The Thai Cave Rescue, Before Its Triumph, Teetered on the Brink of Disaster

Thai Navy SEALs were quickly trying to learn the basics of cave-diving—their training is in open water and they had no cave experience, a much more complicated and dangerous endeavor.

When it came time to decide who to take out first, the boys decided on their own, presenting Thai SEALs with a list of their names in order, Thai authorities said.

.. Then, on Tuesday, shortly after the group inside the deepest cavern had been pulled to safety, a piece of equipment that drained water to levels that made the escape manageable broke. Without the pump, torrential rains that night sent water levels soaring through the cave.

“It’s lucky we completed our mission yesterday, because the cave is covered by water again today,” Royal Thai Navy SEAL commander Rear Admiral Arpakorn Yookongkaew said on Wednesday.

.. The rescuers were aided by a combination of luck and an outpouring of support from a motley group including military experts, international cave-divers, medical personnel and a Thai rock singer and her fan club.

.. The effort enlisted more than

  • 900 police officers,
  • 10 police helicopters,
  • seven police ambulances, more than
  • 700 air canisters and
  • thousands of rescue workers.

Volunteer cooks dished out more than 5,000 meals a day for the people on the ground. When divers needed wetsuits, air tanks and regulators, volunteers collected hundreds more than needed.

.. Another group of Thailand-based cave divers was pulled together by Narinthorn Na Bangchang, a Bangkok-based actress and singer

.. Ms. Narinthorn flew to Mae Sai the night of June 25 with Ruengrit Changkwanyuen, an IT specialist and diving enthusiast who became a go-to person for the SEALs for information on cave-diving gear and techniques

..  While divers in open water can return to the surface if they get into trouble, cave divers have to contend with dark, disorienting caverns, strong currents and low visibility in muddy water. In emergencies, cave divers can’t easily return to the surface and need to carefully monitor their air supplies.

.. In an attempt to lower water levels, engineers set up heavy-duty pumps to drain water. In the 2½ weeks the boys were trapped, they pumped a billion liters of water out into the surrounding farmland and river system, enough to fill an Olympic-size swimming pool 400 times over.

.. The pumping effort allowed rescuers to lower the water level in key areas, providing dry ground for staging areas and places where divers could refresh their supply of air. Volunteers laid cables, lighting and guide ropes.

.. Volunteer divers worked alongside the Thai SEALs to try to locate the boys’ cave. They formed teams that pushed forward 200 meters at a time, supplied by other divers and volunteers who formed a “daisy chain” to pass tanks inside and place them at 25 meter intervals so the divers would have a constant supply of air.

.. Royal Thai Navy personnel carry a portrait of Saman Gunan, a former Navy SEAL who died during the rescue operation.

.. Pumping out water had been successful—three kilometers beyond the entrance of the cave had been all but dried out completely—but forecasters warned of heavy rains in the coming days.
.. Conditions in the cave piled on further pressure. Oxygen levels were down to 15% in the boys’ chamber, well below the normal 21% in the atmosphere. A level of 12% is considered seriously hazardous to health.
.. Thai SEALs and volunteer dive experts had created a plan that posted two seasoned cave divers, most of them foreigners, at nine stations along the way to the entrance.Each boy was placed on a stretcher, wearing a wetsuit and full face mask, with an air tank at his side. Each pair of divers carried the stretcher along the cave passages, and through submerged tunnels and open chambers, meaning that the boys didn’t swim or climb at all, said a person familiar with the operation.

.. The boys were medicated to keep them from panicking underwater, but weren’t rendered unconscious