Top guns of American cave diving

by Mike Wisenbaker

Just south of Tallahassee, Florida, hundreds of depressions and karst windows (surface openings into caves) breach a huge limestone region that geologists call the Woodville Karst Plain. It stretches over 1,166 square kilometres, from Tallahassee’s south side into the Gulf of Mexico, and holds seven of the state’s 27 first magnitude springs (those with a minimum average flow of 245 million litres per day). One of these, Wakulla, has been a magnet for underwater cave exploration since the 1950s, when students from nearby Florida State University first penetrated the mammoth vent of the spring. Wakulla now represents the Everest for the world’s best technical divers.

Naturalists have speculated on Wakulla’s origins ever since the 1830s. Serious cave exploration in the region, however, moved at a glacial pace until about 1986. At that time, a man named Parker Turner came on the scene and established what later became known as the Woodville Karst Plain Project (WKPP). He informed his fellow underwater explorers that the area south of Florida’s capital city had an enormous potential for unknown and uncharted caves. His intention was to put together a group of explorers to probe these extensive labyrinths, known as Tallahassee Power Caves, and to provide researchers and agencies with information from these dives.

Original members such as Bill Gavin (a US Navy rebreather engineer) and others were the first to attempt deep cave diving here using a systematic and consistent approach. In 1990, the Woodville Karst Plain Project became an official project of the National Speleological Society. The WKPP now has 100 or so dedicated volunteers, including world class cave divers, engineers, naturalists, scientists, students and others. In terms of exploration, the team has been described as the best-kept secret in cave diving. While they do not strive to set records or to gain notoriety, they are setting the pace for cave diving exploration throughout the world. Scott Brunsdon, a New South Wales cave diver, explains how the WKPP has affected him: ‘I was looking for an alternative to my gear configuration because I was unhappy with it. Most cave divers in Australia are helmet-wearing butt mounters (referring to the battery canisters for their primary lights). When I asked why they wore their gear the way they did, they told me that’s how they always have done it, and that’s how they were taught.

‘The amount of gear that people are wearing is astounding – six lights, helmets, spare masks, tech BCs, twin independents. When I saw the Hogarthian system, I was amazed. I had always wondered how the WKPP accomplished the dives they did while wearing so little gear. Then I thought about it, and now I don’t know how I managed to survive diving the way I used to. The WKPP has always helped anyone who asked questions about what they do, and I like that. This is a dangerous sport, and the way the WKPP spread the knowledge gained by years of experience and accomplishments can only be a credit to the sport and will maybe save some lives in the process. For this reason, I am trying to spread the word about the Hogarthian system as much as I can in Australia and the southern hemisphere.’

WKPP explorers routinely stage trimix and other gases, as well as super scooters, at multiple locations. They inflate their drysuits with argon to prevent hypothermia during deco stops, which sometimes run for more than 12 hours in the 20.5ºC waters. The divers employ ‘doing it right’ configurations that call for highly streamlined, and only essential, gear that allows them to move through the water with the ease of dolphins. Project director George Irvine sums up the philosophy of the group: ‘If you are looking for cave diving of a serious nature with a purpose in mind, do what I did. Ask who is the best in the business, and hang out with them. In other words, check with the WKPP.’ While this may sound opinionated, Irvine backs up his words time after time through his deeds. Since he took over the program about five years ago, no deaths or serious accidents have occurred, even though the team has made more than 2,000 dives. Team members must keep themselves in top mental and physical condition, eschewing the use of tobacco and other drugs. Irvine insists on the use of only the best-suited equipment. If such gear is not available, the team makes its own, such as the super scooters designed by Gavin and built by Irvine for use at depths of 90 to 120 metres, with burn times that exceed two hours.

Not only has the WKPP benefited the global diving community with its innovations (it has even spawned a new diving equipment manufacturer, Halcyon) and techniques, new deco tables are being developed based on the thousands of dives made by WKPP divers. This should result in safer scuba diving for everyone, especially technical divers doing multilevel dives with mixed gases such as nitrox and trimix.

While using gear designed with extreme cave diving in mind and putting together a dedicated group of people working toward achieving common goals, the team reaches ever farther and deeper into the bowels of the north Florida underground. Underwater cavities in the karst plain range in size from a gallery called the Black Abyss, large enough to hold a small skyscraper, to tiny fissures that only eels can pass through. The WKPP, and a few individual explorers before them, have linked 27 karst windows like beads on a string through more than 27 kilometres of twisting passages in the Leon Sinks Cave System. This places the system well within the top 80 longest caves, wet or dry, in the world. The maze currently ranks as the most extensive submerged cave in North America north of Mexico, and the third longest underwater cave in the world. Furthermore, the end of the line in Leon Sinks rests tantalizingly close to Wakulla Springs. As of July 1997, WKPP divers had mapped more than seven kilometres of passages in Wakulla at depths averaging just under 90 metres. The ultimate goal of the team is to explore and join Leon Sinks Cave, Indian Springs, Shepherd Spring, Chip’s Hole, Wakulla Springs and adjacent cave systems.

Many people wonder why WKPP divers willingly face the perils of tracing these deep, dark conduits. Whatever their reasons, these individuals provide critical data on the origins and paths of the region’s drinking water. Water clarity at Wakulla Springs seems to have diminished greatly as growth around Tallahassee has spread like a tumour into the surrounding landscape. Visibility in the spring in the 1950s usually ranged from 90 to 60 metres; now the team is lucky if the system is clear for an entire season. The glass bottom boats that ferry tourists over the spring vent at Wakulla run for only a fraction of the time that they ran in the past. Several years ago, turbid surface waters from heavy rains entered the sinks upstream and kept the spring black for almost two and a half years.

With this in mind, the WKPP team provided data to scientists and government officials that helped prevent a misguided developer from putting an underground petrol tank in an area underlain with porous limestone, just a short distance north of Wakulla. It is known that only one litre of gasoline can pollute 10,000 litres of groundwater. A leak into the Florida aquifer would be catastrophic to the region’s economy, not to mention wreaking havoc on its delicate ecosystems. Perhaps WKPP divers can soon pinpoint the main source of turbid waters entering these massive conduits. If the team is successful in its efforts, Wakulla Springs’ crystalline blue waters that have been attracting visitors for more than 10,000 years may be restored.

A brief description of some of the WKPP’s achievements speaks for itself: 1988: Bill Gavin, Lamar English, Bill Main and Parker Turner completed a 2,652 metre traverse from Sullivan Sink to Cheryl Sink. This traverse remains a North American record. Many setup dives and countless hours of planning and preparation were needed to accomplish this goal, as well as those that were to follow. Spring, 1996: George Irvine, Jarrod Jablonski and Casey McKinlay entered Big Dismal Sink and connected this system with the Leon Sinks Cave System when they reached the line in the Bitter End Tunnel leading to Cheryl Sink. This means the maze now ranks as the most extensive submerged cave in North America north of Mexico. It may very well turn out to be the world’s longest underwater cave, but with average depths anywhere from five to ten times deeper than the warm, shallow systems in Mexico’s Yucatan peninsula, efforts must be gradual. The depth factor alone makes dive planning infinitely more complex than what is needed to explore underwater caves in Mexico. Summer, 1996: George Irvine, Jarrod Jablonski and Brent Scarabin traveled 3,049 metres from the cave entrance into the inner reaches of Wakulla Springs. This established a penetration record at depth (87 metres) using open circuit scuba. Autumn, 1996: Rick Sankey and Brent Scarabin set a new world penetration record of 4,300 metres for any depth in the Chip’s Hole system in northern Wakulla County, Florida. They added several hundred metres of line to the legendary Sheck Exley’s great effort of 1989. For all practical purposes, they were more than 4,573 metres from the nearest surface air source.

When the divers do the swim through from Big Dismal Sink to Cheryl Sink, they will make a traverse of 3,872 metres, thus reclaiming another world record and besting their North American record. The only thing keeping them from doing this now is having to wait for the water in the system to clear. The team never compromises the safety of its divers.

In short, WKPP divers have the end of the line in just about every major cave in Florida. The team sets the standard for the most demanding cave diving exploration in the world. Although focusing on caves in Florida’s Big Bend, WKPP members have also explored 18 systems in Mexico and 25 in the Bahamas, and recently surveyed caves in Turkey and Brazil. The team was the first group of cave divers to use trimix regularly and to make use of experimental decompression tables generated by Hamilton Research. Last year the WKPP entered a new phase of cave diving as George Irvine, Jarrod Jablonski and Brent Scarabin set a new penetration record of 3,334 metres using Halcyon (semi-closed circuit) rebreathers at an average depth of 87 metres. As divers get more familiar with this equipment, the exploration potential of the team will become unfathomably greater.

For more information on the Woodville Karst Plain Project, see their web site at

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