It's the deepest, darkest and, one of the most hostile and quietest places on earth. To get a sense of its depth, if the Mount Everest were to be scooped up and dropped into this hole, it would disappear without a trace. Ever since the British oceanographic ship, HMS Challenger, first measured its depth at roughly eight kilometres — though highly inaccurate by the current measure — in 1875, the Mariana Trench has held a powerful sway over the imagination of adventurers, explorers, and marine scientists.
It took 85 years since its discovery for the first dive to the bottom in 1960, and another 52 years for the second person to plumb its depth. But it all changed in 2018, following the commissioning of Deep-Sea Vehicle, Limiting Factor, developed by Florida-based Triton Submarines. Since 2019, after its pilot, Victor Vescovo, made a solo dive to the bottom of the trench, the former US naval intelligence officer has chaperoned 14 more people into the depth of darkness.
In early March, Dubai-based British national Hamish Harding successfully attempted what no one else had achieved before. He set the record for the longest time of spending 4 hour 15 mins at the bottom of the Mariana Trench while traversing a horizontal distance of 4.6 km.
Both of which are set to be ratified by the Guinness World Records. Ask Harding why he undertook the perilous dive into the watery world, he echoes the immortal words of the legendary ghost of Everest, Irvine Mallory: “Because it’s there.”
But for Harding, it was more than some eccentric indulgence; he wanted to collect samples of water and organism to study the impact of micro plastic pollutions in the world’s oceans.
Located approximately 365km off the nearest airport in the US protectorate of Guam, the Mariana Trench is 10,925 metres below the ocean’s surface at its deepest point, Challenger Deep in the Eastern pool, almost 2,550-km long and 69-km wide.
At that depth, the pressure of the water column is a mammoth eight tonne per square inch or 1,072 the atmospheric pressure. “You are protected from this hostile world by a 90mm titanium shell of the Limiting Factor. It’s currently the only reusable submersible in the world that has made the Mariana Trench dives possible,” explains the aviation entrepreneur, who buys and sells business jets. “The submersible is completely battery operated. It goes down under the weight of bio-degradable ballasts, but to move horizontally or to ascend it uses the thrusters.”
During the course of the 12-hour dive from surface to surface, Harding witnessed many fascinating aspects of the watery world. “You see fishes and other forms of marine life until 300m and sunlight up to 1,000m. Then it goes all dark,” says Harding.
Contrary to lay perception, the bottom of the trench is marked with numerous jagged features. In fact, Harding and Vescovo encountered a rocky feature of the size of the Table Top mountain in Cape Town.
“It was not mapped on the underwater charts, so we had to climb up the side of the mountain using thrusters to cross it before descending again,” said Harding.
The discovery of a certain type of marine life form was the most revealing aspect of the dive. For any life form to survive in that hostile world, the evolution engine ought to be reversed. “We saw shrimp-like creatures at the bottom. But they have hollow structures, possibly
for the water to pass though their bodes to equalise the pressure. We managed collect some samples, which we have sent to the Newcastle University for scientific study along with water samples,” showed Harding over a video call, holding up a test-tube bottle with a “unhappy” unidentified Crustacean specimen.
On extreme expeditions, that x-factor of something or anything going wrong is always a possibility. Even before commencing the dive, one of the thrusters of the Limiting Factor malfunctioned, while on the way down another thruster suffered a glitch. “We were confident that we would be able to complete the mission on eight functioning thrusters,” he said.
Everything that the small submersible carries down is precisely weighted; it means very little food or water. Besides, there are no toilets inside the DSV. “You have to dehydrate a day prior to the dive to reduce weight, and at best you can carry a sandwich and a small bottle of water, which you have to use very sparingly during the dive.”
The submersible is operated from a repurposed mothership called Deep Pressure, which is manned by a crew of 35 people onboard. It maintains communication with the mothership using an acoustic modem that pings with the receiver at 20 bits per second.
On this expedition, Harding was accompanied by his 13-year-old son, Giles, who was managing his social media in real-time from the ship. “He has been with me on my other expeditions. It helps to gain valuable exposure beyond studies. When he was 12, he accompanied me to the South Pole; possibly the youngest person to do so,” said Harding.
* The Limiting Factor has changed the paradigm of deep-sea diving. The earlier submersibles became unusable after one dive to the bottom of the Mariana Trench. In 1960, US-Swiss expedition commanded by Don Welsh and Jacques Piccard were the first persons to reach the bottom of the Western pool in submersible called Trieste that was designed by the Swiss and built in Italy. The duo spent a mere 20 minutes at the bottom before they were forced to ascend
* After the first dive, no man ever fathomed the bottom of this part of the Pacific Ocean for 52 years until 2012 when the Titanic movie director, James Cameroon, performed a solo dive in a submersible called Deepsea Challenger. This vessel too could be used only once and never returned to sea
* This is where the state-of-the art Limiting Factor stands apart. It’s 90-mm titanium shell can withstand 8 tonne per square inch pressure without suffering damage. It’s equipped with precise navigation and communication equipment that makes it one of its kind DSV in the world