‘What have I done?’ thought Joanne Appelbee as she waited for rescue with her two other children in rough seas off Western Australia

The teenager is praised for his courage and bravery after swimming back to shore to raise the alarm.

Teen swims 4km, two without a life jacket, to sound alarm which led to the discovery of his family

Austin Applebee recounts his 'superhuman' swim which saved the lives of his mother and siblings in Australia.

‘What have I done?’ thought Joanne Appelbee as she waited for rescue with her two other children in rough seas off Western Australia

Doctors told 13-year-old his swim put strain on his body comparable to running two marathons

Saltwater, survival backstroke and sheer mind over matter may have helped the teenager save his family, experts say