Canadian cave divers and rescuers say there's no way 12 trapped boys and their soccer coach could make their way out of a flooded passage in Thailand without experts guiding the way.
Chris Foisey, a St. Catharines -based scuba instructor with experience cave diving, says the rescuers are doing most of the heavy lifting in the operation.
The dangerous underwater rescues considered a last resort involve two divers accompanying each of the boys, none of whom had experience diving before they were found on July 2.
The boys and their coach went exploring in the massive Tham Luang Nang Non cave on June 23 after a soccer practice, and were cut off when a rainstorm flooded the cave.
Foisey says diving in caves is complex and disorienting, with no light to guide the way.
He says it's important to have experienced divers who know how to figure out which way leads out of the cave and which leads them farther in.
The rescuers will be looking for signs including the direction the bubbles are travelling in order to figure out where to go.