Defensive swimming conserves energy. Basically float on your back and use backstroke techniques to navigate to shore. Keep your feet on the surface and use them as shock absorbers to bounce off rocks. If you are about to go over a large drop or falls, curl into a ball so your feet don't hit the surface first and potentially become entrapped. It is important to grab breaths of air when available. If you are heading into an exploding wave, over a drop, or into a hole - grab a deep breath before getting submerged. The laid back position is perfect for holding on a throw rope as well.