, not recommended for those who fall overboard.

Happily, none of us experienced a dump truck or strainer, and our excursion presented just the right balance of thrills and relaxation, not to mention wondrous scenery.

By the time we pulled out at Split Mountain Bob and I were already planning a four-day trip that includes camping along the Yampa and Green rivers.

“Next year,” we agreed.