THIRTEEN
IN FEBRUARY 1991, STONE LED HIS first expedition down to Cheve. Co-led, actually, with two other elite American cavers, Don Coons and Matt Oliphant, although, as one who was there noted, there were three leaders, but there was really just one Leader. Sadly, the rebreather was still not ready for cave diving, so to penetrate the terminal sump that had prevented all further progress, they once again hauled scuba tanks and gear, lead weights, and 2,000 feet of safety line all the way down to Camp 3.
From there, they carried everything another third of a mile and 470 vertical feet down to the Cheve terminal sump. On March 1, a man named John Schweyen, then one of the best American cave divers, geared up and slid into the 54-degree water that looked clear and turquoise under the cavers’ lights. There was almost no flow and very little silt to reduce the visibility, which, for a sump, was excellent: 20 to 30 feet. The sump floor was coarse tan and brown gravel. Schweyen started swimming, playing out safety line, following the sump as it descended at 45 degrees until leveling out at a depth of 75 feet. Remaining at about that depth, he continued on horizontally for another 300 feet, then came to a porthole-sized opening that he could see beyond but could not pass through. Schweyen returned safely from what had been a relatively benign dive.
Two scuba tanks were left, but during the descent a valve had been knocked open on one, causing it to lose half its air. This demonstrated once again how inadequate standard scuba was for supercaving; they could not dive the sump safely with one tank and a half-full backup. Well before the team reached the surface, though, it became clear that neither Schweyen nor anyone else would dive again, because on their ascent they found the note about Chris Yeager’s death, which ended everything for 1991.
IN 1993, TWO EXPEDITIONS, NEITHER LED by Stone, tried pushing Cheve, using every trick in their books to pass the terminal sump, digging and climbing, crawling and swimming. Every trick except diving, that is, because the expeditions were led by Matt Oliphant and a great caver named Nancy Pistole, and neither were cave divers. They tried, instead, to discover a dry way around the sump. They did find about a mile of new passage, but it did not take them beyond the impeding sump.
Still focused on perfecting his rebreather, which he believed was the key to supercave exploration’s future, Stone viewed these efforts from afar, not especially troubled by them. The terminal sump, he felt strongly, would not be cracked with conventional scuba. The extensive underwater investigation required to find a passage out of the sizable sump could be done only with a rebreather. And no one else was developing a rebreather specifically for cave diving. In other words, he held the only key that could unlock that sump—it was just a matter of making final adjustments to that key.
But even for all that, he had never lost sight of Huautla. Cheve took over his life from 1988 to 1991, true, but partly because his rebreather was not ready to tackle the San Agustín Sump. The U.S. Navy’s debacle aside, had Stone been able to work on his rebreather full-time and without financial constraints, it’s entirely possible he could have produced a workable, expedition-quality rebreather in two or three years. But he did not have those luxuries, and so the project stretched on and on.
It was not the only thing being stretched—so was Pat Stone’s patience. If Cheve had consumed her husband’s life for four years, from 1988 to 1991, as he himself has remarked, the rebreather project had done much the same thing for the four years preceding 1988. It would do so again in the two years after 1991. That made a decade. By 1991, the Stone family included three young sons, and the focus of Pat Stone’s life had naturally shifted from caves to kids. It was not unreasonable to expect a similar change in her husband. As the years passed, though, it became increasingly clear that such a change was not in the offing. With each departed year, Pat’s hopes for a traditional family life grew dimmer.
Stone’s hopes for the rebreather, on the other hand, were steadily brightening. So much so, in fact, that in 1992 he began planning his most ambitious expedition to date, a 1994 assault on Huautla with a million-dollar budget, scores of sponsors, a cast of dozens, and his rebreather as the star attraction. Now into its third generation and called the MK-III, it was not fully expedition-ready in 1992, but Stone felt confident that two more years of testing, followed by intensive diver training, would make it so. He would need that much time, in any case, to line up sponsors, secure Mexican permissions, recruit team members, and attend to the thousand other details such an expedition requires. Bill Stone, finally, was seeing light at the end of his ten-year tunnel.
The rebreather’s path to fruition had not been without some frightening setbacks. In late 1989, a diver named Brad Pecel repeatedly tested Stone’s second-generation rebreather, the MK-II, in Florida. On one particular dive, Stone came along as Pecel’s buddy. Not twenty minutes after entering the water, Stone watched, stunned, as Pecel started convulsing. On the surface, the violent jerks and spasms of convulsions are terrifying. Deep underwater, where they almost always include spitting out the breathing mouthpiece, they reach a whole new level of horror. Stone followed standard scuba diving rescue procedure, putting a backup regulator into Pecel’s mouth and bringing him to the surface as quickly as safety allowed.
Pecel, far luckier than most divers who convulse at depth, survived. But the incident revealed something unsettling: redundancy was a two-edged sword. Like FRED, the MK-II had two completely independent systems. Pecel’s support team had prepared his rebreather incorrectly, plugging the oxygen display panel into the wrong system—the one not being used actively. The rebreather then delivered improperly mixed breathing gas to Pecel underwater, resulting in an overload of oxygen in his system. Oxygen toxicity, a familiar diving hazard, causes convulsions.
When he understood that the MK-II rebreather’s complexity was the root cause of his accident, at least as he viewed it, Pecel would have nothing more to do with the unit and summarily quit. The other divers did not quit, but the incident left them with concerns. Word got around about the high-tech, complicated units, and rumors circulated that a rebreather malfunction had almost killed a diver. That was only part of the story, but it seemed to be the part that stuck in people’s minds.
The passage of time might have allayed many of the concerns, but the next decade turned out to be a deadly one for Bill Stone and his teams.