The guys in the boat are presumably from the Big Bay Life Saving Club, located about 100m to the left of where I took this photo (close to all the restaurants at Eden on the Bay). I presumed that they may have been warning the surfers of some unseen danger - perhaps a shark. The only confusing part was that the surfers looked far too calm - leading me to wonder exactly what the life savers were doing!
While visiting their website I came across an interesting article on rip currents, how they work, how to identify them, and (more importantly) how to escape them. I've always heard that in the event of being caught in a rip current that you shouldn't try to fight against it, but rather swim along the shore until you escape it. Read the article, take a look at the pictures, and familiarise yourself with the technique - it could save your life. :)