This is what I was told as a teenager 30 years ago on vacation in SW of France (Moliets-Plage). They told us to tread and wait either for the flow to bring us b

This is what I was told as a teenager 30 years ago on vacation in SW of France (Moliets-Plage). They told us to tread and wait either for the flow to bring us back, or for them to get to us (in a helicopter, usually)