Buoyancy

As in:

The ocean was the reason Solly didn’t turn the boat around and insist that Reme finish the job with the shotgun. The Bluefin proceeded southward, until it was a dot and less. Ben felt relieved at no longer being Reme’s prey, but it was only a few minutes later that he inexorably began to feel and prepare himself for the eventuality that he would die out here. 

The immediate choice was not between sinking or swimming, but between swimming and floating. Wet pants are an effective life preserver, if you tie the legs together and blow air into them. But pants are a real drag on swimming. 

Decision one. He would go down swimming. He ditched the pants.

He swam for ten minutes, then let himself come to a stop. Would it be fatigue? Would it be an oceanic white tip shark?  If it were fatigue, what would be the last thing he’d remember? If it were the shark, would he feel terror, or relief?

Uncle Boone had told him about the time he’d gotten a flat tire on a barely traveled highway between Winnemucca and Tonopah out in Nevada. You wouldn’t want to experience that kind of loneliness, he told Ben, but he was grateful that he had, for the images, soundscape and memory of the beautiful desolation he experienced.

And now that was a lot like this, Ben thought. Only this was much wetter and it was becoming a labor to breath. He began his survival floating technique, using the buoyancy of his inflated chest to keep him on the surface while he rested, face down, for the next effort to grab a breath. His oxygen deficient brain began to struggle between stark despair, and boredom. 

As his energy began to wane, he was sinking deeper into the ocean between the strokes he needed to rise for air. It was at the low point of one of these cycles, that his toe made contact with something.