From his seat in the bow of my canoe, Jerry claws frantically at the river. When the current breaks into a gallop, he gives up altogether and rests his paddle across the gunwales (canoeing’s cardinal faux pas), as if our twelve-day trip along Northern Ontario’s Missinaibi River were a ride at an amusement park. Jerry, an affable, middle-aged social worker from Milwaukee, Wisconsin, is counting on me to guide him downriver. I, in turn, am relying on the canoe, made of a durable material called Royalex, to bail us out. “Hey, boss!” Jerry shouts when yet another blunder leaves curls of red plastic on the rocks. “Gimme a quarter pound of shaved Royalex!”

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Since the advent of Royalex in the ’70s, the number of novice paddlers like Jerry has exploded. The vulcanized plastic, with outer layers of vinyl and acrylonitrile butadiene styrene (ABS) sandwiching a foam core, is tough as nails and as slippery as wet moss. While not particularly scratch resistant, it is remarkable for its “memory,” which means the hull can flex over shallows without being damaged. Even a canoe that gets wrapped around a rock will spring back to near-perfect shape after it’s peeled off.

At least a dozen adventure outfitting companies operate in the Subarctic, and many more elsewhere in Canada, almost all using Royalex boats. Few people realize that this product, more than any other innovation, brought canoe expeditions to the masses. “Royalex opened up wilderness tripping,” says Mark Scriver, a long-time guide and outdoor industry sales rep in Dunrobin, Ontario. “It let people beat the hell out of their canoes, and gave them the ability to do things with less skill.”

However, tripping as we know it could soon grind to a halt. PolyOne Corporation, the Ohio multinational that assumed production of the world’s supply of Royalex last year, will shutter its Warsaw, Indiana, factory in April, as part of a larger restructuring to cut $25 million in costs. With annual net revenues of $3 billion, the manufacturer apparently sees little to gain from Royalex. It is used almost exclusively to build canoes, and it only brings in a few million dollars a year, according to Leroy Boser, a former senior sales engineer at Uniroyal, the company that invented the plastic (PolyOne declined multiple interview requests). “They’re not taking any more orders,” says Jacques Chassé, the owner of Quebec manufacturer Canots Esquif, whose designs account for about 20 percent of Royalex canoe sales worldwide. “It’s the end for sure.”

Forty years ago, the bestseller was the aluminum Grumman, a flat-bottomed affair that tended to get stuck on rocks, folding around obstructions like a tortilla. In 1976, Wally Schaber, co-founder of the Ottawa outfitter Trailhead, started guiding trips in the Northwest Territories with a fleet of Grummans. Even though he screened his clients for paddling skills, expeditions were often difficult due to his equipment’s lack of tolerance for human error, but then Royalex changed everything. “We could run big rapids with loaded canoes, and tougher rivers with new clients,” says Schaber. “Only the satellite phone has added as much confidence to outfitting.”

Introduced in 1957 by the United States Rubber Company (later renamed Uniroyal), Royalex combined the rigidity of foam, the durability of ABS, and the UV resistance of vinyl—but there was a problem. “They made this stuff, and then they realized that they had no applications for it,” says Roy Guinn, co-founder of the Tennessee manufacturer Blue Hole Canoe Company. Uniroyal moulded hoods and fenders out of Royalex for tractor trailers until the ’80s, when it became cheaper to do so in fibreglass. The product was also used to build powerboats and replica classic cars, Guinn says, but high production costs meant that canoe manufacturing was the only viable option.

In 1972, Old Town Canoe in Maine became one of the first companies to adopt the current practice of buying raw sheets of Royalex and thermo-forming the boats in-house. The material gained renown seven years later, when an Old Town advertisement showed a seventeen-foot Tripper—“the king of expedition canoes”—surviving a fall from a factory roof. Royalex absorbs impacts that would splinter wood or composites such as fibreglass, making it perfect for whitewater trips and carefree cottage use alike. Kelly McDowell, owner and president of the Complete Paddler, a Toronto retail shop, says 60 percent of his canoe sales are Royalex boats. “The decision to cease production will affect everyone from day trippers to expedition paddlers,” he adds.

The obvious solution—to hoard and stockpile—won’t work, because raw sheets of Royalex have a shelf life of just six months. Manufacturers can’t sock away finished canoes without finding warehouse space for them. “It’s too good of a material to just completely disappear,” insists Scriver. However, PolyOne’s machinery is antiquated and unlikely to change hands.

Paddlers who already own Royalex canoes have little to worry about: my twenty-year-old boat is still going strong. Outfitters will feel the impact sooner; Schaber says the typical lifespan of a rental boat is five years. The outlook is even bleaker for new canoeists, who will be forced to rely on fragile composites, and for manufacturers like Esquif, whose sales depend on Royalex. This year, McDowell plans to load up from the last round of production, and Chassé expects to churn out canoes in huge numbers. Still, no one knows what will happen when the global supply dries up for good.

Back on the Missinaibi, Jerry morphs from passenger to paddler. We have faced struggles—mosquitoes, portages, and plenty of run-ins with rocks—but as we near James Bay, he shows the newfound confidence I’ve observed in countless clients during my fifteen years of guiding. When the river becomes broad and braided, he helps to dance the boat around rocks and combers on the final plunge to tidewater. At the town of Moosonee, we skid the scratched, clay-encrusted canoe into a boxcar and ride the passenger train south, the satisfaction of reaching our destination tempered by the melancholy of a journey’s end.

This appeared in the April 2014 issue.

Conor Mihell Conor Mihell won a gold National Magazine Award in 2012 for his Explore feature “Into the Light.” Alëna Skarina Alëna Skarina counts among her clients the Globe and Mail, the National Post, and Chatelaine.