Last year I had the opportunity to tour the 274′ R.V. (research vessel) Atlantis and its famous submersible Alvin while it was docked in Astoria. Alvin is probably the best known craft of its type in the world, having appeared in numerous TV programs making ground-breaking discoveries—several of them off the Washington coast. Peering down through the entry hatch to the cramped space where the operator and two scientists sit for many hours, inspired me to learn more about underwater research craft and deep sea exploration in general.
The Alvin is the only deep-diving manned submersible in the fleet of 15 American deepwater research vessels. It is 23’ long, weighs 16 tons, has an operating depth of 15,000 feet, and carries a pilot and two scientists in the 7′-diameter pressure sphere. It is powered by six reversible electric thrusters, three to move it backward and forward, two for up and down movement, and one for turning. This combination lets Alvin’s skilled pilots fly the sub through rugged sea floor topography, hover, or come to rest on the bottom. The cruising speed is ½ knot, full speed 2 knots, range 3 miles.
The Woods Hole Oceanographic Institution (WHOI) of Massachusetts manages the sub’s research program in tandem with that of its mother ship the Atlantis. They started using the name Alvin for the sub to honor the prime mover and creative inspiration for the vehicle, Allyn Vine. The Alvin has made nearly 5,000 dives since 1964; the craft I saw is actually the latest version of a much-changed platform that gets frequent technical updates. One recent addition is a bigger cargo basket that can carry up to 1,500 pounds of tools and sea floor samples.
As you would imagine, the procedures are focused on safety, because there is no way for the occupants to escape once the hatch is closed. The Alvin is completely disassembled every three to five years, so engineers can inspect every last bolt, filter, pump, valve, circuit, tube, wire, light, and battery-all of which have been replaced at least once in the sub’s lifetime. A fail-safe safety system is built into the craft: the ballast weights are held only by electro-magnets, so if there is a power failure, they will automatically fall away and the sub will ascend automatically. The air supply will keep the crew alive for 72 hours.
Because of their low speed, there is no need to streamline submersibles, which basically consist of the pressure sphere on the front, with all the tanks, batteries, ballast etc. aft and open to the elements–and the tremendous pressure. The pilot starts and stops diving by regulating the amount of water and air in the ballast tanks, and by jettisoning expendable steel weights (like sandbags in a hot-air balloon). And finally–in case you were wondering—there is no room for a bathroom facility of any kind in the pressure sphere…
Disaster Strikes in the Gulf a Mile Down!
So this was more or less where I left the story last winter, when other topics took priority. But on April 20, when the Deepwater Horizon rig exploded, everyone I spoke to was asking questions about the situation—and the conditions a mile down at the wellhead. Having spent the last 22 years writing about all types of marine activities, I realized I still knew very little about the basic facts of life below the waves….
I’m sure that many readers casually assumed, as I did, that there had to be some type of manned submersible or extreme diving suit that would permit an expert commercial diver to descend to the wellhead and stop the flow of oil. However, as the most advanced underwater devices and vehicles available tried to fix the leak–and failed–it became appallingly clear that the “best-available” technology was not up to the task.
None of the manned vehicles developed for research was of any use, and indeed, it seemed as if NASA has more control over an explorer vehicle on Mars than the oil industry does over a robot on the sea floor! This motivated me to resume my research, and my first question was an easy one: how deep can you go using diving gear or submarine vessels?
How Low Can you Go?
Every authority on deep sea research stresses that the most important feature of deep water is undoubtedly the pressure. At sea level it is 14.7 pounds per square inch, and every 33 feet, adds another “atmosphere.” The blown-out Macondo wellhead in the gulf is roughly a mile down, which is over 160 atmospheres and translates into a pressure of more than one ton per square inch!
But even at 500 feet, the pressure is great enough to endanger the type of submarine that fought in World War II. A commercial diver can go that deep, but is pushing the limits of safety by breathing a gas mixture, working with very little sunlight, and being subject to many hours of decompression before surfacing. I thought a list would be helpful, but though this seemed pretty basic, I could not one. So I compiled my own from the most reliable sources. I think you will find a few surprises here!
Depth Limits for Divers and Vehicles.
130’—recreational SCUBA divers for 30 minutes
311’—record for free diver with no aids
600’—WWII U-boat (approximate)
837’—record for free diver with weighted sled
1,083’—record for scuba diving
1,600’—safe limit for modern alloy-steel submarines
1,752’—record for saturation scuba diving
2,500’—diver in rigid Atmospheric Diving Suit
5,000’—Macondo blowout in Gulf of Mexico
8,400’—wreck of the submarine Thresher (1963)
10,000′–deepest oil well in gulf of Mexico
14,000’—wreck of the Titanic
15,000’—manned submersible Alvin
21,325′–manned Japanese submersible Shinkai 6500
25,000’—deepest anchorage (Calypso with 1/4” nylon rode)
35,800′–Mariana Trench–Trieste 1960
Trieste II at the US Navy Undersea Museum, Kitsap
The bottom line of the list represents the ultimate achievement in underwater exploration: sending a man to the bottom of the deepest place on earth. This year marks the 50th anniversary of that first and only manned dive into the the six-mile deep Marianas Trench in the south-eastern Pacific by the bathyscaphe Trieste.
I was surprised to find this vessel and its descendants have a strong connection to the Pacific Northwest. The US Navy eventually re-built the Trieste into an improved version called Trieste II, which was re-fitted and upgraded several times. It was finally classified as a “Deep Submergence Vehicle” (DSV) with a new sphere that was tested to 20,000′ and remained in service until 1980.
The Trieste II is on permanent display at the Navy Undersea Museum at Keyport, west of Seattle on the Kitsap Peninsula. And Don Walsh, the navy officer on the record-breaking dive in 1960, is now 80, and living on the south Oregon coast. He is still active in underwater exploration.
The Atmospheric Diving Suit
There is a way for a diver to go beyond 2,000 feet (deeper than any submarine) without taking any of the risks of pressurized diving. it is called an atmospheric diving suit or ADS. The ADS is a fine example of the adage “small is beautiful”–it is literally a ‘submarine you can wear’ and succeeds because it has the smallest surface possible.
The reason that a man-shaped rigid suit can survive where a full-size submarine could not is because the greater the surface area, the harder it is to build a hull to withstand the pressure. The rule applies to submersibles as well: the smaller the sphere, the easier it is to resist the pressure, and the deeper it can go. 7-8 feet in diameter is the maximum practical.
As its name suggests, the ADS maintains interior pressure at one atmosphere,so the diver/pilot never feels the outside pressure. However, it is so rigid, with elaborate pressure joints, that the diver cannot move around without the help of small propellers on the back of the suit and his hands cannot protrude, he operates interior controls in the sleeves that move the external claw-hands. One of the world leaders in this field is Dr Phil Nuytten of Vancouver BC.
In the 1980s, he produced the first modern ADS, the “Newtsuit,” originally good to 1,000′ and now improved to dive to 2,000′. It is manufactured from forged T6061 aluminum alloy, and uses an advanced articulating joint design and can remain submerged for a normal mission of up to six hours. Recently, Nuytten has built a lightweight one-man submersible called the Deepworker that can dive to 2000′, and introduced a lightweight atmospheric suit—the “Exosuit”– with more flexible joints that is designed for depths to 600.’
I have already compared the deep sea to outer space once, and here is another NASA reference that I find useful–the term “inner space.” It was coined in the 1950s to describe the depths of our oceans. More recently it was popularized by researchers like Dr Sylvia Earle, a former chief scientist at NOAA and a popular lecturer. Oceanographers continue to point out that we know more about the surface of the Moon or Mars than we do about the deep-sea floor beyond the coastal shelf. Coincidentally, rocketry took its first great leap forward in the 1930s, which was also when man caught the first glimpse of sea life in the deeps, with the pioneering exploits of William Beebe.
The Voyages of the Real Captain Piccard
To dive deeper, the craft was fitted with a new pressure sphere, manufactured by the Krupp Steel Works of Essen, Germany, in three finely-machined sections (an equatorial ring and two caps). The sphere’s walls were 5 inches thick. It weighed 13 tons in air and eight tons in water The only view of the outside world was through a single cone-shaped block of Plexiglas. Outside illumination for the craft was provided by quartz arc-light bulbs, which proved to be able to withstand the over-1000 atmosphere pressure without any modification.
The descent to the floor of the Challenger Deep–35,800′ down–took 4 hours and 48 minutes at a descent rate of three feet per second. At 9,000 meters (28,000′), one of the outer Plexiglas window panes cracked, shaking the entire vessel. With the vessel creaking and groaning under an immense pressure of 8 tons per square inch (1,100 bars), the two men spent twenty minutes on the ocean floor, but did not have the equipment to film or take samples.
Piccard reported seeing a fish swimming by; the temperature in the cabin was about 45°F. Unexpectedly, they regained the ability to communicate with the surface ship, USS Wandank II, using a hydrophone system—the message took about seven seconds to reach the surface. To ascend, they switched off the electro-magnets attaching nine tons of external iron ballast, and the Trieste began to rise, taking 3 hours, 15 minutes to reach the surface.
In 1963, Trieste located the remains of the lost submarines USS Thresher and USS Scorpion. It was changed, improved and redesigned so many times that no original parts remained. Later versions were all named “Trieste II,” and served with the Navy until 1982. Then, just like the space program, the government turned its attention and resources away from this peak achievement and focused its efforts on research closer to home. Walsh and Piccard remain the only human beings to ever reach that depth. Today, there are no craft in operation anywhere that are capable of taking a man below 21,000 feet.
On Board the R.V. Atlantis
The RV Atlantis frequently works off the NW coast during the summer, visiting Astoria to re-fuel, pick-up supplies, or to change crew or science staff. It is one of a class of five 274′ research vessels (owned by the US Navy ) that includes the University of Washington’s Thomas G. Thompson. The Atlantis was launched in 1997, and is fitted with quiet diesel-electric azimuthing stern thrusters (Z-drives) and a powerful steerable jet in the bow to allow it to remain dynamically-positioned over a dive to within a few feet.
The Atlantis carries 22 crew, 24 scientists and has extensive laboratory space. The Alvin is moved from its hangar to the stern on a special railway track to keep it secure. The sub is lifted up by the giant tilting gantry on the stern and lowered into the ocean. Two certified swimmers release the rigging and other connections and ensure the sub’s safety on the surface.
Alvin’s Adventures
The first great exploit had nothing to do with science, but certainly justified the sub’s cost when it recovered a 1.45-megaton hydrogen bomb lost by an American air force plane off the coast of Spain. In 1967, during dive 202, Alvin was attacked by a swordfish on the bottom at about 2,000 feet. The fish became trapped in Alvin’s outer skin and was brought back to the surface. There was more drama in 1968, when the steel cable supporting the Alvin snapped with three crew members aboard and the hatch still open.
The Alvin hit the water and rapidly started to sink. The three crew members managed to scramble free, but the sub sank in 5000 feet of water. Almost a year later, another US Navy mini-sub found the Alvin, secured a line on it, and the mother ship hauled it up. It was so intact that lunches left on board were soggy but edible. (This incident led to a more comprehensive understanding that near-freezing temperatures and the lack of decaying oxygen at depth aided preservation.)
Needless to say, the Alvin required a major overhaul after that! There have been no major incidents since then, and the Alvin has made a steady stream of discoveries. In 1973, Alvin’s pressure hull was replaced by a newer 2-inch thick titanium sphere 7 feet in diameter that extended the range down to 15,000 feet—the depth of the sea floor off Hawaii and almost three miles down. Four years later, an expedition led by Dr. Robert Ballard discovered and documented the existence of black volcanic vents near the Galapagos Islands at a depth of more than 7000 feet.
Most famously, Alvin was involved in the exploration of the Titanic in 1986, again led by Ballard. The wreckage of the great liner had remained unseen since the ship sank in 1912. A small remotely operated vehicle (ROV) named Jason Jr. was able to enter the wreck and conduct detailed photographic surveys. That expedition had another—and more important—goal: to film the wreck of the USS Scorpion (SSN-589), the nuclear-armed submarine that sank off the Azores in 1968.
Discoveries off the NW Coast
Alvin discovered an entirely new field of oceanographic research off our coast in 1977 when it found the first “black smokers” on the East Pacific Rise. This type of hydro-thermal sea vent consists of chimney-like structures that emit a black cloud with high levels of sulfides. Water emerges from these vents at temperatures ranging from 60°C up to as high as 464°C. Sunlight does not penetrate this deep.
Life is typically very sparse below 1000 feet, but black smokers are the center of entire ecosystems because so many organisms can withstand the heat and able to convert the methane, and sulfur compounds into energy through a process called chemo-synthesis. More complex life forms like clams and tube worms feed on these organisms. Over 300 new species have been discovered at hydrothermal vents.
There is another important reason why we all have a vested interest in ocean-floor research off the NW coast: The Juan de Fuca plate was the source of the magnitude 9 megathrust earthquake that sent a tsunami onto the coast around 1700. This was probably the strongest earthquake to strike the US mainland in the last 10,000 years. The next big quake is likely to occur sometime in the 21st century……
1930: William Beebe—First Man to Plumb the Depths
Although marine scientists had been attempting to study the depths since the early 1800s, manned exploration of deep water only began in 1930, when famed explorer and naturalist William Beebe’s interest in deep-sea exploration led to the development of Otis Barton’s design for a bathysphere. The craft consisted of a hollow sphere of one-inch thick cast steel 4′ 9” in diameter. The sphere was fitted with three-inch thick windows made of fused quartz, the strongest transparent material then available. Electric fans circulated the atmosphere over pans of soda lime to absorb exhaled carbon dioxide.
In 1934, the two men made a record descent to 3,028 feet. What Beebe saw on that trip—and reported with such vividness—was a glowing world of creatures so astonishing that for decades many doubted his veracity. “The clear sea stretched endlessly, and was so full of luminescence that it sparkled like the night sky,” he later wrote. Cavalcades of black shrimps, transparent eels, and bizarre fish approached the descending sphere.
When Beebe used his spotlight to see them, great shadows and shifting patches of light hovered just out of view, leading him to postulate the existence of giant sea creatures in the Bermudan depths. But far deeper are the 37 oceanic trenches around the world, with the deepest found in the eastern Pacific. They are profound, narrow canyons in the sea floor, and scientists estimate that there are at least a million new species to be discovered there.
The First Bathysphere
The first bathyscaphe ((Greek for “deep boat”) was designed by the Swiss scientist Auguste Piccard, and built in Belgium after WW II. The FNRS-2 was clearly a breakthrough as no unwieldy cable was required. But the funding ran out, and the FNRS-2 was sold to the French Navy, who re-built the hull, re-naming it FNRS-3. Professor Piccard and his son, Jacques, went to Italy and organized a consortium of Swiss and Italian sponsors to build a new bathyscaphe–the Trieste.
The new hull was over 50 ft long, It was filled with 22,500 gallons of gasoline, and water to provide buoyancy for the ascent, and made the vessel independent of the mother ship. The crew sat in the 7-foot diameter, 5” thick pressure sphere, attached to the underside. It was fitted out in Trieste, Italy and launched on 1 August 1953, and made the first deep dive at the end of September to 10,392 feet in the Tyrrhenian Sea. The French responded the next year in Piccard’s old design, and reached a depth of 13,290 feet in the Atlantic, 160 miles off Dakar. The Piccards soon discovered that maintenance and operational costs for the Trieste were too high for them to handle. In 1954, they made one dive and in 1955 did not operate at all. By 1956 they were looking for someone to charter the submersible on a long-term basis. Their experimental vessels had flown the flags of Belgium, France and Italy and finally came under the stars and stripes—when the U.S. Navy purchased the Trieste in 1958 for $250,000. Jacques Piccard continued to be the senior pilot.
International Submersibles Go Deeper
It was almost a year before I discovered that Alvin had four foreign cousins who could dive far deeper than 15,000 feet. I had read several national news stories about plans to build a new American submersible, but none had mentioned the fact that France, Russia and Japan have been routinely diving to 20,000 feet for many years. That is unfortunate, because marine science is a truly international field and many expeditions are joint ventures.
The Russian Mir I and Mir II are three-person submersibles with a maximum operating depth of 6,000 m (19,680 feet ). The Mirs were built in Finland in 1987 and are owned and operated by the Russian Academy of Sciences. The nickel steel pressure sphere is 7 feet in diameter, accommodating one pilot and two passengers.
When not engaged on purely scientific missions, the Mirs may be chartered to help foot the bills. They were used by James Cameron to film the wreck of the Titanic and for the 3D film “Ghosts of the Abyss.” They have explored the wreck of the battleship Bismarck with a production team from the Discovery Channel.
A company called Deep Ocean Expeditions even uses the Mirs for extreme vacations. They have taken passengers to a volcanic vent site located 500 miles off the coast of Mexico and 8,600 feet down. There they saw immense hydrothermal chimneys, some reaching five stories tall, and a wonderland of alien marine life like tubeworms, 6-14 foot long creatures living in alabaster tubes.
In 2011, they are offering a trip down to the Titanic with Chief Pilot Dr Anatoly Sagalevitch. Cost for one dive on the famous wreck and all associated services is $40,000 per person. The Mirs have the same depth limit as the French submersible Nautile, built in 1984 with a 7′ diameter titanium -alloy sphere. The mother ship is the 350′ RV Pourquoi Pas? launched in 2004.
The deepest manned submersible in operation, with a limit of 6500 meters/21, 325 feet, is Japan’s Shinkai 6500. It was completed in 1990 with 3” thick titanium pressure hull, and was designed to play an important role in the world’s deep sea research, including geophysics, geology, earthquake prediction, which is vital to Japan, since the Japan Trench generates tsunamis and earthquakes and is 9,000 m (30,000 feet) deep. However, the Chinese are rapidly catching up in submersible design as in most other fields……..
Back to the Bottom of the World
Woods Hole’s new ROV is named Nereus. Its May 2009 dive makes it the world’s deepest-diving vehicle currently in operation, and the first since 1998 to explore the Mariana Trench. It hovered for more than 10 hours over the trench and sent back live video to the mother ship. On the bottom, Nereus collected liquid and rock specimens. Nereus weighs approximately 3 tons in air and is about 14 feet long and 8 feet wide.
Approximately 2,000 lithium-ion batteries provide its power. It is capable of two types of operation: free swimming or tethered with a thin optic fiber cable, operated by pilots aboard the ship. The cable enables it to make deep dives while being highly maneuverable. The optic fiber tether has the approximate diameter of a human hair, and can bear only 4 kilograms (8.8 pounds). It is made up of a thin layer of plastic surrounding a slender glass fibre.
The Son of Alvin…
The design of a replacement for Alvin is the result of more than 10 years of discussions and input from the scientific community. It will feature Increased depth capability, a larger personnel sphere with more larger viewports, more speed and maneuverability, a faster descent/ascent time, more streamlining, and a longer submerged time (8-10 hrs at 8,000 feet). It will also eliminate use of drop weights for shallower dives
So far, two titanium ingots, each weighing 17,000 pounds, have been forged into two hemispheres in a process that requires multiple heat and pressure cycles. An additional 7,000-lb ingot will be used to make viewport and hatch inserts. The two hemispheres will be further heat treated and welded together to make a single three-inch-thick sphere. Recent budget cutbacks mean that the new sphere will probably be integrated into the existing body, continuing the tradition of technical evolution that has characterized these efforts since 1960.
This is certainly a risky and expensive “race to the bottom.” Robert Ballard, the discoverer of the wreck of the Titanic, does not think it is worth the money. “The deep sea has very little to offer,” he said. Others disagree. Sylvia Earle, says the world was at the start of a “second golden age of underwater exploration.”