Ned DeLoach
First published in Ocean Realm #2, Summer 1988
At the sound of the last bell on Friday afternoon, April 1, 1988, Sheck Exley locked the door to his classroom at Suwannee High in Live Oak, Florida, where he teaches algebra. It was the beginning of Spring Break. He signed out, joked briefly with a few students gathered at the school's entrance, and walked across the parking lot to his red Ford van. The chassis was sitting unusually low. Sheck knelt down to inspect the rear tires.
He made a mental note to inflate them even more. Causing pressure on the tires was the weight of thirty-four scuba tanks packed carefully inside. Each cylinder was filled to capacity with gas mixtures--helium, oxygen, and compressed air. The sizeable collection of tanks, enough to supply the average needs of a sport diver for a lifetime, would be required for Sheck to make a single exploratory dive into Nacimiento Del Rio Mante.
Mante is a water-filled spring cave located in northern Mexico, west from Tampico, across a fertile plain that runs inland from the Gulf of Mexico for sixty miles. The flat land ends abruptly just past the farming community of Ciudad Mante, where an ancient geological fault split the earth and pushed the continent straight up over 2,000 feet. Flowing mysteriously from the mountain's base is a clear river. The cool water streams from a dark cave entrance, briefly forming a spring pool that quickly narrows and begins to wind its way east across the arid farm land.
The river is a welcomed anomaly where rain is scarce and the tropical sun unrelenting. From the early Indians until today, the local inhabitants have gathered in the basin's pleasant surroundings. They wash in the cool, sweet water that is shaded by the cliff above. Tall flowering trees line the water's edge. Fragrant blossoms--purple, gold, and white--shower down on the bathers below. Where the river comes from, no one knows. "From the other side of the mountain," you will be told, with a shrug, if you ask.
Unlike the bathers who relax daily in the spring's outflow, Sheck knew well the hidden river's path. He had made four previous dives into the mountain cave starting in 1979, and he was leaving that afternoon to make another.
On his first trip, Sheck and veteran cave diver Paul Deloach penetrated 150 feet into Mante's cave opening, where they located the cavern's true course--a narrow fissure that dropped directly down the great fault.
"We had dived several other Mexican spring caves before we arrived at Mante," Sheck recalled. "Most began with a steep drop, but would form into a horizontal tunnel at a depth between 140 and 190 feet. Mante was different; it just kept dropping beneath us. Although the crevice was over 100 feet long, it was quite narrow, just over three feet in places. The current was difficult. Enough water was shooting up the passage to feed a river that runs for miles. Moving against it was like swimming up a waterfall. We used our hands to pull on the sharp rock walls. Both of us were pretty cut up after the dive." Three hundred thirty feet below the surface, the divers stopped, hovering on the very edge of their physical limits. Below, Mante continued its plunge into darkness.
"At our turnaround point I remember thinking about Sotano de los Golondrinas, the world's deepest free-falling pit that was just sixty miles south of us. Its drop is 1,248 feet. Could Mante be this deep? It was exciting to think that we might be suspended inside the deepest underwater cave in the world." Both divers knew to venture no further. In the deep passage, their minds were already swirling with vertigo that would intensify with depth until reality blurs into unconsciousness. Sheck tied the safety line to a rock projection and began to ascend. The return to the surface would be slow--over an hour. Long, tedious decompression was the price they paid for going deep.
Two of the world's most experienced deep-water cave divers had once again been turned away by the "depth barrier"--a set of physiological hazards that had taunted them for over a decade. The hazards combined to make deep diving a risky business below 130 feet, and past 300 feet almost suicidal. It was clear: if Mante's secrets were to be discovered, technology would have to advance to a point where narcosis could be suppressed and decompression time shortened. Less than a decade later Sheck would explore far beyond the "barrier" on a dive that would establish Mante as the deepest water cave in the Western Hemisphere and, in doing so, he would set a depth record so extraordinary that it was unimaginable in 1979.
After his reconnaissance trip to north Mexico's caves, Sheck returned to Florida where he continued to lead the way in the exploration, surveying, and mapping of the state's extensive aquifer system--an obsession that has directed his life since he became certified in scuba, in 1965, at the age of sixteen. He made his first open-water dive in a shallow spring cave in Florida's Crystal River. Although the limestone opening offered limited penetration, it was enough to ignite an insatiable curiosity that would, in only a few years, propel Sheck to the forefront of underwater exploration. In less than seven years, at the age of twenty-three, he became the first person to log 1,000 cave dives. This was an average of two and a half cave dives per week. During the same period he graduated from high school and the University of Georgia in Athens, a 600-mile round trip from the North Florida spring caves. In May 1987, his 3,000th cave dive was entered in his log.
Sheck not only leads the way in the caves, but also in cave-diving education. An untiring effort has produced over 100 articles and six books on the subject. He has been repeatedly honored for his accomplishments. These distinctions include being named a Fellow of the National Speleological Society and Explorer's Club and, in 1981, receiving the Lew Bicking Award as America's top cave explorer.
Although Sheck is proud of these honors, they are not a compelling force behind what he does. He is an inherent explorer whose true passion is to go where no one has gone. Our planet's last unmeasured frontier--the earth's depths--is the realm he has chosen to enter. This compulsion has for twenty-three years repeatedly driven him further and deeper into water caverns than anyone has gone before. At thirty-nine he remains a forerunner with visions yet to conquer.
"Thirty-nine is old for pushing physiological limits in underwater caves. Marathon runners tell you that your respiratory efficiency, critical on a deep dive, drops enormously as you reach the midthirties, and the risk of bends rapidly increases with age after thirty. I still feel well-prepared, mentally and physically, but I am constantly aware of my age. I must always factor it into my dive plans.
"Nine years ago, when I first dived Mante, I was at a physical peak, but it didn't matter because we hadn't yet gained the know-how to go deeper. I remember looking at the cave dropping below us into unattainable depths--it might as well have been a painting. Underwater cave exploration is a technologically dependent endeavor, and we were then locked out by numerous constraints. I had no idea then if I would ever be able to explore Mante further and even less idea from what direction new technology would come to make it possible."
As it turned out, it was a combination of three elements--oxygen, helium, and computerized decompression tables incorporating these gasses--that would key new possibilities.
In the early seventies, cave divers took a lead from the US Navy and began to experiment with oxygen. Its use helped to shorten the long decompression required after lengthy cave penetrations. Breathing from tanks filled with pure oxygen at the ten- and twenty-foot intervals could cut decompression time by as much as half. Like everything associated with deep diving, however, the innovation was not without risk. It was quickly learned that if too much oxygen was breathed below thirty-three feet, a deadly condition called oxygen toxicity (oxygen poisoning) developed. Symptoms are extreme--sudden convulsions, then death. To complicate things ever further, the navy's oxygen tables were based on experiments conducted with unexerted subjects locked out in dry chambers. When cave divers applied the navy's times to their stressful environment, problems developed. Sheck cared even less for the long decompress periods than most cave divers.
"Five or six hours spent hanging off in the cool water of a spring basin was a numbing conclusion to long and difficult exploratory dives," he explained. "The sheer boredom was grueling. We used to read, play magnetic checkers or pull tricks on each other; but generally we would put ourselves into a trance. Oxygen was a great help. It was the closest thing to a decompression pill we found."
Early experimentation by the navy found that the substitution of helium for nitrogen in underwater-breathing mixtures greatly reduced narcosis The ability to dive deep and remain clearheaded would be a dramatic breakthrough for cave explorers, but problems complicated early trials. The navy spent a great deal of time trying to devise safe helium tables but were thwarted by the gas's volatile nature. Decompression times proving safe for one diver would cause severe cases of the bends in others. Helium also caused a rapid reduction of body heat, bringing about hvpothermia. On top of these problems, when breathed at great depths, it played havoc with the diver's nervous system. Sheck doubted that the gas would ever have any serious application in cave exploration. The few divers that did use helium met with mixed results, often tragedy.
The helium horror stories started in 1970 when Hal Watts, a pioneer deep diver from Orlando, Florida, used a helium mixture during a body recovery at Mystery Sink. The navy declined to take part in the search but recommended a heliox (helium/oxygen) mixture for the difficult dive. Hal remembers being cold and nervous as he dropped into the lower reaches of the sinkhole. Failing to find the lost diver, he headed toward the surface. During ascent, problems occurred, forcing Hal to miss his sixty-foot decompression stop. He sustained a severe bends hit.
"The pain felt like my lower spine had been injected with hot lead. I agonized and vomited constantly for the two and a half hours it took to get me to a chamber at the Cape," Hal vividly recalled. It was a year before he completely recovered from the painful injury.
Sheck's closest friend, Lewis Holtzindorff, died in 1975 while attempting the world's first cave dive using helium. The divers were decompressing on oxygen at forty feet after a dive of 265 feet Both were suddenly unable to breathe. Lewis convulsed and drowned; his partner, Court Smith, miraculously made it to the surface and survived.
During 1978, two divers reached 325 feet in a Missouri cave. They were experimenting with trimix (helium/oxygen/ nitrogen). Although only 50 percent of their mixture was helium, both became hypothermic and had great difficulty finishing their required decompression. Sheck followed these stories carefully, remaining unimpressed with helium's potential. He had gone deeper in caves using compressed air. Why should he be concerned with helium?
American cave diver Dale Sweet finally made a successful breakthrough with mixed gasses in 1980. Using heliox, he bottomed out the west Florida sink Die Polder #2 at 360 feet. Dale's dive had broken Sheck's deep cave dive record by twenty feet. His achievement immediately got Sheck's attention. Six months later Sheck made the same dive using air. Matter settled!
The big bombshell came from across the Atlantic in 1981. Europe's best underwater cave explorer, Germany's Jochen Hasenmayer, descended into the French Vaucluse to 476 feet. Everyone was stunned. Not only had he shattered Sheck's cave record by over 100 feet, but he had also set a new world's record for a surface-to-surface dive on scuba. Jochen was breathing heliox.
Sheck was busy setting records of his own when word of Jochen's extraordinary feat reached Florida. The team of Sheck, Clark Pitcairn, and Mary Ellen Eckhoff were making final preparations for a big push into the Big Dismal cave system. In June, the trio penetrated the underwater cavern 5,847 feet. A month later, Sheck, Clark, and Bill Main made an incredible seven-stage-bottle foray into Manatee Springs. The effort produced, and remains today, the world's record swimming cave penetration of 7,665 feet.
When Sheck finally stopped long enough to contemplate Jochen's record, he still remained skeptical about the use of helium in cave exploration. "Both Jochen and Dale made impressive dives, but I felt that they were riding on luck. I wouldn't give either of them odds to safely repeat the dives."
Two years later, in 1983, Jochen made another deep dive. The result--an astounding 656-foot plunge. Again, he was using heliox. With this one dive, the "barrier" that had been firmly in place for over a dozen years was swept away. Rules had been changed. A new era had begun. Matter settled!
The use of the navy's decompression tables to prevent decompression sickness (bends) has been standard procedure for scuba divers since the sport began. These tables, however, are not applicable when breathing mixtures are changed from air (21 percent oxygen/79 percent nitrogen). With the advent of saturation diving from deep-water habitats in the 1960s, the perplexing search for reliable mixed gas tables for surface-to-surface diving came to a standstill Recently, cave divers had begun to challenge the deep caves. Their venture has many obstacles. The most pressing is safe decompression.
The 1987 Wakulla Spring Project, headed by Dr. Bill Stone, combined the latest in diving technology to explore one of Florida's largest and deepest cave systems. The twelve project divers, including Sheck, penetrated over 4,000 feet into the passages at depths to 300 feet using mixed gas, a historic milestone in cave exploration.
During the intensive diving, not one explorer had problems with the bends. The tables used at Wakulla came from a new source--DECAP (Decompression Computation and Analysis Program), a creative computer program operated by Bill Hamilton and Dave Kenyon from Tarrytown, New York. Sheck was impressed; this was the break he had been waiting for to get deeper into Mante.
After leaving Suwannee High School, Sheck drove to his home located a few miles outside Live Oak. He had purchased this particular piece of land a few years back because less than 200 feet behind his backdoor a sinkhole opened into the world's largest aquifer system. I was sitting on the front porch of his double-wide, surrounded by cameras and scuba equipment, when the van pulled through the gate. A loud greeting preceded Sheck out of the van. "Tapeizcuinte, que pasa?"
He tagged me with this outlandish nickname during a reconnaissance trip we made to the Yucatan coastal caves in the seventies. Short on cash and civilization, we found ourselves eating from a limited wildlife menu at a cheap Mayan restaurant located just off the Xcaret road. The bill of fare consisted of lobster, grouper, venison, and tepeizcuinte.
"Que es tepeizcuinte?" Sheck asked the young boy waiting the table. From what could be deciphered from his mumbled answer, we gathered that it was a small animal hunted in the jungle. In a moment of daring, we both ordered tepeizcuinte and Pepsi. Although the exotic entree had been disguised by preparation and cooking, our servings suspiciously resembled skinned wharf rat done to perfection and served in a green mole sauce, except that on the ends of their small, muscular legs were sets of tiny hoofs.
Smiling, Sheck came up to the porch and we shook hands. I followed him into his darkened living room where I almost tripped over a five-foot Aquazepp underwater propulsion scooter that dominated the center position in a room filled with charts, files, books, and an assortment of unmarried-man clutter. In the kitchen, he shoved papers aside, sat down, and began to intently study a neatly spaced, three-column list he had taken from his pocket. Each item represented a vital link necessary for the completion of the most daring and logistically complicated scuba dive ever attempted. After nine months of planning, nothing was going to be forgotten in a last-minute rush to leave town.
I left him at the table and began to load my gear between the stacks of tanks roped tightly together inside the van. Ten minutes later, Sheck emerged carrying a paper sack of groceries.
"Ahout ready?"
"Sure," I replied. Less than five minutes later we were heading west on 1-10.
Our long drive to Mante would take us nearly 1,500 miles--across the southeastern states, through Houston, down to the Rio Grande Valley where we would cross the border at Brownsville, and then 300 miles on into Mexico. I had not seen much of Sheck for the last few years. A cave-diving photography project in Yucatan had occupied my last two summers, while Sheck had been busily involved with his deep-cave diving and whitewater kayaking. During the Wakulla Project, I spoke to him briefly; the next month we shot some cave-diving pictures for his autobiography, to be published next year. I had heard about his big dives at Mante, but knew few details.
Sheck called to ask if I would go with him to Mexico only three weeks before we were scheduled to leave. I said yes, thinking that the expedition south would involve a substantial support group. It wasn't until the week we left that I realized it was just the two of us driving down. We were to meet Mexican cave divers Sergio Zambrano and Angel Soto at Mante. They were driving north from Mexico City to make the rendezvous. Both were exceptional cave divers, but I realized that neither had the experience to help Sheck if an emergency occurred.
It was only at this point that I started to comprehend the intricate web of problems that would face Sheck There was no support for such a dive, absolutely none. Not the navy, not commercial diving companies, not even the cave diving elite could be of the least assistance where he was going. Sheck would be a one-man show heading straight for no-man's land, where submersibles and diving bells couldn't go. If something were to happen, the show would be over--no rescue, not even a body recovery would be possible.
As we drove past Tallahassee and headed toward Pensacola, Sheck began to tell me about the dive. "After Jochen Hasenmayer's dive to 656 feet, I knew that helium was obviously the way to go. In late 1986 I made two practice dives on helium in Florida. The first was to 130 feet, the second was a 260-footer. Last April, Mary Ellen (Eckhoff) and I left for Mexico. After eight years I was more than ready to extend the line deeper into the Mante system.
"Two days before the dive, we staged five tanks in the cave. I wasn't sure how deep I would go. I had decompression tables for 400 feet and extrapolations for even greater depths. My depth gauge was good to 500 feet. As it turned out, everything went well and I tied off when the gauge read 500 feet. Since they are calibrated for denser sea water; that meant 515 feet at Mante and my feet were five feet deeper, so 520 feet. Over seven hours and twenty-six decompression stops later I surfaced. Nothing to it," he laughed.
"What made you decide to go back after the 520 dive? Was in Hasenmyer's record?"
"Yeah, it was the record, but besides that, Mante was still dropping and I wanted to be the one to bottom it out.
"Mary Ellen and I went back in June, just two months later. I had made a few alterations in my decompression to help alleviate the oxygen toxicity symptoms--muscular twitching in my face and legs and slight tunnel vision--I experienced during my previous dive. This time I used less oxygen and two additional shallow water decom stops were added.
"It took me twenty-four minutes to drop 660 feet. Everything worked well, but it cost me eleven and one half hours of decompression time. Over twelve hours is too long to remain underwater. I became extremely uncomfortable--cold, weak, and hypoglycemic from the predive liquid diet. My exposed hands and face became wrinkled, raw, and began to flake. At the time I felt that I could have dived deeper but I knew that I had reached my decompression limits."
"You said you reached 660 feet. It sounds like you went just deep enough to beat Hasenmayer's record."
"No, not at all," Sheck replied. "The best way to end up dead on a deep dive is to go after a set number. First, you have to understand that I didn't know how deep I was after I left my depth gauges at 515 feet. To figure my depth, I connected a premeasured line to my previous line. At the deepest point I tied off and cut the strand. After I surfaced, it was a simple matter to calculate my depth from the remaining length. When I decided to turn around I had no idea if I was above or below Hasenmayer's depth. As it turned out, I was so close to his mark that I didn't claim the record."
"So now you're headed back?" I asked.
"Yeah, so now I'm headed back," he repeated
With that, we silently settled into the ride. Sheck slid a cassette into the deck, and soon we were absorbed in the sounds of his beloved Beethoven. We were 350 miles into the trip, just west of Mobile, when we switched places. I climbed behind the wheel and Sheck stretched out in the reclining passenger seat. A light rain began to fall. I glanced over at Sheck. He was resting with his hands behind his head. Since our earlier conversation we hadn't talked about the dive, but I couldn't get it out of my mind. Sheck would soon be asleep; this would be the last chance until morning to ask questions. "How deep do you think you'll be able to go on this trip?" I asked, suddenly.
Sheck didn't answer for a while. Then just as abruptly as I had asked the question, he answered, "At least 700 feet, maybe more." Again silence. I waited but he didn't continue.
I tried again. "What about decompression?"
"I'm using new tables," he replied. It was obvious that he would rather be with his own thoughts than in conversation, but I chose to persist.
"Whose tables are they?"
With this Sheck relented and sat up, adjusting the seat to support his back "Bill Hamilton's, the fellow from New York who did all the tables for the Wakulla Project."
"Have they ever been tested as deep as you're planning to go?"
"Of course not. Who would test them?" he answered, tersely.
"Hasenmayer," I retorted. Sheck broke into laughter. He was ready to talk.
"I was maxed-out on decompression during the 660 dive. When I finally got out of the water, I was wasted. I knew then that I would have to come up with a shorter schedule before I went deeper, and besides, I was losing confidence in the tables I used for my four previous dives. They were based on purloined commercial tables that I extrapolated to the point that I was concerned about their validity.
"Hamilton's DECAP program was not only more liberal than the tables I had been using, but it allowed me to custom-tailor my gas blend. The few cave divers who are now using mixed gases are abandoning nitrogen altogether. My body seems to have a high nitrogen tolerance so I choose to use trimix during the deepest part of my dive, hoping that this will help me avoid helium's high pressure nervous system syndrome and hypothermia.
"Using the computerized tables for this dive will require that I stage sixteen bottles and carry four tanks. Eleven different blends will be used. I will make fifty-two decompression stops, starting at 520 feet and ending with a half hour at the surface breathing oxygen. How long the stops take will depend on the descent time, maximum depth, and how quickly I can get up from the deep water. The last variables can't be plugged in until I actually make the dive."
I glanced over at Sheck. He was again lost in thought, staring blankly into the night. It had been fascinating listening to him discuss the facts and figures of the dive, but what I really wanted to hear about were the things that go on inside his head when he's buried under several hundred feet of water, inside a rock crevice, on the very edge of life, and still going down.
"How are you going to decide when you've gone deep enough?" I asked.
"Fear." Sheck answered immediately, as if he had been waiting patiently for such a question.
"It's a mind game. The cave and the odds are out to get me and it is obvious that they will catch up with me sometime. That I am alive today is a miracle. To extend my winning streak I must spend hundreds of hours thinking of every possible thing that can go wrong. I do what I can to prevent problems during my dive preparations. I mix my own gases, I check every piece of equipment over and over, and I memorize each aspect of the dive plan. The dive itself is like hunting a tiger in a thicket. Fear keeps me alert. I am constantly attuned to every feeling in my body, every function of my equipment, and every happening in the surroundings. Off guard for a minute and the tiger is on my back.
"I've learned to handle the fear by what I call controlled paranoia--a combination of meditation and experience. The meditation clears and settles my mind, allowing me to stay at a high state of alertness and be continually aware of my body's reaction to the stress. My experience has taught me how vulnerable I am.
"During my twenty-three years of cave diving, I've survived every life-threatening situation: bends, panicked buddy, being lost, silt-outs, light failures, being out of air, line entanglement, being trapped in restrictions, on and on. When something goes wrong, I must immediately rein in the fear and let experience take over. Problems can occur, but an error in judgment is deadly.
"From the dive's start, the idea is to get down as fast as possible without plummeting out of control. I use gravity and pull on the wall to keep from using my legs, which will increase my exertion. While dropping in the deepest part of the shaft I'm in a high-risk zone. At such depths each breath causes the pressure gauge needle to drop unbelievably. Like a pilot constantly picking out alternate landing sites for emergencies, I'm always looking for a projection to tie off. If anything goes wrong, my experience takes over. The problem must be solved on the first attempt or I immediately abort the dive. If the dive goes as planned, the turnaround point will be dictated by my down time, the amount of gas expended and an indefinable coalition of sensory perceptions that tells me to get the hell out."
After finishing the statement, Sheck then wished me good night and crawled across equipment to the back of the van where he had constructed a platform bed over the tank storage. To save time, we had planned to drive straight through to Mexico. I was to drive the night shift so that Sheck wouldn't have to alter his regular sleeping habits before the dive. A mellow, sensuous sax from a New Orleans all-night station kept me company through Louisiana and into Texas. We streaked through Houston at 4:00 AM and were ready to head south toward the border when he crawled hack to the front.
"How about breakfast, amigo, or do you want to drive a bit further?" he joked. We pulled into the first diner I saw. My body was still on autopilot and buzzing from fatigue after the eight-hour ordeal. Sheck was making an issue of how well he had slept as we walked into the restaurant lobby where a set of brightly lit arcade games glittered against the wall.
"Hey, amigo, just the thing for you." He stepped over to a machine and dropped a quarter in the slot. An animated race car leaped into action, careening from side to side at a dizzying pace down an endless highway. As I stumbled into the dining room, heading for the first vacant booth, I could still hear echoes of Sheck's laughter coming from the lobby
At noon, we crossed the border. It was always exciting being in Mexico, a country I learned to associate with great pleasure. During my dozens of trips there, I had acquired a penchant for the land and people, but not for Customs. There we were, packed to the pavement with tons of elaborate underwater equipment, trying our best to act nonchalant, like ordinary tourists out for a weekend's fun. The first official who looked in the van called another, who called another, who called another. In the meantime, Sheck was inside, efficiently going from desk to desk, getting our papers approved. By the time an inspector came inside to report the strange load, Sheck had all the documents signed and stamped. A minisummit was held in the foyer. We suddenly spoke no Spanish; just kept repeating "scuba holiday" whenever one of the inspectors glanced our way. Twenty dollars later we were heading out of Matamoros.
The highway's first 150 miles passed through sparse, flat agricultural land similar to southern Texas. Then, in the distance, we saw the mountains begin to rise. This was the emergence of the wild terrain that inspired B. Traven's classic, Treasure of the Sierra Madre, a bold frontier for hardy spirits where fortune and tragedy coexist only a heartbeat apart.
We spent the night in Victoria, choosing to wait for the freshness of morning before tackling the 100 miles of twisting mountain roads that wind their way to Ciudad Mante.
When we woke, the morning sun was still red on the mountains and the air cool. We set out early, so that we would be unhurried during the difficult drive. It was Easter Sunday. Mexico was dressed in its finest. All along the roadway well-groomed families followed the sounds of church bells to early services. The night's rest readied us for the mountain road, but as expected, progress was slow. It took three hours to reach Ciudad Mante. Sheck drove straight through the town without stopping. At the southern glorieta, we veered off onto a narrow road that led toward a distant mountain range. It was the end of the dry season, and Sheck was anxious to learn if the lack of rain tempered the spring's flow. The volume of water that surged up the crevice was a critical factor in how deep he would be able to dive.
As we approached, the dark mountain bluff began to show detail. Large runs of gray granite, separated by dense foliage, shot straight up from the plain. The closer we drove, the higher it grew, until the crest could no longer be seen through the windshield. We paralleled the cliff for a quarter mile before arriving at the spring.
While walking down to the water, we saw two dry-suited divers with fins in hand coming up the embankment. Sheck immediately recognized the men. It was Sergio and Angel, returning from their first dive into Mante. Warm greetings were passed. While the two cave divers removed their cumbersome gear, Sheck led me to where I could get a view of the spring cave.
There is was, exactly 1,464 miles from Sheck's front door, a cave entrance right out of a Spielberg movie. Looking down from the cliff, we watched the water pour from the mountain. It rushed from the bottom half of the cave entrance into a blue spring pool fifty yards wide. Although it was only midmorning, several bathers already sat cooling themselves on the basin's rocks.
We left the spring for town, following Sergio and Angel's jeep. After checking into a hotel, we ate lunch together. That morning they dived the cave to l80 feet. The visibility was fifty feet and the flow moderate. Conditions were good for Sheck's dive.
Sergio and Angel are expedition men in the purest sense--a pair that goes to exotic places to do extraordinary things. Himalayas, Peru, skydiving, rock climbing, and for the past five years, cave diving. They do such things for no other reason than the spirit moves them. During the difficult process of setting up and breaking down his dive, Sheck could have had no better help. Both men worked diligently, helping to stage the sixteen tanks in the cave, and were always available to do what needed to be done. One of their strengths is knowledge. Immediately they questioned Sheck about how he was going to put his dive together.
After lunch, Sheck made the decision to move the dive up a day. We had arrived at Mante ahead of schedule, weather was splendid, and he was anxious to get started. The change of plans meant that he had to make a 330-foot dive that evening to stage the deepest tank.
When we returned to the spring at 4:00 PM, the basin area was swarming with holiday bathers. During the two hours it took to prepare for the dive, Sheck was surrounded by onlookers who asked a ceaseless stream of simple questions. Hot, annoyed, and losing concentration, he finally asked the crowd to leave him to his job. Courteously, they all backed up a few paces and once again commenced with their inquisition. After he was finally outfitted and heading to the water, his faithful entourage followed closely at his heels. A few even splashed happily after him as he pulled his heavily equipped body through the current and disappeared inside the cave.
It was dark and the crowd long since gone when I saw his light beam cut through the pool. In the time he was down, I made a dive into the cave, explored the cliff above the basin, read several chapters in War and Peace, listened to samba tapes, and took a nap.
What a trial of boredom Sheck must have experienced during the same period while hanging from the rocks waiting for the nitrogen to seep from his tissue! That evening's decompression was only a quarter of what he would have to endure in two days. If a problem developed during the deep dive, forcing him up early, he was certain to sustain a serious bends hit. The shortest route for treatment to relieve his agony would be a ninety-mile drive to Tampico, a low altitude flight to the Harlingen, Texas, airport, and then an air ambulance to Methodist Hospital in San Antonio--the closest chamber.
The next day was long and busy. Fifteen additional tanks were tied off. Sergio and Angel secured stage bottles twenty feet apart from 160 feet to eighty feet, and at ten-foot intervals from seventy feet to thirty feet. Sheck made another deep dive, leaving two cylinders at 270 feet, one at 240 feet, and another at 210 feet. This time I followed behind, taking pictures. At 100 feet, I stopped in the center of the narrow passage and watched Sheck, silhouetted by his powerful light, go down beneath me until his beam evaporated in the darkness.
That night at eleven, when I turned out my reading light, Sheck was still knotting line and double-checking charts. In the morning, when I awoke, his bed was empty. I found him in the van, cleaning the second stages on his regulators. He was so intent in his effort that I said nothing and went back inside to dress. A moment later he came in. It was easy to tell by his actions that the paranoia was beginning to set in. To and fro, from box to bag he went with long quick steps.
"Good morning," I said.
He stopped and glanced around to where I was sitting on the bed.
"Can I help you with anything?" I asked.
"Good morning. Yeah, sure, here." He handed me a paring knife and a whetstone he had just taken from a gear bag. It was the knife from his wrist scabbard that would be used to cut the line at the dive's deepest point.
"Moving the dive up a day has set me behind," he stated. "Really shouldn't be diving today. It's already getting late, almost 7:00 now."
"Just wait until tomorrow," I suggested.
"Maybe; we'll see; I'm close now." He left the knife and stone in my hand and bounded across the room where he began to copy a duplicate set of decompression times on plastic tags.
"Hey, another day doesn't matter. Why not wait?" I asked.
He glanced in my direction. "To tell the truth, I don't want to think about it another day. We should be out of here in half an hour."
We arrived at the spring just before eight. Not three sentences were passed between us on the ride out. His thoughts were lost in the dive. Not one of the dozens of important details could be forgotten or his attempt would end in failure. Like a team whose pitcher is going into the ninth inning with a no-hitter, Sergio, Angel, and I ignored Sheck. We sat twenty yards away, on the tailgate of their jeep, watching him ready his final equipment.
Sitting there, my thoughts went back to a conversation I had with friends from Miami just before I left for Mexico. We were discussing Sheck's proposed dive. One of the questions they asked was, "How are you going to feel when Sheck actually starts down?"
Then I was rather flippant with my answer, but now, close to the dive time and more educated about the difficulties involved, I began to rethink my position. Those who knew about decompression with mixed gases, both in the navy and commercial diving business, gave Sheck no better than a 50/50 chance of surviving the attempt. Decompression was only one problem he had to overcome; there was also helium's high pressure nervous system syndrome, hypothermia, oxygen poisoning, pulmonary edema, equipment failure, and because he was using nitrogen in the deep mixture, narcosis. Sheck was learning how to put the entire package together and now was the time to see if it worked.
He is not a daredevil; he is an explorer who spent twenty years preparing himself mentally and physically for underwater challenges. In the years I have known him, I have acquired an almost mystical confidence in his ability to accomplish amazing dives. He is simply the best and most experienced diver in the world. If it were physically possible to pull off a 700-foot-plus dive, Sheck was the one who could do it. As I watched him make his final preparations, the question for me was not whether he would survive the dive, but how deep would he go?
At 10:45 AM when he finally entered the water, perspiration was beginning to soak the heavy wool overalls he wore inside the sealed dry suit. His face was scarlet. On his back were two 100-cubic-foot cylinders containing trimix. Slung under his chest and extending below his waist were two additional tanks--one filled with air to begin the dive, in the other, trimix.
With a nod he submerged.
From a narrow ledge above the cave, I watched as he pulled himself toward the entrance. Once he was inside, I walked a distance down the Rio Mante and sat alone in the shade of a palm thicket. I leaned back and began to imagine Sheck's present situation.
Eight minutes pass after he enters the cave. He is 100 feet inside the dry chamber, kneeling on a shallow rock shelf, meditating. The brief rest allows his pulse to settle and his mind to clear the predive pressure. Periodically he plunges his maskless face into the cool water.
Two minutes later he turns on his four backup lights and the bright primary unit built specially for the 700-foot dive by English Engineering. With the regulator to the air tank gripped between his teeth, he pushes his weight off the ledge, gains control of his awkwardly ballasted body and swims fifty feet underwater to the lip of the drop-off. He checks the exact time and enters the figures on his slate, purges the last bit of air from his buoyancy vest, and begins to descend into the crevice.
Against the strong flow, he pulls himself down arm over arm, following the line on the south wall. Three minutes into the dive, at 190 feet, he skirts left over a rock promontory, and then once again down. Here the passage widens to fifteen feet, and the walls are much smoother; he is forced to kick to keep his pace. His pulse quickens slightly with the added exertion, and he slows his effort as he passes the stage bottles at 210 feet, and then 240 feet.
Six minutes into the dive, 270 feet below the surface, he makes his first brief stop to exchange his air tank for the waiting cylinder of trimix. At the ten-minute mark he knows he is 400 feet down when he spots the blue garter left by Mary Ellen last June. The crevice walls are now separated by thirty feet of water--their widest point. His descent is in control.
At 520 feet he briefly pauses to attach his backup watch and two depth gauges to the line and begins to breathe the trimix on his back. The attached pressure gauge and his watch are now the only instruments to monitor his situation. Their readings are vital.
Six hundred sixty feet below the mountain he arrives at the line's end. It is seventeen minutes since he started his descent. He attaches the line from his reel and begins his drop into depths never before reached by free-swimming man. "As I entered the unexplored cave zone, I was concerned about my slower-than-expected rate of descent. I forced myself not to pick up the pace. Instead of continuing its vertical drop, the crevice began to narrow and run at a sixty-degree angle. Flashes of narcosis were becoming more prominent. I glanced at my pressure gauge. I had a problem; the reading hadn't changed since my last check. I banged the unit on my tank. The needle jumped several hundred pounds lower. Pressure had forced the lens against the needle, but had it stuck again? I had no way of knowing. A projection to tie off was just below. I passed it and dropped deeper. The tunnel began to flatten out, falling at a forty-five-degree angle. I looked at the pressure gauge; it showed a third of the gas was gone. Was the reading correct? I had been down just over twenty-two minutes. It was time to get out.
"My light beam fell on an excellent tie-off twenty or thirty feet down. I took a breath and moved toward the projection, when suddenly a jolting concussion almost knocked me unconscious. I looked behind for a ruptured valve or hose. There was no leak. Something had imploded from the pressure, but what? I drew another breath and kicked the last eight feet to the tie-off. Quickly, I threw two half hitches around the rock, reeled in the loose line, and made the cut. My down time was twenty-four minutes ten seconds.
"I wanted to move fast from the deep water, 120 feet per minute if possible. The current that I had battled during my descent helped to lift me up the incline. I drew a breath and felt a slight hesitation from my regulator. The next breath came harder. Was I out of air? Again, I hit the gauge on my tank but this time the reading didn't change. If I was forced to use the gas in my belly tank, I would miss all my decompression to 330 feet where my first stage bottle was tied off. I switched over to my backup regulator and with relief drew a full breath.
"At 520 feet, I untied the gauges and started my decompression. It was strange to be decompressing at such a depth, knowing that only one person had ever gone deeper. I remained for a minute and then began to ascend at the rate of ten feet per minute until I reached 340 feet. When I saw my first stage bottle and knew that I had spare gas around me, I finally began to relax. My stress was gone, but the long decompression stops were only beginning.
"Now, with extra time, I began to search for the cause of the implosion. The source was the large Plexiglas battery housing for my primary light. The pressure had been so great that the three-quarter-inch lid was forced into the casing, crushing the pack. Amazingly, the light still functioned. Next I counted the knots on the line remaining in the reel. I factored in the angle of the cave's lower reaches and estimated that I dived 780 feet, a world's record depth for a surface-to-surface dive."
Three and a half hours after we last saw Sheck, Sergio and Angel made a dive to locate his position and offer assistance if needed. They found him at 100 feet, suspended behind a cluster of twelve empty scuba tanks. Sergio handed him a slate with questions prewritten in English. Sheck wrote the answers in Spanish. At 9:30 PM he finally arrived back at the surface. Sergio, Angel, and I were waiting in the light of a butane lamp. He had been below water for ten hours and forty-three minutes, but his decompression dues were still unpaid. For thirty additional minutes, he remained kneeling in the basin breathing pure oxygen.
When he emerged from the water, he resembled an old man. His face and hands were severely wrinkled and his walk faulty. Three times, on his way to the van, he stopped to calm his racing pulse. Later, while struggling to free himself from the dry suit, I saw weariness set deep in Sheck's face like I had never seen in another man. What came to mind was Hemingway's description in The Old Man and the Sea of Santiago's utter exhaustion after his battle with the sharks.
We were up early the next morning. Sheck was surprisingly strong. He did most of the work repacking the van and drove 300 miles of Mexican highway before the day was over. At the beginning of our return trip, just after leaving Ciudad Mante, I asked him a question that had haunted me since the dive. "Will you ever do it again?"
From behind the wheel he cocked his head, gave a sly half smile and answered. "I don't know."
On April 6, 1994, Sheck Exley failed to return from a cave dive at Zacaton Cavern in northeastern Mexico. The greatest happiness is to fulfill one's uniquenss. Such fulfillment Sheck Exley achieved. Read More...