Then the W.S.L. announced that the California leg of its 2018 Championship Tour would not be taking place at its longtime locale, a point break in Orange County called Lower Trestles; instead, the main California event would be held at Surf Ranch. This was controversial, even among the pros, some of whom felt that Slater would enjoy a home-court advantage. Beyond that, what would it mean to shift competition from the ocean, where so much of the game turns on reading waves wisely, to a tank where a machine spits out identical waves on a timetable? The Surf Ranch Pro was scheduled for early September, and Surfline, a popular surf-forecasting Web site, cheekily added Lemoore to its list of spots. The waves there, it said, would be “good to epic” every day in September, and pretty much the same every day thereafter.

I arrived on the first day of the maiden Surf Ranch Pro. The early rounds of the contest were in progress, but there was no really good place from which to watch the surfing. The pool is seven hundred yards long, perhaps a hundred across, and the wave runs both north and south, so at least half the time you’re looking at the back of a wave. Often, live viewers were reduced to watching one of several jumbo screens erected above the eastern wall of the pool. We could hear bits of the Webcast commentary: “Carissa . . . power gouge to set up the pit.” Slater was already leading the men. The big screens filled the long minutes between waves with highlight replays and commercials for Jeep and Michelob and Hurley.

I found the replays deeply confusing. A slow-motion closeup of a great surfer like Carissa Moore tucking into a spiralling barrel was mesmerizing, but not because of what Moore was doing—she was, after all, invisibly deep for most of the clip. Instead, I found myself bug-eyed, forgetting to breathe, silently shouting, “Look at that wave!” The relentless precision of the spilling lip was the news. It was a once-in-a-lifetime wave. Of course, I was being absurd. Every wave here did that.

Adam Fincham saw it differently. “We’re looking for any small discrepancies,” he said, as he studied a breaking wave. Fincham, fifty-two, is a research associate professor of aerospace and mechanical engineering at the University of Southern California, specializing in geophysical fluid dynamics. He was the one who took up the gauntlet when Slater, in 2006, came looking for help with his artificial wave. He had no idea who Kelly Slater was, but he enjoyed a challenge and recognized a fellow-obsessive.

Fincham, who was born in Britain and grew up in Jamaica, envisioned a soliton—a solitary wave that maintains its energy as it propagates. The phenomenon was first described in 1834, by J. S. Russell, a Scottish civil engineer and shipbuilder. It seemed to contradict the reigning understanding of wave-water physics, but its existence was mathematically explained a few decades later. Solitons are now significant in a number of fields, including neurology and fibre optics. But no one had created a soliton in water on the scale that Slater wanted. “It was a big ask,” Fincham recalled.

Working with other scientists from U.S.C., the two men built a prototype wave tank, modelling the long, powerful, immaculate wave that Slater imagined. They went down many blind alleys. Fincham designed a system in which water rushed over a stationary hydrofoil, but it did not produce the desired result. They tried a moving foil, pulled through the deepest part of the water. That was more like it. Getting the wave to break, symmetrically and hard, with a face curved in an ideal shape for surfing, was a problem of another order. They studied great ocean waves, broke them down into millions of separate components—tiny cells of water and air, all interacting in a field of daunting nonlinearity—and then tried to rebuild them in the lab. For these simulations, bathymetry—the exact shape of the bottom of the pool—was critical, and the scientists ran models on parallel supercomputers for weeks at a time. The work was “mathematically horrendous,” one of Fincham’s colleagues at U.S.C. told Science.

By 2013, the team was ready to take the experiment outdoors. Slater quietly bought the property near Lemoore, which included a long, narrow artificial lake. Construction and testing proceeded under a thick blanket of secrecy. When workers went into town, they wore monogrammed shirts (“Fish Pond, LLC”) and said that the place was going to be a fancy tilapia hatchery. There were, at one point, as many as three hundred employees. To advise on the construction, Fincham brought in experts from the mining industry. “They’re dealing with big, powerful machines that have to work,” he told me. “You know, if your gold mine goes down for a day, that’s a lot of money.”

What you see now, looking eastward across the pool, is a Mad Max-esque contraption known in-house as the Vehicle, whizzing back and forth on a raised track on a hundred and fifty or so truck tires. The Vehicle is about the size of three train cars, and looks from a distance like a tattered blue houseboat tipped up at an angle. It is unmanned and travels, hauled by heavy cables, between two big winch houses at either end of the pool. The most important part of the Vehicle is a hundred-ton iron blade, roughly a hundred and fifty feet long, that hangs half submerged from its western side. Beneath the pool’s opaque surface, this iron sheet becomes the hydrofoil, able to push huge amounts of water at extremely finely calibrated speeds and angles.

The exact shape and dimensions of the Surf Ranch hydrofoil are a trade secret. Whatever its particulars, it is nothing like the hydrofoils under the hulls of high-speed racing sailboats, which lift them above the water’s surface. “This was like I was trying to design the worst possible sailboat hull—the slowest, most uncontrollable,” Fincham told me. He chortled, but he did not stop peering across the water, assessing the waves and the state of the pool during the three minutes that it was left to settle between waves. His phone buzzed. His team was apparently seeing discrepancies. “That was the wind, I think,” he told someone. The foil beneath the Vehicle can run at different angles and at different speeds, to create different types of waves. For this competition, all the waves were supposed to be exactly the same, but that could require tweaks as conditions changed. Fincham gave mumbled instructions to staff members in a control tower, near the midpoint of the pool. Perfection was a work in progress.

The idea of the perfect wave has been around surfing since I was a kid. “The Endless Summer,” a documentary by Bruce Brown, released in 1966, follows two California surfers circling the globe with boards. They find “the perfect wave” in South Africa, at Cape St. Francis. The holy grail in this case was a small, groomed, exquisite wave, peeling just off the rocks, and Brown assured us that, according to local fishermen, it broke like that three hundred days a year. In fact, it seemed to break like that for the ninety minutes that Brown was filming, and then the tide came up, or the wind shifted; waves of that quality have never again been seen at Cape St. Francis. Breaking waves in the ocean are fleeting, complex events, each one unique. There are great surf spots, to be sure, but there is no such thing in nature as a perfect wave. My dream wave, moreover, will not be the same as the next guy’s, or the same as Kelly Slater’s. (I’ve heard Slater rhapsodize about a certain day at a certain reef break in Barbados. Photographs from that day suggest that neither I nor the next guy would have dared to leave the beach.)