Only three men have ventured to the deepest recorded point on the surface of our planet.
Movie director and ocean explorer James Cameron joined that exclusive club March 26 when made the first successful solo dive – the only human being ever to do so – to the bottom of the Mariana Trench, almost 36,000 feet below the surface of the south Pacific.
It was the first manned dive to the bottom of the trench since 1960 when U.S. Navy Lieut. Don Walsh and Swiss oceanographer and engineer Jacques Piccard crewed the bathyscaphe Trieste.
To descend and return safely from the crushing, cold depths of the trench, Cameron relied on a carefully selected team of engineers, which included Tim Bulman, owner of Nanaimo-based Indepth Marine.
Bulman, 42, is an electrical engineer, commercial diver and submersible pilot/technician with 14 years experience working with manned submersibles and deep-ocean remotely-operated vehicles.
Bulman moved his company to Nanaimo in 2003, the same year he met Cameron and was hired to rebuild lighting control systems aboard two Deep Rover submersibles purchased from a French film company and used to film the documentary movie Aliens of the Deep. When the aging electronics proved unreliable, Bulman established his credibility by retrofitting the submersibles with new lighting controls that worked.
In the world of manned submersibles, reliable people and equipment get recycled. Someone always knows someone else from previous projects. The same people often work on and retrofit existing craft and technological innovations in the business are frequently the result of modifying or rejigging existing technology.
In 2004, while working with Cameron's team on a Discovery Channel documentary about the Titanic – Bulman worked on fibre optic data links for remote controlled submersibles that probed the interior of the wreck – Cameron invited him to work on the DeepSea Challenge.
"In manned submersibles, it's a pretty small network of people world-wide, so when [Cameron] bought the subs from France, he had mostly Americans working on [the project] and I'd worked with most of them before on previous jobs," Bulman said. "So when they needed electronics help, they'd call me up and ask if I was available. It was all word of mouth and then, once it worked for him, then he phones back and asks, 'are you available for this one?'"
Getting equipment to function reliably at enormous depths and pressures presents daunting engineering challenges.
Bulman was hired to work on the communications systems between the Deepsea Challenger, the submarine Cameron would pilot to the bottom of the trench, and the surface support craft.
Bulman worked remotely on the project for months before he joined the team full-time in Australia in November as a subcontractor to Cameron's California-based company, Light Storm Entertainment.
The communication system Bulman worked on was completely new.
"Nobody had a system that would work 11 kilometres deep," Bulman said. "They didn't exist."
Much of the challenge in rigging the communications was in making it work for the application.
Most long distance underwater communication is done with sound, not radio transmissions.
At a depth of 11,000 metres, Cameron would pilot a submarine as far below the surface of the Pacific Ocean as most airliners fly above it, but at the bottom of the Mariana Trench, the pressure on the sub's hull is 16,500 psi. Even water and oil, both considered incompressible, compress under such extreme conditions.
The Deepsea Challenger's communication system relayed data about water pressure to calculate depth, oxygen and carbon dioxide percentages of the air inside the sub's hull, temperature, battery voltage and compass headings. That information was transmitted in low-frequency data packages that to the human ear sound something like the old telephone modems once used to connect to the Internet. The system also handled verbal communication and text messaging.
Sound travels fast under water, but signals quickly become lost among noise sources in the ocean – such as rain, wind, waves, sea life, geological disturbances and, especially, noise from mechanical systems aboard the support ship – so any sound transmitted over long distances has to be loud.
As if getting anything to work reliably under crushing pressures isn't enough of a challenge, Bulman had to tease the sub's signals out from the background din and keep the data transmissions isolated from the voice communications so they wouldn't deafen Cameron, who was listening intently over headphones.
"We had two modems," Bulman said. "One was primarily voice comms and the other was sending data. Every time the data was blasted, it would blast him too because he was listening over a real high gain receiver. It's equivalent to somebody speaking from a mountain top with a megaphone and having someone 30 kilometres away listening for that sound."
Bulman built the bandpass filters that isolated data communications from voice transmissions and limited the discomfort for Cameron. Once built, those filters had to be proofed against the extreme pressure of the ocean.
"Most of the electronics that were external, we just tried to oil fill to be pressure tolerant," Bulman said. "We had a 30,000 psi test chamber in Australia, so we cycled a lot of things to death, to learn where they'd fail."
If a component, such as a battery, failed after 50 pressure cycles, but only 25 dives were scheduled, engineers planned for that equipment attrition by bringing along enough spares.
Much of the equipment was shaken out during test dives off Papua New Guinea, an area Bulman said had not been dived before.
"That was incredible," he said. "The scenery underwater was unbelievable. Within four kilometres offshore you'd be in 8,000 metres of water. We got some really good footage off of New Guinea."
Video footage from test dives and the dives made in the Mariana Trench could contain valuable scientific information, but no one will know for sure until the footage, sea floor samples and other data gathered is reviewed and catalogued. The footage and data is also being compiled into a documentary about the expedition.
One reason the Mariana Trench has not been visited by manned expeditions in more than 50 years is because the world's militaries and oil companies perceive little if any military or monetary benefit from researching the area.
But scientist have dropped landers – glass spheres carrying cameras, LED lights, batteries and bait to attract wildlife – into the trench. Landers hover near the sea floor, tethered on weights for several hours before timers drop the weights and they return to the surface with their data.
In lander video footage Bulman viewed, he could hear the glass sphere beginning to crush.
"Wow, that's really eerie and it really plays on your mind if you're going to be getting into a sub," Bulman said.
Even a small lander imploding under high pressure can set up a shock wave as devastating as a depth charge, so Cameron did not allow landers to accompany the DeepSea Challenger on his dives.
Heavy weather compounded the technical challenges of the dives. The expedition was originally scheduled to take place in November and December when the weather off the Mariana Islands is good, but it was March when seas in the area are rough, before the team was ready to make the dives.
Waves of three to five metres and 25 knot winds prevented dives, but when waves settled down to about one metre and winds died to 10 knots, the sub was launched. When Cameron and the sub returned to the surface, the crew had to recover them regardless of the weather conditions. The grueling schedules and physical conditions of the dive were exhausting.
"It was rough," Bulman said. "Lots of people were seasick."
Cameron, known for being a demanding boss, managed two dives into the trench, the first at 4 a.m. March 26.
Ten lander dives were also made, before the crew was worn out and parts attrition brought an end to the exhibition.
"He pushed hard, but it wouldn't have happened if he had not pushed that hard," Bulamn said.
Another expedition to the trench is planned, possibly within the next two years.
After being gone for six months, Bulman says he has a big "honey-do" list to catch up with at home and he needs to spend time with his family.
He wants to return to the Mariana Trench, but he'd like to do some exploration in the Arctic, diving with and filming wildlife. He also wants to film and survey shipwrecks in the Inside Passage around Vancouver Island.
Bulman also has a short job coming up in mid-May, working with E. James Dixon, professor of anthropology with the University of New Mexico, to look for signs of ancient civilizations of the coast of Alaska at depths of 90-metre, which was the level of the ocean approximately 10,000 years ago.
"We'll go down and get video evidence and maybe some rock samples," Bulman said.
Sidebar :
- Deepsea Challenge sponsored by National Geographic and Rolex
- To learn more about the DeepSea Challenge, please visit the expedition website at www.deepseachallenge.com
- The Marianas Trench, lies east the Marianas Islands in the south Pacific Ocean. Its deepest point, called the Challenger Deep, lies 11 km below the ocean surface
- Don Walsh, who made the only other manned decent to the bottom of the Mariana Trench with Jacques Piccard in 1960, was an member of James Cameron's team aboard the expedition support craft
- The Mermaid Sapphire was the main support ship for the expedition