New world record for cave diving exploration.
On November 3, 2023, during a 7-hour dive in the Font d’Estramar resurgence of the Pyrénées Orientales, in France, Marseille cave explorer Frédéric Swierczynski reached the astonishing depth of 308m (1010.5 feet).
Frederic Swierczynski, 50, is a well-known trimix, cave, and rebreather instructor from Marseille France who has been diving since the age of 12. He made his first solo trimix dive to 120m (393 feet) at the age of 18 and began using rebreathers in 2000.
Nuno Gomez of South Africa held the previous official record of 283m (928ft) until Frederick surpassed it on November 3, 2023. Nuno dove Boesmansgat, also known as “Bushman’s Hole”, is a deep submerged freshwater cave (or sinkhole) in South Africa’s Northern Cape province. Nuno had to follow a decompression schedule for an equivalent sea level dive depth of 339 m (1,112 ft) to avoid decompression sickness because the cave is located at an altitude of more than 1,500 m (5,000 ft) above sea level. His total dive time was 12 hours and 15 minutes, with a 14-minute descent and four minutes at the bottom.
Swierczynski carried six tanks in total: two 2-litre tanks of pure oxygen and diluent in each CCR, plus a 2-litre tank of compressed air at 374 bar for suit inflation and another of 4/89 diluent off-board. The CCRs had upgraded 3kg Sofnolime filters due to the depth to reduce the risk of CO2 poisoning.
Font Estramar springs from the foot of a small cliff on the edge of a 200m-high limestone plateau and drains into the karst hydrosystem of the Corbières in the south-east of France. The temperature of its brackish water is constant at 17.8°C.
The pond, spring, and cave system are well known, with numerous fatalities recorded in the caves. One diver who died was an emeritus diver on Luc Long’s underwater archaeology team back in July 2023. Divers, including Jacques Cousteau, had been exploring the system since 1949. The main breakthroughs over the last decade have been made by fellow-French diver Xavier Méniscus, who had reached a depth of 286m, 1,020m from the entrance, by 2019.
Divers with limited experience going to significantly deeper depths than they are trained for can be a recipe for disaster. The volume of air a diver consumes in a given time typically increases with depth due to pressure effects—go deeper, breathe more. Other factors that can increase a diver’s air consumption rate include exertion while swimming, speaking, and cold water, to name a few. Stress is another significant contributor to air consumption. Even an experienced diver with a high air consumption rate would quickly deplete their scuba cylinder at 47m, (154f) Swierczynski spent months preparing for his attempt by running in various environments and diving to depths of more than 260m (853f).