FOR THE FOUR-DAY VOYAGE to Peel, we'd hired a 45-foot fishing boat, the Capitan Matias, in Punta Arenas, the cosmopolitan southern outpost for travelers heading to Antarctica or Tierra del Fuego. In addition to the captain, Roberto Muñoz, there were two crewmen and Fortaleza Expediciones' Cristian Oyarzo Fierro, a 30-year-old outfitter from Puerto Natales who'd arranged the charter to scout the kayaking around the Monte Pirámide glacier.

"Paine is becoming crowded," Cristian said. He'd started his company when he was 18, in Torres del Paine National Park, but, like everyone else, was finding the place overrun. "So we are looking for areas to guide that are untouched—like where you are going."

Glacier watching involves divining the motives of the heavy clinks and kerchunks to predict that singular moment of cataclysm.

Chilean president Michelle Bachelet's administration, he told us, was offering loans and grants to budding outfitters. "The government likes our idea," he said, "because everything will happen on the boat: stay, cook, toilet, the Internet ... Others want to build hotels and refugios on land, but that's not what we want." His friend the captain was getting in on tourism, too, Cristian said. "Roberto is building a two-masted sailing ship that will hold 20 people, a scaled replica of the ..."—it was on the tip of his tongue—"... the Beagle."

On the bridge, Reg had spread a series of four-by-six photos of Peel's North Arm and Calvo, shot from the space shuttle. Some showed the narrows completely bunged with ice; others showed it looking passable.

"Have people been here?" Reg asked Roberto. I was hoping not.

"Sure," said Roberto, pointing deep into the North Arm. "Abalone hunters." The info didn't seem to bother Reg. He didn't want the bragging rights; he just wanted to see the historic fjord.

Three hundred miles later, on a typically overcast February day, we watched as the Capitan Matias motored out of a natural lagoon 30 miles seaward of Tilman Island, and we were alone. I've kayaked plenty of rivers, but this was my first go in the ocean. A month's worth of gear feels like a heavy plaster cast in the cockpit, but the suffering was for good reason—namely, ten avocados, three pounds of Peet's Coffee, four wheels of Dutch cheese, several gallons of Carménère, and a number of other necessities, like my cushy camp chair, a pair of Reg's patented drip-filter-and-coffee-cup-in-one BrewMugs, and a sat phone for calling girls.

On land, Reg looks like your average wild-haired, six-foot retiree, but in a boat his lanky arms and thick trunk coordinate strong, smooth strokes. Following him is like trying to match strides with a pro basketball player.

We camped that first night at a rocky point near a 500-foot waterfall. After unpacking, Reg easily shouldered his half-empty kayak, still close to 200 pounds, up to the calafate bushes, tied it against the wind, and then helped me do the same. We cooked freeze-dried lasagna on the 20-year-old alcohol stove Reg swears by, and in the morning I heated water for coffee while Reg checked the barometer and repeated his mantra: "Only a fool tries to predict the weather in Patagonia." If it was stormy, we stayed put; if not, we kayaked. This would become our routine.

On our second day in the boats, Reg unfurled a large blue-and-yellow golf umbrella, caught the wind, and went sailing off ahead of me like Mary Poppins, actually giggling. Then—sprong!—the ribs inverted, and I was the one laughing. Soon I was a convert.

Later that day we reached the narrows, the gateway to the North Arm. It's more than a football field wide, and even with the tide against us—with swirls and boils and refrigerator-size blocks of ice clacking in the outgoing tumult—it wasn't until we'd eddy-hopped up it and were staring at an honest-to-God rainbow spanning the entire fjord like a bridge that we realized we'd made it into the North Arm. "Not a bad welcome," said Reg.

The ice wasn't quite clogging the choke, but it could with a change in the weather. For two days we watched the bergy bits flow with the tides, and when Reg was satisfied that the ice-in/ice-out pattern was stable, we packed a week's worth of food and fuel, stashed the rest, and headed in.

Of the ten floes Tilman described, three in the North Arm reach the water: Lobos, Patos, and Garcia. We spent an entire day glacier watching from our camp high on the bare granite shoulder of Lobos's southern moraine. The gray scar of once covered rock is visual confirmation that Patos, like many of Chile's glaciers, has lost about 6 percent of its ice over the last 20 years. (The Alps have melted by as much as 35 percent.) Had the Mischief made it into the North Arm, Tilman would likely have seen only ice. But now the glacier meets the bay half a mile back.

Most of the time, glacier watching involves divining the motives of the heavy clinks and kerchunks—like the coupling of faraway railroad cars—trying to predict that singular moment of explosive cataclysm. Then it happens with a puff of white followed by a rumbling report that makes it clear the puff was actually on the scale of a six-story building imploding.

On our third afternoon in the North Arm, we reached Peel's farthest point inland, a granite promontory protruding from the calafate. A mile above us was the treacherous Falla Reichert Pass that Norwegian adventurer Børge Ousland and Swiss photographer Thomas Ulrich had to cross on their historic unsupported traverse of the southern ice cap in 2003. On top of the promontory sits a cairn with a simple plaque left by Chilean commandos in 1997 as a memorial to a fellow soldier. How they got there, we don't know. But if they chose the spot because it's beautiful, spare, and hard to reach, they did well.