Sand Tigers

by Howard Hall

   The ground was as flat as a dry lake bed, but it was hardly dry. One hundred and twenty feet beneath the Atlantic I knelt down and scooped up a handful of the course sand. Sifting through it, I found two gleaming white fangs. Sand tiger shark teeth. Looking up, I could see three or four sand tigers hovering in the distance. They were motionless, strangely suspended four or five feet above the bottom. Scientists say that sand tigers gulp air. Apparently, the sharks swim to the surface and swallow enough air to give them neutral buoyancy after struggling back down to the bottom. Descending while fighting enough positive buoyancy to make a shark neutral at one hundred and twenty feet seems unlikely. But nature doesn't consult logic. It just goes with what works. Watching the sand tigers hovering motionlessly above the bottom, it was obvious they dealt with their buoyancy problem differently than other sharks.

   I wanted to move closer to the sharks. The 16mm movie camera I held compelled me to sight through the lens, to pull the trigger on something. Time was wasting. My nitrox computer read 2 minutes of no-decompression time remaining. But I was stuck here. Bob Cranston had tied off our movie light cables to the bow of the shipwreck, Papoose, and after moving a hundred and fifty feet away from the wreck I had run out of slack. I could go no further without dropping the lights. But I needed the lights, not only to add some color to this monochromatic world, but also to find my way back to the Papoose and then to the anchor line of the dive vessel, Olympus.

   Bob had gone ahead with his camera in an attempt to film the large school of sand tigers that we thought must be out there. I strained to see light reflecting from the fiberglass shell of his rebreather as he moved away, but it had vanished. Now all I could see were the sharks and the inevitable phantoms my mind creates when straining to see something beyond the steel-gray limits of visibility. Bob was gone. I looked down at my computer. The display had changed. Ten minutes of decompression time.

   I shined the lights in the direction I had last seen Bob. I hoped he could see them and the light would guide him back. Damn, he knows better than to swim out of sight of the lights or the wreck. George Purifoy, owner of the Olympus Dive Center and the boat we had chartered, had warned us that magnetic anomalies produced by the wreck make compass navigation dangerously unpredictable. If Bob gets lost out there, it means open-water decompression forty miles from nearest land and in rough seas. If anyone in North Carolina could find him drifting at sea, George could. But even George would have to get lucky. The sharks continued to hover in the distance. My computer read twenty minutes of decompression now. This was our second dive of the day and the last dive of our expedition. Decompression time was adding up fast.

   A phantom became a sand tiger moving slowly toward me. As it got closer I could see it was surrounded by a school of tiny silver fish. This was one of the behaviors I had wanted to film. For some reason, these sharks are often accompanied by dense schools of baitfish. Perhaps the fish clean up after the shark ungracefully dines. Or, ironically, the fish may stay close to the shark for protection from jacks and other predators.

   As the shark approached, I held my breath. Then I caught myself and began breathing slowly again. Nearly thirty years of holding my breath every time I approached a fish with a speargun or (later) with a camera had formed an unbreakable habit. Once again I tell myself, "You don't have to hold your breath with a rebreather, dummy." Still, I catch myself doing it every time a subject is near. At eight feet away, the movie lights began to reflect from the tiny silver flanks of the schooling fish as they darted about the shark's gills. Through the viewfinder I could see the light begin to gleam on white fangs. The school of tiny fish was so dense it was difficult, at times, to see the shark's face. The camera was rolling. For the moment, I had forgotten about Bob. I had adopted a commercial fisherman's mentality. I was gettin' 'em, and nothing else mattered.

   Suddenly the shark lifted its head and shook its entire body. The violent maneuver was nearly identical to that of a dog shaking off the remains of an unwanted bath. The tiny fish exploded away. Then the shark bolted in the opposite direction at warp speed. The school of fish dashed away in pursuit. In a moment they were gone. I couldn't tell if the baitfish had been able to catch the shark or were left behind to confront the jacks. I turned the camera off and looked down at my focus and aperture setting while silently reciting the cameraman's prayer, "please lord, save me from having screwed-up." Then I looked down at my computer. Thirty minutes of decompression now. Where was Bob?

   A movement caught my eye and I turned. Bob was approaching from a direction nearly opposite where I had seen him disappear. I immediately knew what he had done. He had circled away from me while keeping the dark shape of the Papoose's bow dimly in sight. Then, his survey complete, he followed the light cables out to my location. It was exactly what I would have done. I never doubted him for a minute.

   I showed him the nitrox computer. We had been down thirty-five minutes and had forty minutes of decompression including a ten-minute stop at twenty feet. Bob signaled that we should return to the wreck.

   After a few minutes of swimming, the hull of the Papoose materialized becoming a dark reef in the distance. Swimming along the hull, we passed the huge hole made by the German torpedo that had sent the Papoose to this Atlantic graveyard. A few minutes later we approached the bow where our light cables were tied off. I checked my gauges and my computer. Sixty minutes of decompression.

   The bow of the Papoose was surrounded by a dense school of small snapper and several sand tigers were circling through the schools. Bobby Purifoy was waiting perched high on the inverted hull wearing enormous twin tanks. I motioned him to follow as I swam to the very tip of the collapsed bow. Then I sighted through the lens at Bob, decided it was a good shot, and passed the camera to Bobby. The last shot I needed was a scene of Cranston and I working together. Bobby had been promoted from amateur videographer to prime-time underwater film cameraman. Before we made the dive I had taught Bobby everything he needed to know to make the transition.

    "Point the camera at a spot somewhere between Bob and I." I said. "Then turn it on and hold it still."

   "That's all?" Bobby asked.

   I thought about it for a few minutes reviewing all I had learned from twenty years of underwater camera work; all the great camera moves I had tried, all the artful zooms, pans, and tilts.

   "Yup," I said. "That's about it. Did I say, 'Hold it still?' Well then, that should do it."

    After passing the camera to Bobby, I swam back down to take a position near Cranston. As the sand tigers passed through the schools of snapper, repeatedly parting them like a silver curtain, Cranston took a few last shots. A shark passed between us and swam directly at Bobby, passing less than two feet from his head. The running light on the camera confirmed that Bobby was rolling on the shot and I noticed that, while his neck got shorter, he held the camera rock steady despite being somewhat concerned that the shark might decide to make a snack of his left ear. Perfect. Bobby was a quick study. I suppose I'll have to give him a film credit now.

   Bobby passed the camera back to me as he swam by on his way to the decompression line. He had been down twenty minutes and would do another fifteen or twenty minutes of decompression. As he ascended, Cranston and I took a last look around this beautiful North Carolina shipwreck and at the magnificent sand tigers that lived here. Then I showed Bob the nitrox computer and we agreed that it was well time to go. We had been down sixty-five minutes and had racked up ninety-seven minutes of decompression.

   A few minutes after we reached our thirty foot decompression stop, I saw a great splash as George tumbled into the water with his twin 100s, a scooter, and a crowbar, and swam down to enthusiastically pick through a wreck he has dived a hundred times before.

   I looked up and noticed that the sky was prematurely dark and that rain was pounding the surface. Then I looked down at my gauges. Only ninety-five minutes of decompression to go.