Manned submersibles: a tool for scientific research?
In March 2012 engineer Ron Allum’s expertise took a man to the deepest point in the world’s oceans – and safely back again. The culmination of seven years’ work, Allum led the project that would plummet filmmaker James Cameron seven miles down to the Challenger Deep, the deepest part of the Mariana Trench in the Pacific Ocean. On a recent visit to the National Oceanography Centre (NOC), Allum spoke about his past, his love of diving, and his sometimes unconventional approach to engineering challenges.
The Challenger Deep is one of man’s final frontiers. Visited only once before in 1960 by Jacques Piccard and Don Walsh aboard the Trieste submersible it offered an irresistible challenge to Cameron, who asked the humble engineer from Australia to get him there.
Designing a submersible that was capable of withstanding the conditions seven miles under, and supporting a human life, is not a task to be taken lightly. Allum gives full credit to Cameron who first came up with the submersible’s sleek, vertically oriented design. Together Cameron and Allum spent years refining the design which incorporated 3D camera systems and a high science capability. It was then Allum’s job to resolve the many challenges the vehicle would face working at full ocean depth. In an interview before his talk to a packed lecture theatre at NOC, Allum said he had no doubt that he could deliver: “Given time, I knew I could solve any issue.”
And so he did.
Piece by piece, Allum systematically addressed one problem at a time, testing each component to high pressures and freezing temperatures. Seven miles down, conditions are extreme – cold, dark and crushing. Any sunlight will have dissipated well over six miles above, the temperature is only just above zero degrees Celsius and, with a seven mile column of water pressing down, the pressure is about a thousand times that at the surface.
One of the biggest hurdles was finding a foam material that would make up the structure of the sub. All of the products already on the market did not have the strength and durability to withstand the extreme environment at seven miles down. Undeterred, Allum thought to himself, “Maybe we can do it a different way.”
“Rather than involving external contractors that might say it wasn’t possible,” said Allum, “I bought a food mixer, and started mixing my own.”
Ron Allum is not your usual suspect to front an expedition to the Challenger Deep. With no formal qualifications, he carved his career as an engineer by following his interests, seizing at opportunities, and tackling engineering challenges hands-on.
Allum started out as a broadcast technician in Australia. It was his love of scuba diving, and then cave diving, that allowed him access to extreme environments, where the scientific processes he observed inspired him into underwater exploration. Whilst he never saw himself as an academic, he worked alongside researchers, designing and building vehicles that would transport equipment and samples in underwater caves.
His move to a documentary film crew established the link with James Cameron, perhaps best known for his films Titanic, Avatar and Terminator – and through this Allum filmed iconic images of shipwrecks the Titanic and the Bismarck from manned submersibles. A seasoned scuba diver by this time, Allum put the 5,000 metre dive to the German battleship Bismarck into perspective: “Within 30 seconds I reached the deepest point I had ever dived – and the descent took another two hours.”
This year’s expedition to the Challenger Deep was a further 6,000 metres down.
James Cameron is quoted as describing the descent as “like being in an express elevator,” because Allum and his team had designed a sub, named Deepsea Challenger, that would travel at 3.6 metres per second, to allow for more time at the seafloor.
Ron’s own experience in the Deepsea Challenger, whist not so deep (1,100 metres), was equally as exhilarating.
“There’s always something to do; the eight hours just flew,” said Allum. “They were telling me to come up but I wanted to stay down there.”
Both Allum and Cameron would have been able to survey the scene on a monitor, captured by a high-resolution camera that gives a 90-degree field of view. And in typical Cameron style, three-dimensional cameras also captured all activity. From a restrained seated position, the pilot can manoeuvre the sub, and when ready to ascend back up to the surface, the 500 kilos of ballast weights are released, tipping the buoyancy balance and allowing the foam structure to shoot upwards.
Not just planting a flag
Scientific observation and sampling of the deep-sea has been revolutionised by the use of underwater vehicles. The National Oceanography Centre’s deep-sea robot Isis, a remotely operated vehicle (ROV), has brought images of the never before seen underwater volcanoes, or ‘black smokers’, in the Caribbean Sea and the Southern Ocean in recent years, and samples of the strange life sustained by minerals expelled from the vents.
So what can a manned submersible bring that cannot be achieved by an ROV? With a very real threat of suffocation, freezing or implosion, why would we choose to expose people to these risks in the name of scientific research?
Allum insists the mission was more than just to plant a flag. It was designed as a ‘proof of concept’ vehicle, to demonstrate that manned submersibles could be used as a science platform. Unfortunately, the scientific equipment on the March mission was flawed, which compromised the samples and measurements taken. Allum put this down to part of the process of designing a new machine: “When designing a new tool, you have to go through testing and revision stages,” he said. “The sub currently operates at 85 per cent, and now needs a re-design to bring it up to 95 per cent.”
Deepsea Challenger will now be made available to the scientific community, and Allum’s view is that with further training and development, the risks will be reduced, and mankind will benefit from the advantages of manned scientific research.
Allum also wants to make the technology widely available so that diving to full ocean depth will be considered more attainable. Reflecting on where this technology is headed, Allum predicted that deep-sea tourism could become commonplace in the future. Drawing an analogy with the space industry, he said:
“I see no reason why eventually manned submersibles can’t be used by the tourism industry. In the same way that soon the number of ‘civilians’ to visit space will outnumber astronauts, trips to the deep-sea will be offered to everyone, and not just scientists and explorers.”
And would Allum be tempted into another deep-sea expedition?
“I’d love to build another sub,” he said, “I’d do so in a heartbeat.”