For the past five years, John Rennie has braved the towering waves of the North Atlantic Ocean to keep your e-mail coming to you. As chief submersible engineer aboard the Wave Sentinel, part of the fleet operated by U.K.-based undersea installation and maintenance firm Global Marine Systems, Rennie--a congenial, 6'4", 57-year-old Scotsman--patrols the seas, dispatching a remotely operated submarine deep below the surface to repair undersea cables. The cables, thick as fire hoses and packed with fiber optics, run everywhere along the seafloor, ferrying phone and Web traffic from continent to continent at the speed of light.
The cables regularly fail. On any given day, somewhere in the world there is the nautical equivalent of a hit and run when a cable is torn by fishing nets or sliced by dragging anchors. If the mishap occurs in the Irish Sea, the North Sea or the North Atlantic, Rennie comes in to splice the break together.
On one recent expedition, Rennie and his crew spent 12 days bobbing in about 250 feet of water 15 miles off the coast of Cornwall in southern England looking for a broken cable linking the U.K. and Ireland. Munching fresh doughnuts (a specialty of the ship’s cook), Rennie and his team worked 12-hour shifts exploring the rocky seafloor with a six-ton, $10-million remotely operated vehicle (ROV) affectionately known as "the Beast."
The Beast is like a lunar lander on steroids. Working at depths of more than a mile, it can trundle along the seabed on caterpillar treads or, when its thrusters kick in, skim above canyons like a hovercraft, at a top speed of three knots. Rennie and his team of six control the Beast via a joystick, using its sonar, video cameras and metal detector to locate damaged cables. Plucking a cable from the ocean floor is akin to picking up a piece of thread in a blizzard while wearing a catcher’s mitt. Currents can be fierce, which makes it difficult to hold the Beast steady above the cable. Visibility can be close to nil, which means that even finding the cable in the first place can be a long and frustrating process of trial and error. But according to Rennie, "gripping and cutting is the trickiest." This delicate piece of submarine surgery has to be performed quickly and cleanly, using only a murky video image as a guide.
When Rennie found the U.K.-Ireland cable--fishermen had cut it after it became entangled in a dragnet--the Beast’s manipulator arm grabbed it, sliced it clean, and brought each end to the surface. On board the ship, the cable was repaired and x-rayed (Rennie needed to make sure the splice was set right, as with a broken bone), then tested and lowered to the seafloor. "There is no time for celebration when we fix a cable," Rennie says. "There is lots of pressure from cable owners to move quickly. They are losing revenue."
Most cable breaks go unnoticed by users. Maybe a YouTube clip will take someone a nanosecond longer to download, but that’s about all anyone might notice when a single cable snaps. There are so many different lines connecting so many different places—a map of the network looks like the inside of a baby grand: strand after strand of cable stretching across the ocean floor like so many piano wires that service providers can usually reroute around any break. But if several cables snap in chorus, as they did several times in the past two years, big problems result.Last December 19, when three cables under the Mediterranean Sea were damaged, Internet service began to wink out across the Middle East and parts of Southeast Asia. Egypt suffered terribly, losing as much as 80 percent of its network. E-mail and Web access were disrupted in Saudi Arabia and other Gulf states, while services fluttered in countries as far away as Malaysia and Taiwan. India’s enormous outsourcing industry—the customer-service backbone of the Western world—was also hampered, with the humble fax machine making a brief but crucial comeback until traffic was rerouted around the breaks. The same thing had also happened in January and February, disrupting Internet access to homes and businesses throughout the region for days.
The incidents reveal a surprising fact about the Internet: that it requires constant physical maintenance. Without people like Rennie patching cables, the entire network would gradually stop. First, traffic would slow to a crawl as more bits crammed into fewer and fewer cables. Then, after a while, isolated service failures like the ones in the Middle East would pop up. Eventually, as line after line went dark, U.S. businesses would be cut off from their outsourced functions abroad, international e-mail traffic would halt, and global financial transactions would cease. Pockets of connectivity would persist, but ultimately the Internet we rely on to stay in touch with the rest of the world would be reduced to the local-area network in your office.
On the next page, see our animated graphic of how the web works.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.