Tragic Tales of Ressel Cave: Adventures, Challenges, and Loss

Incident LocationDiver Names
France, Ressel CaveRobert Kozabek, Unnamed Belgian diver

Located in southwestern France, Ressel cave holds lots of memories for divers, some pleasant and some unpleasant. We’ll explore how a group of divers planned to push the limits of the cave on August 3rd, 2013. This exploration proved more challenging than they had anticipated when their equipment started to fail and their lives were at risk. Would they make it or not? Would other consecutive dives be successful?

Several caverns in France’s Loth and Dordonia regions are appropriate for divers of all skill levels and are located in lovely agricultural settings. The Dordonia, the Lote, and the Salee are the three rivers where sites are most commonly found. The Midi-Pyrenees region, which spans from the boundaries of the Dordonia Valley to the highest peaks of the Pyrenees and forms the heart of southwestern France, includes the Lote area in its northernmost portion. Every year, cave divers from all over the world come back to dive here. France is one of the best places in the world for cave diving, with over twenty thousand caves known to exist because most European divers take their cave training there instead of in Mexico or Florida. The region in France is well-known, and Ressel is one of the most well-known caves in the area.

This underwater cave, located in the center of French cave diving country, is known for being one of the more intriguing, tough, and technical cave dives. The facilities are pleasant; there’s a spacious parking area for vehicles, and ultimately, there is also a conveniently positioned structure with a bathroom. Divers just need to walk around 330 feet from the parking lot to the river sale entry point where they may set up all their dive equipment. The entrance is quite large at 492 feet before splitting into two arms that rejoin at a distance of 984 feet. A series of drops continue until they reach a depth of 252 feet before ending and ascending once more to reach a dry area of the cave around two kilometers from the entrance.

Ressel Cave Exploration

In 1968, spelio club divers Martine and Deborah dived to 492 feet. The line was only expanded to 984 feet with a maximum depth of 100 feet in 1973, reached pit 4, and descended 147 feet in 1975. During the years, more exploration was done, particularly by Yokum Hassameyer in the early 1980s when he buried his knife in a rock and attached his line to it at a depth of 3,609 feet into the system. That knife is still there. Ressel cave has been the subject of numerous expeditions in the past. One of those was performed with a rebreather and an open circuit. As time went on, cave divers became more accustomed to the cave, which facilitated further investigation. The first dive to the other side of the first sump took six hours. It was discovered that with practice, the timing could be shortened to three hours for the same dive. On successive dives, this is because during cave diving, it’s crucial to move cautiously yet steadily. After all, doing so will shorten the decompression period, memorize the location, reduce time lost, and increase the efficiency and fluidity of the dive.

Terrain in Roselle cave in Lote France. This undoubtedly took years of preparation. The mission was an exploratory dive that would last for a couple of hours. Let’s know more about the crew that made it possible. Without the assistance of a team, an exploratory dive into a cave of this difficulty was not feasible.

There were extensive preparations, including material testing, by a few members of the Diving Club Technical Diving Antwerp and the Flemish Cave Exploration Group Science Explorers. Eric Wilders, Ronnie Brayer, Sani Versus Kenny, and Angie Von Dorne and Friedrich Funderplus were on the dive expedition team. The tasking work of setting up the tanks and the bailouts was completed by the support divers Rani Sani, Kenny, and Angie.

The crew also included Edvick Dirard, the caving club’s photographer. Despite having undergone recent knee surgery, Rick Vondananda, the founder of Technical Diving Antwerp, offered his years of experience in this exploration. One can say that this is a perfect team for a challenging dive. There is a need for adequate preparation before participating in a demanding dive like this.

The objective was to enter the cave and explore as far as possible. They wanted to reach some five during this exploration dive. Inspiration rebreathers were utilized to limit the number of breathing gases. For the logistics, the 1060 diluent in three-liter bottles and pure oxygen were the gas mixtures for the two push divers. Support divers Ronnie and Sani placed an open circuit bailout for some one. More tanks were positioned at 3,609 feet. The equipment left in sump 1 at 3,609 feet would be collected for the real push through to complete the crossing of sump 1 and all subsequent sumps.

The actual crossing began with one CCR for each diver, along with a scooter and a 20-liter tank filled with 15/45. Other materials that were abandoned after 3,609 feet would be collected. There were four scooters utilized: three Bonex and one Silent Submerge. Many cave divers are familiar with the beginning of sump 1. Many of them had their training there. It has a pretty simple entrance that is broad and well lit. Most people dive into this initial system up to a depth of 1,312 feet, where a well-known deep drop is situated. The expedition’s main goal was to push through this sump and make it to the other side.

The longest dive was approximately two kilometers long and reached a maximum depth of 246 feet. The majority of that distance was between 164 feet and 255 feet below the surface. Reaching the next sumps and perhaps the cave’s exit was the expedition’s secondary goal. After 47 minutes, the team got to the vertical wall where sump 1’s ascent begins. Eric was aware of how quickly things would go from prior experience. This was where the deco in sump 1 began. Sump 1 took 122 minutes from start to finish. A total of 120 minutes was spent underwater in sump 1 within NDL limits. Divers explored the other sumps. It would take 12 hours to travel across to sump five and back. Five and a half hours, in total, would be spent underwater, and the remaining time used to transport equipment between the sumps. There were two rest periods of 15 minutes each.

Although the dive itself wouldn’t be too challenging, moving the equipment between the sumps made this dive quite difficult. The level of CO2 is very high between the sumps. Sadly, despite all their planning, something went wrong. One of the Bonex scooters was mistakenly dropped just past sump four and flooded. As a result, it continued to function until the weight became intolerable. On the way back into sump three, another scooter was exhausted. Opening the tank caused one high-pressure hose to split apart. It was a brand new Myflex high-pressure hose. Therefore, diving the Ressel cave up to sump five proved to be a significant difficulty for the Belgian cave divers. It was not just incredibly complicated but also very motivating because of the years of training, getting physically fit, performing deco calculations, filling the tanks, making preparations, and thinking out logistics. Also associated with this dive was a significant psychological challenge that was both physically and mentally taxing. Therefore, to these divers, the cave’s end remained undiscovered. That was not, however, the end of exploration at Ressel Cave.

In recent years, there have been numerous explorations, such as the emergence to Ressel Survey into Credit Hall during a dive exploration from the team of Gunther Fall and Pedro Belardi in 2020. The purpose of this project was to search for continuations in the last sump from the T-junction where the passage splits into the North and South tunnel. Besides, they wanted to search for the fall at the end of the Ressel cave system for a possible passage through the boulder choke. Unfortunately, they found out that there is no way to move through that passage, so the North tunnel was closed. However, they were able to create a survey of the whole polygon until Credit Hall on just one dive using the ENC2 device, an underwater electronic navigation console. They managed to create a great navigational aid for divers to help them navigate in cold murky waters.

The first incident

Over the years, some incidents have happened in this cave system. The first occurrence involved Polish cave diver Robert Kozabek, who arrived in France at the beginning of May 2021. “We are starting the full cave diver course,” he captioned a shot that he sent to his Facebook site. He had a solo dive planned for May 8, 2021, which was also his 53rd birthday. At the time, Robert had been diving since 1987 and was the scuba diving teacher. So, he was an experienced diver. Since 2007, Robert was the owner of the Bork company. He assisted disabled people and worked with teaching disabled divers in the Handicapped Scuba Association system. He was also an associate member of the Nautica Underwater Tourism Center Association. He authored research papers on diving for impaired individuals and diving methodology for people with disabilities.

The diving exploration of one of Europe’s most challenging caverns was a fantastic adventure and a huge challenge for Robert, who had previously done a lot of caving. He proceeded in his determination to educate and develop as a diver. He taught swimming and first aid classes in addition to diving, and he held a master’s in physical education. He had been a lifeguard, a non-commissioned officer in the Polish Army, a paratrooper, and a member of the 56th Combat Helicopter Regiment. Before his birthday dive, he participated in a TDI cave instructor training course in France with a few other Polish instructors. However, very few cave divers will enroll in the TDI cave instructor training because of the requirements. For instance, cave divers who wish to enroll in this course must have completed over 200 cave dives, hold a TDI introductory cave instructor certification, and have held an Open Water teacher certification for at least two years. This demonstrates Robert’s expertise as a cave diver.

Robert also posted some technical details about his intended dive equipment on Facebook. On the day of the incident, he planned to spend about three hours on this dive and cover a total distance of 8,202 feet. Robert encountered a challenging circumstance on Saturday at 4:30 PM as he was beginning to dive. Around him were other practitioners when the experience first began. He was not yet 32 feet below the surface. He had to be pulled out of the water by other divers, including Swiss, French, and German divers. He was quickly pulled out of the water and given a cardiac massage before being cared for by paramedics who raced to the area. An experienced instructor was in charge of the field trip when the catastrophe happened. She was the one who massaged Robert’s heart while he waited for assistance. He was brought to a Kahor hospital while still unconscious and in serious condition. Robert tragically died in the hospital three days after the event. It is unknown if a heart problem or a technical malfunction led to the accident. Authorities in France looked into the disaster’s causes. Robert might have passed away as a result of the closed ADV-induced hypoxia, according to one of the opinions. Robert was unable to safely complete the intended dive because, according to his previous CCR instructor, he lacked the knowledge, expertise, and experience necessary. He hadn’t finished the cave instructor course they had previously discussed. Robert was certified to undertake single-stage CCR diving in open water with air diluent minimum oxygen of 21 or above without a DPV (Diver’s Propulsion Vehicle). At the time of the incident, it was evident that Robert didn’t adhere to all the standards and scope of his training. He should have gotten at least CCR Trimix, CCR Cave, and DPV Cave certifications for the dive he had planned.

The second incident

The second incident happened on October 7, 2021, on a Thursday at 12:30 PM. A 39-year-old Belgian cave diver went for a dive into the Ressel cave. He was with three other Cave Exploration Club members from Belgium. This crew was going to enter the Ressel cave for the first time. The Belgian diver entered the cave to explore it, but he became stuck after descending 32 feet and approximately 65 feet from the entrance to the resurgence. The Belgian diver may not have been able to fit through the passage, so they paid particular attention to it during their preparation study and briefing. The diver tried to fit through the cave’s restriction, became caught, and his rebreather’s counter lungs compressed and emptied. As a result, his hands and arms were extended in front of him in a posture that prevented him from reaching the rebreather’s control valves or his bailout. His teammates came to rescue him and called the emergency services after he failed to return to the surface. Unfortunately, his teammates were not able to remove him from where he was stuck, and he finally died of cardiac arrest at that depth. The deceased was trapped there, and there would have been enough breathable gas for about five hours if the counter lungs had not compressed and the controls had been reachable. This may have been more than enough time for a rescue to be made instead of a recovery. The deceased diver was removed by the fire department’s Rescue Squad in around 45 minutes, and their assistance ended just after five o’clock.


What is the location of Ressel Cave?

Ressel Cave is located in southwestern France.

Who were the divers involved in the cave exploration?

The divers involved in the cave exploration were Robert Kozabek and an unnamed Belgian diver.

How long is the cave and what is its maximum depth?

The cave is approximately two kilometers long, and its maximum depth is 246 feet.

What were the incidents that occurred in Ressel Cave?

The first incident involved Polish cave diver Robert Kozabek, who tragically died after encountering difficulties during a dive. The second incident involved a Belgian cave diver who became stuck and later died while exploring the cave.

What were the causes of the incidents?

The exact causes of the incidents are not fully known, but potential factors include technical malfunctions, lack of experience or training, and challenges within the cave environment. Investigations were conducted to determine the specific causes in each case.

Patrick Broin
Patrik, a seasoned cave diver, shares his first-hand experiences and expert insights on the treacherous world of cave diving accidents.
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