Shmulik flooded the ballast tanks and the DeepSee submersible began to drop toward the ocean floor. Avi Klapfer, Dave Forsyth, and I were hovering beneath the sub as she began her descent. I raised my RED camera and grabbed a shot of the hull silhouetted against the sun then waited as it fell to the bottom one hundred and twenty feet below. When the submersible touched down, Dave, Avi and I climbed aboard.

Our dive had two purposes. Avi wanted me to capture high-resolution RED motion picture images of the sub as it passed through the canyon-like channel between the Manuelita Islet and Cocos. I wanted to get a feel for how comfortable the sub would be to ride under full thrust. After developing diving protocols that benefit from a synergy between divers and the submersible, I hope to use the DeepSee to transport a team of trimix rebreather divers 300 feet down to a place called The Arch. There I hope to film the elusive ragged-toothed shark.

With all three divers in position, Shmulik hit the thrusters and we powered ahead into the canyon. I was pleased at how comfortable the ride was. I had some difficulty holding the Gates Deep RED housing against the flow. But I realized that on a deep trimix dive, I could tie-off the camera and clip myself in, leaving my hands free to monitor my rebreather instruments. Avi and I were riding on either side of the large acrylic sphere that protected Shmulik and his passengers. Dave was behind the sphere and said there was almost no flow felt there. That would be the best place to tie off cameras and bailout gas for the trip to the Arch, I thought.

After a few minutes moving over the rotolyth-covered sand, I began to perceive the shadow formed by the steep walls of the Channel. Looking to my left I saw another shadow. It was moving. I waved to Shmulik and dropped off the sub with my camera. A large tiger shark was moving in the distance. I would love to get a shot of the submersible with a tiger in the foreground. But as soon as I moved toward it, the shark turned away. Still, I had seen my first tiger shark at Cocos!

During the last twenty years, Michele and I have spent almost 200 days diving at Cocos Island. We’ve have made four films here including an IMAX film called Island of the Sharks. Our last production at Cocos was an episode of the PBS Series, Nature, called Shark Mountain. It aired in 2003. That was Michele’s and my last trip to the Island until now. We haven’t dived here for almost seven years.

We were both very interested to see how Cocos has changed in seven years. Island of the Sharks was made during the most powerful El Nino event in history. Water temperatures soared to over 87 degrees. The hammerheads and many of the large pelagic animals disappeared. The hard corals nearly all bleached and died.

As soon as the 1998 El Nino broke, the hammerheads and other big animals returned. But the coral garden on east side of Manuelita remained covered in algae. It was still largely dead in 2003 when we made Shark Mountain.

Now the hard corals are back at Cocos and seem as large and as healthy as they had been prior to the 1998 El Nino. The return of the coral garden was just one change that has taken place at Cocos since our last visit. Since then something else has changed. Tiger sharks have rediscovered the Island. In all my diving at Cocos I had never seen a tiger shark and had only heard of one sighting since 1990. Now tigers are seen almost every day at Cocos.

Despite no one ever having seen a tiger shark until very recently, tiger sharks are not entirely new at Cocos. Hans and Lotte Hass wrote about diving at Cocos in 1951. When they were here, nearly sixty years ago, they saw tiger sharks everywhere. Something changed at Cocos in the years before Undersea Hunter began supporting dive operations at the Island in 1990. The tiger sharks disappeared. Now they are back.

Avi, Dave, and I moved into the Channel with the current as Shmulik held DeepSee at the mouth. As I moved into the Channel looking for a good vantage point, Avi suddenly pointed high on the Channel wall. A huge tiger was moving into the Channel along the escarpment. I took a quick shot, but was hopelessly late. The animal was already moving away. A few moments later DeepSee entered the Channel and Shmulik skillfully maneuvered the craft between the walls as the current roiled and buffeted the sub. The image looked great through the large RED viewfinder.

As good as the view was of DeepSee passing through the Manuelita Channel, it can’t compare to the view from within it – especially in those shadowy depths beyond the range of divers. Michele and I made four dives aboard DeepSee. Shmulik piloted three of the dives. We dived a seamount called Everest where at 300 feet I saw fish species I have never seen before. The acrylic sphere completely disappears once you are submerged and you find yourself surrounded by the deep ocean. Soaring over Everest we saw silky sharks, yellowfin tuna, and an enormous school of hammerhead sharks.

On our second dive Shmulik took us to the edge of the Cocos plateau. Here, 700 feet below the surface, the sandy plain suddenly ends in a dramatic wall that plunges into the abyss. We descended to nearly 1,000 feet where we saw many bizarre creatures including a three-foot jellynose fish that looked like something out of science fiction.

After ascending the wall, we moved to a place called Piedra. There Shmulik flooded his ballast tanks and settled gently on the sand at 600 feet. A half-dozen mobula rays glided through our lights. We watched as large grouper (a species never seen in shallower water at Cocos) hunted brilliantly colored deep-water reef fish. But the best part was when Shmulik turned off the lights.

There is not much light at 600 feet, but there is enough. It’s like being in the desert on a full moon. The rocks are shadowy silhouettes that seem to come alive in the darkness. Indeed, thousands of fish that had shunned our lights emerged and filled the water around and above us. Many looked into the dome from inches away. Since you can’t see the acrylic, it’s almost impossible to believe you can’t reach out and touch them.

On our final dive aboard DeepSee, Avi piloted us to the Arch. This amazing structure is at the southeast side of Cocos at a depth of 300 feet. Not only is this deep reef covered with spectacular invertebrate growth unlike anything seen in the north, but it is also the haunt of ragged-tooth sharks. As soon as Avi reached the bottom a hundred yards away from the Arch, we began seeing sharks. Some were nearly fourteen feet long with a face bristling with fang-like teeth. Using the remote HD camera in the Gates housing, we captured images of these spectacular sharks as they moved over the deep reef. Seeing them completed my reason for coming back to Cocos Island.

Ever since Steve Drogin built the DeepSee submersible I have been fascinated with the idea developing a synergy between deep trimix rebreather divers and the sub for deep reef exploration. For me, our return to Cocos confirmed the validity of the idea. Using the strengths of both technologies, deep reef exploration can be taken to an entirely new level. I expect that my next trip back to Cocos will be the adventure of a lifetime.