October 2010 (ROTM #22) The Great Rip Current Experiment at Bondi Beach, NSW Australia

The big 'swim parallel' or 'stay afloat' debate about what to do when stuck in a rip is still going. So Surf Life Saving Australia graciously provided myself and some colleagues at the University of New South Wales some funding to run an experiment at Bondi over a few days in September. We worked in the rip in the background of this photo (the dark gap).

 The rocket-like looking things in the picture are specially constructed drifters that are designed to float through the surf. What makes them special is that they've got little GPS devices attached to track where they go. We also attached GPS to volunteer swimmers and floaters who would either jump in the rip and just stay afloat or swim parallel to the beach.

What happened? Most of the drifters went out in the rip and then curved around and came back in towards the beach across the sandbar, completing a circle. Some of them just kept going round and round. The swimmers who just stayed afloat all ended up being carried onto the sandbar safely. The swimmers who swam parallel all swam out of the rip easily. Debate? What debate??? Both options worked!

 The thing is, this was a controlled experiment and the waves were actually pretty big and were closing out when they broke offshore, trapping everything inside. The swimmers were all competent swimmers and everyone knew what was going on. We're trying to expand the experiment into a much bigger project depending on the outcomes of a funding application.

Thanks to all the amazing volunteers who helped out on both days and to SLSA for making it happen.

An armada of GPS rip current drifters