We set out to kayak the entire Charles River. It was that or pickleball.

I know all this because, on a golf course with three high-school buddies in October 2022, we hatched a plan to paddle the entire length of the Charles.

By then middle-aged, we were talking about life and how best to spend our next chapter. Pickleball may have been mentioned, but then my friend Gene Hurley, who has lived most of his life within a stone’s throw of the Charles, shared his long unrealized scheme to paddle it. “The whole thing,” he said. I was intrigued.

Neither of us owned a kayak. Months later, we paddled our banged-up boats into Boston Harbor after an adventure that took us over beaver dams, into unspoiled slices of wilderness, past modest homes and stately manors, through 23 cities and towns — and made our year.

As noted, the Charles River “starts” a little over 80 miles from the harbor. But the paddler’s map published by the Charles River Watershed Association picks things up at the North Bellingham Dam, 65.4 miles from Boston Harbor. We planned to launch our journey somewhere upstream from the dam.

Depending on rainfall, sections of the river upstream can be unnavigable. At times your boat will bottom out. Even when the water level cooperates, there are countless obstacles. The 19 dams on the river are just the start. Fallen trees lurk around seemingly every bend of the Upper Charles and frequently force awkward portages.

With work and personal lives to juggle, we didn’t have a great sense of how long it would take us to complete our expedition, except that it wouldn’t be just a day or two. We planned piecemeal, one leg of the journey at a time. But the goal was clear: to paddle into Boston Harbor by the end of the summer.

With little previous kayaking experience, we decide to test the waters by launching an initial leg on April Fools’ Day at Bellingham’s Box Pond, through which the Charles flows. We’re both thinking the same thing. Two fools in over their heads.

The Native American name for the Charles River is Quinobequin, meaning meandering. We quickly understand why as we find our way downstream through the lovely, bird-filled Bellingham Meadows, where the narrow switchbacks eventually lead us on a twisting route to our first real test, a dark passageway under Interstate 495.

At certain times, when the water is too high, the tunnel is impassable for paddlers. We quickly size it up and decide to try to squeeze our way through, the top of our heads scraping the ceiling. Eventually, we are ejected back into daylight, smiling with relief and wiping spider webs off our faces. We go a bit farther on this day, scooching our boats over a burgeoning beaver dam before finding our planned ending spot at Maple Street in Bellingham, where we had parked one of our cars before starting.

Our next time out, we are joined by Jim Grant, another member of that initial golf foursome. It is his first time in a kayak and he is on edge. We put in at Bresnahan’s Landing in Medway and cruise downstream through Populatic Pond between Franklin and Norfolk.

Before long, we settle into a rhythm. That doesn’t last long before we get spun around by some shallow, rocky quickwater under bridges at Myrtle Street and Dean Street along the Norfolk-Millis line. We exit the water at a canoe launch by Forest Road in Millis, toasting our fun with some hazy IPAs.

Our confidence buoyed, Gene and I decide to backtrack upstream to find the farthest reasonable point from Boston Harbor to put our boats in and mark the starting line of our grand adventure, and also to fill in the short gap on the route we left between legs 1 and 2. We set off on another gray day from Howard Street in Milford, upstream from Bellingham’s Box Pond, where we first got our feet wet on Day 1.

We pass a small farm and slide under several creepy bridges, then fight our way through an overgrown thicket blocking the entrance to the pond. Having stashed Gene’s truck there, we load the boats up and leapfrog the section we already did with the scary tunnel under I-495 and resume our day’s journey in Bellingham upstream from where the Pearl Street Mill once stood. At that spot the map marks the Caryville Dam, but it was removed a few years ago.

Nevertheless, we run into an obstacle early on: a large iron girder that spans the channel from the days the river ran under the now dismantled mill. With a strong current pushing us into the barrier and high walls on either side, there’s no easy way out. We manage to carefully float our boats under the barrier while we scramble over it. We end at dusk by the Sanford Mill Dam between Medway and Franklin.

When we reconvene in late May, we cover about 10 miles on a glorious day, passing through Medfield and Sherborn. It’s the first time we see other boaters on the river. We take time to check out South End Pond, then slip past King Philip’s Overlook, a scenic bluff above the river, and pull out for a break to explore the old Medfield State Hospital campus on foot before finishing for the day.

A couple of days later, Barney McFarland, the final member of our golfing group, tags along for the fifth leg of our journey. Blue herons, a bow fisherman standing in the wash of the South Natick Dam, and a series of spectacular mansions near the confluence of Wellesley, Needham, and Dover highlight our day.

We are starting to get a little cocky. As if to keep us in check, several weeks later, a seriously ornery swan guarding its cygnet in a narrow stretch of water threatens to swamp my boat, then Gene’s, forcing us into a semi-panicked escape. Once in the clear, we hustle around Cochrane Dam in Needham, go under Route 128 for the first of three times, and into Dedham.

Not far downstream from all the multimillion-dollar real estate we passed on our previous leg, we come upon the only trailer park inside Boston’s city limits. We end our day at the Millennium Park boat launch in West Roxbury to the sound of the Needham Heights commuter rail train rumbling outbound.

Some weeks later, we make our way through more of Needham and Newton, getting out to get around three more dams. On our final portage of the day, we haul our boats on foot a couple blocks down Washington Street in Newton Lower Falls. Struggling with the kayaks, we leave our boats on the sidewalk and pop into a Dunks for a boost. To my disappointment, the woman behind the counter betrays absolutely no reaction to the sight of two life-jacketed guys with kayak paddles. We end the day with a picnic delivered by my elderly mom at Riverside Park in Auburndale, near where she grew up.

On our penultimate leg, Gene and I put in on a gorgeous Saturday in early September and paddle 9 miles through Waltham, Watertown, and into Allston.

We have three more portages around dams in a tricky section of the river, including at Moody Street in Waltham, where we take out at a kayak rental dock. Despite our accumulated experience, it remains nearly impossible to make a graceful exit from the boat. Sitting low in the water, you need to lift your butt high enough to bridge the narrow gap between boat and salvation. There is a terrifying instant where you are suspended in no man’s land and anything is possible.

On this day, Gene is reminded of that fact. I have clumsily scrambled from the boat onto the safety of the wooden dock and he is starting his own attempt when his boat slides sharply out from under him. The young dock attendant pounces instantly to arrest his descent. Gene goes in up to his waist, but working together, we are able to save him from sinking farther.

He is largely dried out by the time we wrap up, pulling off within sight of Harvard Stadium, where a silver pillar marks the finish line of the Head of the Charles Regatta course. Boston Harbor wasn’t too far now.

Our final day brings us to the broad, picture-postcard section of the Charles River that we all know so well. This is also where the traffic on the river picks up considerably. Boathouses dot the shoreline and rowing teams and clubs pull oars up and down the river. We stay close to the riverbank, out of their way. Approaching the Longfellow Bridge, the duck boats appear.

Planning to end the day in the harbor, we have watched the boating forecast closely; our river kayaks aren’t ideal for ocean waters and we want the flattest seas we can get. Finding the channel adjacent to the Museum of Science and squeezing past another duck boat, we slip under the Zakim Bridge and pause outside the Charles River Dam locks.

Two long blasts, followed by two short blasts on the air horn I had bought online alert the lockmaster to our presence, and, after a minute or two, the doors crank open and we enter. The walls of the narrow lock loom skyward, and when a tour boat carrying sightseers pulls in behind us, our plastic boats feel flimsy and outclassed. We grab the ropes hanging along the sides to keep us from getting knocked around as the water is pumped in to bring us to sea level.

As we exit into the saltwater, a voice over the loudspeaker booms, “Have fun, but watch out for the giant squid!”

We hang a left toward Charlestown and check out Old Ironsides before quickly and carefully crossing the channel back over toward Long Wharf.

After starting back in April and winding our way over countless downed trees, under dozens of bridges across more than 70 miles over nine days, Gene and I complete our quest, pulling our boats out for the final time at Fort Point Pier with a champagne toast and some back-slapping, near the lot where we’d parked one of our cars.

Not long after we entered the harbor that day, a man on shore shouted a question to us: “Where’d you put in?”

“Milford,” I told him. He looked as if he must’ve misheard me.

Gerry Brown is a deputy editor at ESPN, and an alumnus of Boston Latin Academy and Northeastern University. Send comments to magazine@globe.com.

Paddling the length of the Charles River is possible, but careful research and preparation are required.

• The pocket-sized Charles River Canoe and Kayak Guide is indispensable. It has detailed maps and information, including the locations of dams and potential places to begin and end your day on the river.
• Think carefully before paddling the upper stretches of the river; the biggest risks are getting over, under, or around fallen trees in very muddy, slippery, and relatively remote locations. You will get wet and can slip and fall easily.
• Safety is a key consideration. “You should be aware of time of the year and the water temperature,” says Bryce Morris, owner/partner at Paddle Boston, which rents boats from the spring into fall in numerous locations along the river. “We are looking for water temps to be 60 degrees in general, while balancing a few other variables like the air temperature, wind, and time of day.” Always be aware of boat traffic.
• If something does go wrong on the river, have a cellphone handy, ideally in a dry case on your body.
• Massachusetts mandates that you wear a life jacket from September 15 to May 15. Morris recommends wearing it at all times. He also advises to watch for thunderstorms, especially on summer afternoons when they can blow in quickly. In the case of a storm, get to shore, secure your boat, and find shelter.
• Other necessary supplies include water and food, a whistle to call for help, a foldable handsaw for cutting through smaller branches, a headlamp in case you find yourself on the river after dark, and an air horn.