6,000 meters down: Military, nuclear technology supports deep-sea subs

Though the Nautile can't match the submarine envisioned by author Jules Verne and piloted by his fictional Captain Nemo, the French deep-diving sub today is the pride of France.

The Nautile is named after the submarine Nautilus piloted by Nemo in "Twenty Thousand Leagues Under The Sea," the classic science fiction novel by Verne published in the latter half of the 19th century.

In Verne's story, the Nautilus was capable of traveling at speeds of up to 50 knots (90 km) per hour and to a depth greater than 10,000 meters. The Nautile, by comparison, travels at 1.5 knots per hour and can reach a depth of 6,000 meters.

Though it fails to match the speed and depth capabilities of the sub in Verne's fictional world, in the real world, the Nautile's capabilities and performance are highly respected.

At the beginning of May, we visited a research center operated by the French Research Institute for Exploration of the Sea (Ifremer), Nautile's owners, in the harbor city of Toulon on the Mediterranean coast. Since its days as the National Center for Exploration of the Sea (created in 1967), Ifremer has played a major role in deep-sea exploration and currently employs approximately 1,600 researchers and technicians.

Out on a survey of rare earth elements in the south Pacific, Nautile was not at the center during my visit. According to the person charged with its care, Vincent Rigaud, Nautile has made approximately 1,800 voyages since its commissioning in 1984.

"Of those, 90 percent have been for scientific research while 10 percent were missions on behalf of the government," said Rigaud. He added that the Nautile has performed a wide range of missions including recovering the flight recorder of a downed aircraft and searching for sunken ships.

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Though not widely known, the ocean area controlled by France is second in size only to the United States. Possessing overseas territories in areas such as the Caribbean Sea, Indian Ocean and Polynesia in the South Pacific, France prides itself on being a maritime nation.

While the United States and the former Soviet Union competed fiercely in the development of outer space during the Cold War, France was concentrating its efforts on a different frontier, the deep ocean. Accumulating experience over a half century, France established itself as a "Deep-sea Development Superpower" with technology and survey capability rivaling that of the United States in both public and private sectors.

Since the 1950s, the United States and France have been engaged in intense competition to develop the ocean depths. In the beginning, the focus of the rivalry was on how deep a person could dive, with both countries setting records in the 1960s at depths between 9,000 to 10,000 meters. Entering the 1970s, the competition to develop manned submersibles shifted to vehicle maneuverability and how long the craft could stay submerged. With the development of the Sea Cliff by the United States in 1984 and later the Mir by the Russians, underwater navigation at depths of 6,000 meters became possible.

Judging only by depth, it would appear that submersible capability had taken a step backward. However, it makes sense when looked at from the perspective of each nation's intent, namely the exploitation of resources at the ocean's bottom; being able to dive to 6,000 meters means that about 97 percent of the ocean floor around the world can be reached.

Technology being used by Nautile has a connection to nuclear power, a specialty of France. The pressure resistant hull covering the part of the vehicle that carries people is constructed of a titanium alloy. Titanium is hard and difficult to machine. As such, manufacturing technology used in the construction of nuclear reactor pressure vessels served as a useful reference for the French when building Nautile's hull.

Construction technology used for deep-sea submersibles also shares a close relationship with military technology, such as that used in submarines. Nautile was developed by the state-owned ship builder Direction des Constructions Navales (DCN). DCN is single-handedly responsible for the design and manufacture of French warships, and it employed naval technology used in submarines and other warships in the construction of Nautile. One of the missions of the country's deep-sea submersibles is to perform rescue operations should French navy submarines experience trouble at sea.

Invited by Rigaud to take a walk outside, I could see the French navy's largest military base, separated from us by a ferry pier, on the opposite side of the port. Seeing that the navy and Ifremer were also geographically close offered a glimpse into why the Nautile called Toulon its home port.

"The development of Nautile is an embodiment of the state and also carries with it the nuance of being a 'flagship,' " explained Rigaud.

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Other countries are also using manned deep-sea submersible as tools of national prestige.

In 2007, Russia provoked controversy by using the manned submersible Mir to plant its national flag at a depth of 4,261 meters on the sea floor near the North Pole.

"If a robot had planted the flag there would have been no meaning. It is precisely because a human being went there that makes it significant," said Andy Bowen, the director of the National Deep Submergence Facility at Woods Hole Oceanographic Institution.

Japan's manned submersible Shinkai 6500 can dive 500 meters deeper than the Nautile. Why?

Though it is true Japan was fixated on having the deepest diving submersible, in addition to surveying for natural resources, an important role the Shinkai 6500 plays in carrying out research related to earthquakes cannot be overlooked.

"Surveys of the Japan Trench fault, which lies at a depth in excess of 6,000 meters are vital for predicting earthquakes," said Mitsubishi Heavy Industries' Kazuya Inoue, who was involved in the design of the vehicle. "Shinkai was designed (for use at this depth) for reasons differing from those of other nations."

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DEPTH 10,898 METERS: DIRECTOR JAMES CAMERON VISITS DEEPEST PART OF THE OCEAN IN SOLO DESCENT

In March, Canadian-born film director James Cameron caught the public's imagination when he descended to the bottom of the Pacific Ocean's Mariana Trench to almost its deepest point, reaching a depth of 10,898 meters.

Cameron's attachment to the sea is especially strong. Even after the release of his film "Titanic," he carried out detailed surveys of the Titanic's final resting place, visiting the site more than 30 times using the Russian submersible Mir.

Planning for the dive was carried out over seven years. A one-man submersible named the Deepsea Challenger was developed to take Cameron down to the required depth. During the course of its testing, it is said that trouble occurred on numerous occasions.

"To the Ocean's Deepest Point," a National Geographic Channel program chronicling events up to and including the day of the dive, aired in Japan at the end of May. According to the program, Don Walsh, one of the two men who were the first to visit the deepest part of the Mariana Trench in 1960 while crewing the U.S. bathyscaphe Trieste, rushed to Cameron's embarkation point to wish him well saying, "Good luck and have fun."

Plunging into the depths, it took Deepsea Challenger about two and a half hours to reach the ocean bottom.

"I'm in a world detached from society never before seen by anyone. I feel like the loneliest person on the planet," Cameron said.

Though Cameron had started collecting samples, while investigating his immediate environs he experienced problems with the submersible's hydraulic system and other troubles and was unable to move the craft forward. About three hours later he contacted the mother ship and informed them he would be starting his ascent.

After releasing a 300 kilogram weight, the submersible began to rise.

"I felt like I was freed from the shackles of the sea," Cameron said. Seventy minutes later he arrived safely at the surface.