Thailand – Australia – United Kingdom

OCEAN EXPLORATION ADVANCEMENT

By Robert Lamb

People have plunged into the water for food, valuables and a better understanding of their environment for thousands of years, but even the most skilled divers have their limits — the record for a skin diver is 417 feet (127 meters).

Chafing at those limits, humans have dreamed of underwater vehicles and improved diving apparatus for ages. Plato, Aristotle and Leonardo da Vinci all wrote about underwater exploration. In fact, early swimming goggles, made of wood and thin slices of shell, date back to at least 14th-century Persia.

Treasure Spurs Sailors to Sea

Diving for sunken treasure has long been a driving force behind the evolution of underwater exploration. When you think of Spanish galleons transporting fortunes in gold and silver during the 1600s and disappearing beneath the waves for anyone’s taking, it’s easy to see why.

The Spanish Crown and the Dutch East India Company, both major players in 17th- and 18th-century international sea trade, offered rewards and percentages on salvaged riches. To take advantage of these incentives, investors pooled their resources to fund recovery expeditions. Whoever had the best underwater technology had the advantage. Given the rewards involved, inventors were willing to test many new technologies.

The Diving Bell and the Steampunk Robot

Some inventors simply tweaked the diving process. In 1690, Edmond Halley (of Halley’s Comet fame) patented the first diving bell. It allowed divers to work from a see-through, submerged, enclosed hemisphere of air on dives of up to 60 feet (18 meters) without surfacing for 90 minutes. Oxygen piped down from above made this feat possible. Modern bells allow divers to work at depths of 1,000 feet (305 meters).

Other technologies amounted to early submersibles, such as John Lethbridge’s 1715 “diving engine.” The wooden barrel body featured glass eyeholes and leather gauntlets for the diver’s hands. The invention resembled a steampunk robot and allowed a diver to work for 30 minutes at depths of 60 feet.

Under Pressure

All that progress came with a price: Deeper water means greater water pressure. As the pressure on a diver’s body increases, more oxygen and nitrogen dissolve in the bloodstream. If you rapidly ascend to the surface, the nitrogen forms bubbles, blocking tiny blood vessels. This condition is known as the bends, or decompression sickness. It can result in joint pain, ruptured blood vessels in the lung, heart attack, spasms, paralysis and stroke.

The bends remained a common condition for divers up until the early 20th century, when a better understanding of the affliction led to improved protocol. Regardless of medical knowledge and modern technology, compression sickness remains an occupational hazard for underwater explorers.

Waiting for Cousteau

Piping compressed air down to divers proved effective, but it kept underwater explorers tethered to the surface. To overcome this, divers needed to bring their air supply down with them. Centuries of invention and research eventually led to the self-contained underwater-breathing apparatus, or scuba.

In 1943, Jacques-Yves Cousteau and Emile Gagnan developed the Aqua-Lung. Redesigned from a common automobile regulator, this device provides compressed air to a diver at the slightest inhalation. Modern developers continue to fine-tune this technology, for example, by replacing divers’ oxygen supplies with an enriched blend of oxygen and nitrogen called Nitrox.

Alvin and Zeus

Unlike divers, submersible operators typically don’t have to worry about the bends. Once you move below depths of 1,312 feet (400 meters), diving with pressurized air becomes a moot point. Instead, humans have to bring hospitable air pressure down with them by way of submersibles. The disadvantage, however, is that submersibles require heavy-duty materials to prevent excessive outside pressure from crushing the lower air pressure on the inside.

Today, we’ve not only developed such groundbreaking manned submersibles as Alvin, which can operate at depths of 14,764 feet (4,500 meters) for two hours at a time, but we’ve also developed remotely operated vehicles (ROVs).

For example, the unmanned Zeus II can explore depths of more than 8,200 feet (2,499 meters). Other work-class ROVs can venture up to 19,685 feet (6,000 meters) below the sea. However, they haven’t eliminated human occupied vehicles yet. Work is under way to develop a new replacement human occupied vehicle that will allow divers to pilot an Alvin-like craft down to depths of 21,326 feet (6,500 meters).

Oil Saves the Day

As always, intense water pressure and low temperatures pose challenges for underwater exploration, but the rise of offshore oil drilling has increased demand for high-performing underwater technology. As technology improves, savvy human explorers are able to explore shipwrecks that have lain beyond our reach for centuries.

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