The Second Attempt
After we returned from Yongle Atoll, we set about collecting information and data, looking for anything that we could find on the formation of blue holes. We hoped that such information would be useful for our next expedition to Dragon Hole.
Actually, as underwater photographers, we were no strangers to blue holes. In 2005 we explored Dahab Blue Hole in Egyptian Sinai, and in 2006 we visited, several times, Palau Blue Hole. However, our experience in Dragon Hole has woken up in us that very human desire to see the unknown, to explore something that no other man has seen before you.
In April 2013 we returned to Yongle Atoll again, for another chance to explore Dragon Hole, but because of time constraints and issues with low tide, we only had one opportunity to dive. This time we were
We soon found it, at 35 meters. Having fixed the guiding rope, we entered the cave, and staying on its left side, we soon reached the end. We turned back, along the other side of the cave. Despite the large opening, the cave was not deep and there was no cave system, it was just a single dead end tunnel. We felt let down, it was not supposed to be like that, but, pressed for time, we had to accept our disappointment and having taken a few basic shots, we called it a day.
Much later, when we were going over the material that we had shot on the two trips to Dragon Hole, we suddenly realized that those were actually two completely different side caves! The question that arose then was, how many such caves Dragon Hole could contain, and what mysteries might be hidden in their depths?
depth, the stronger are the effects of narcosis, and just like under the influence of alcohol, the diver’s field of vision narrows, judgement becomes clouded and his actions become uncoordinated and clumsy. However, with time, a diver becomes used to operating under its effects.
At fifty meters the diameter of the hole widened a little, but not as much as we had expected. Karst caves and the many blue holes that we had previously explored, all exhibit a relatively small entrance with the body of the cave then widening as you go deeper, creating a bell-shape. We failed to observe anything like that in Dragon Hole, but could it be simply because we have not reached a critical point along its depth?
After spending eighteen minutes exploring at the depth of 64 meters, we started to slowly go up, but when we reached 37 meters we suddenly noticed an entrance to a cave. Could it be yet another one? Still affected by nitrogen narcosis, this discovery got us very excited. In the lights of our torches we could see that the walls of the cave had the classic “fish scale” structure, and were also covered by a thin layer of white sediment, which even our faintest movement
would dislodge and make float around, like strands of white fog in the clear water. Then, in the interior of the cave, we spotted two entrances, and a beam of faint light projected out of one of them. Driven by pure instinct, we started to swim down, towards that light, completely forgetting that we were supposed to be in the middle of a decompression ascent. The passage was narrow, but short, and soon we squeezed our way through it, finding ourselves in the main chamber of the cave. We were already at 42 meters, and so had to immediately readjust our situation according to the new circumstances and continue on our decompression ascent. Finally, after fourteen pauses at different depths of the total duration of 35 minutes, we safely reached the sunlit surface of the sea.
That cave that we discovered during our third dive had another surprise up its sleeve — it was later confirmed that it was the very cave that we had seen during our first dive in Dragon Hole. We saw it as a little joke the blue hole played on us.
We were not the only people who got to explore Dragon Hole. A team of ecology and environmental protection experts sent by Sansha City undertook a series of studies of Dragon Hole between August 2015 and April 2016. Employing underwater robots, the team measured the maximum depth of Dragon Hole at 300.89 meters. In addition, they made a scan of the cross-section of the hole using sonar and took samples of water, microorganisms and minerals for