The challenges and risks facing the international team attempting to rescue the Thai footballers cannot be overstated. Trying to rescue a group of children trapped under rising floodwater, in more than 10 kilometres of winding caves, will test rescue divers and their technology to the limit. The divers are working at extreme depths, moving slowly through unfamiliar and pitch-dark flooded caves. All they will be able to see is what is illuminated by torchlight. It is also unlikely the water is clear – sediment and pollution can severely reduce visibility, meaning they may have to feel their way through the gloom. The depths and distances they are trying to travel means the rescuers are using rebreathers – closed-circuit equipment that recirculates and “scrubs” the CO2 out of expelled air to increase the amount of time a diver can spend under water. <strong>____________</strong> <strong>Read more</strong> <strong><a href="https://www.thenational.ae/world/thai-cave-rescue-mission-to-save-the-boys-begins-live-updates-1.748005">The mission to save the boys begins - live updates</a></strong> <strong><a href="https://www.thenational.ae/world/asia/new-video-shows-boys-in-thai-cave-in-good-health-1.746903">New video shows boys in Thai cave in 'good health'</a></strong> <strong><a href="https://www.thenational.ae/world/asia/thai-boys-trapped-in-underground-cave-are-found-in-pictures-1.746546">Thai boys trapped in underground cave are found - in pictures</a></strong> <strong>_____________</strong> Rebreathers are traditionally back-mounted, bulky and sometimes fragile. Online posts suggest British rescuer Richard Stanton, one of the experts in Thailand, has a front-mounted unit to allow for greater “wiggle room” through narrow cave openings. But locating the young footballers was only the first part of the problem. How to get the group out of the caves is another. Firstly, the boys cannot swim. Rescuers are considering training the boys and their coach to scuba dive. Even if this happened, even if the boys are not afraid of the water, and even if they could be put into equipment they can use to breathe, each child may not be able to carry enough air to make the full length of the journey. One solution would be to position air-filled “stage tanks” along the route. As one cylinder was depleted, it would be swapped for a full one, again and again, step by step, as they exit through the cave. But some of the cave openings are so narrow, the rescuers have to remove their equipment, push it through the gap ahead, climb through and then gear up again. If all of this was possible, a rescue with one untrained diver could be fatal for both. At best, repeating this with 12 Thai boys and their 25-year-old coach is going to be slow-going and dangerous. <em>Nic Ridley is production editor of The National and a PADI Master Scuba Diver Trainer</em>