IT’S every oceanographer’s dream start to the day. Get out of bed, slip on a
pair of jeans and a T-shirt, then take a lift to the bottom of the sea. No
wetsuits, no submersibles, no decompression tanks, just a permanent trapdoor to
the ocean floor.
Nobody’s throwing away their wetsuit just yet, but a non-profit group of
maritime engineers called the Ocean Technology Foundation reckon they can make
the dream come true within ten years. They’re planning to build a vessel that
will take scientists, divers, tourists or anyone else who’ll pay, to the bottom
of the sea with the minimum of fuss. Exactly how they’ll do it is still a matter
of debate. But one thing’s for sure: the ships they’re designing will never turn
up at your average boat show.
The arguments for sending humans to the bottom of the sea are similar to
those for putting them in space. Remotely operated vehicles and electronic
monitoring equipment can do a good job of gathering data, but there are certain
skills only humans can bring to the job. As yet, machines are no match for
people at learning through observation, solving problems or reacting
intelligently to surprises.
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“Putting people there is really critical,” says Sylvia Earle, former chief
scientist at the US National Oceanic and Atmospheric Administration and a board
member of the Ocean Technology Foundation. James Leichter, a biological
oceanographer at the Woods Hole Oceanographic Institution in Massachusetts and a
veteran of underwater habitat research, agrees. “You can’t replace the value of
actual direct human observations,” he says.
But getting a good look at the deep sea is hard. Scuba diving is complicated
below 50 metres. To go much deeper you need a submersible, but only a handful
exist and trips can only last a few hours. Oceanographers would rather spend
days or even weeks observing the sea floor. For this, they need an underwater
habitat, but there are only two of these operating anywhere in the world. Both
are in the Florida Keys in water only about 18 metres deep—and one is
rather poorly equipped for research because it is a hotel.
Things were very different in the 1960s. The Alvin research
submersible—capable of diving to the deep ocean—had just been
launched and several countries were developing underwater research habitats.
Between 1960 and 1966 the US Sealab programme opened three underwater stations
and by the end of the decade “aquanauts” were undertaking extended missions
nearly 200 metres down. But in 1969 civilian diver Berry Cannon drowned inside
Sealab III and backing for the programmes dried up.
The Ocean Technology Foundation thinks it’s time to pick up where Sealab left
off. One of its founder members, Richard Cooper, now director of the Marine
Sciences and Technology Center at the University of Connecticut in Groton,
logged months on the sea floor as a Sealab director. Ever since then he’s had an
idea for a deep-sea habitat where people could live and work comfortably for
weeks or months on end. About four years ago he and a group of colleagues
founded the Ocean Technology Foundation to put the idea into practice. They call
the project OASIS, short for Ocean-Atmosphere-Seafloor Integration Study.
An OASIS underwater habitat would be very different from the habitats of old.
These operated at the pressure of the surrounding water, as do their modern
counterparts in Florida. Inside Sealab III, which was stationed in 185 metres of
water off San Clemente Island in California, the ambient air pressure would have
been nearly 2 million pascals— about 20 times atmospheric pressure.
The advantage of this was that divers could use the habitat as a base for
excursions without worrying about the bends. Diving or living under pressure
causes the bloodstream to saturate with nitrogen, which isn’t immediately
harmful but can become a problem when you want to return to the surface. Come up
too quickly and the nitrogen forms bubbles in your bloodstream, causing
decompression sickness. To prevent the bends you have to spend hours or even
days in a decompression tank.
If you live underwater, there’s no need to depressurise. But this doesn’t
mean these habitats are convenient. You can’t just drop in when you feel like it
as your body needs time to adjust. Even at 185 metres down, the aquanauts in
Sealab III were a long way from home.
The Ocean Technology Foundation wants to build a habitat that would operate
at normal atmospheric pressure. That would mean easy, dry access from the
surface, so no one would have to take up residence on the bottom of the sea. And
yes, you could go in wearing jeans and a T-shirt.
At first, Cooper and colleagues envisaged a fixed platform similar to an oil
rig, stationed in around 200 metres of water off Martha’s Vineyard in
Massachusetts. Above the surface would be living quarters, laboratories,
classrooms and accommodation for ecotourists. Beneath the waves would be
mid-ocean labs at various depths and a large habitat on the sea floor with labs
and an airlock for divers, all linked to the surface via a lift shaft. This
plan, known as Ocean Base One, is still on the table but has fallen out of
favour, largely because it would have to stay permanently fixed. It also has a
projected cost of around half a billion dollars.
These drawbacks led Cooper’s team to look at ways of doing the same thing in
a mobile vessel, and that’s when ideas took a bizarre turn.
One plan is for a vessel called the Deep Water Flip Ship. On paper at least,
this is a huge, tubular boat that measures 330 metres from bow to
stern—longer than the Eiffel Tower is tall. To get access to the seabed,
the ship first sails to wherever it’s needed and then performs an astounding
manoeuvre. Three huge ballast tanks on the stern flood with water and the rear
part of the ship plunges beneath the waves, pulling the vessel through a 90°
flip. Once vertical, more than three-quarters of the ship is submerged while the
front end, with its cabins, control rooms and helicopter landing pad, sits up
above the water
(see Diagram).
Most of the equipment on board is designed to
rotate so it stays the right way up throughout the flip. “We’re talking about
something about as long as an aircraft carrier that suddenly turns into a
skyscraper,” says chief designer Mark Whitney, a senior engineer at submarine
builders Electric Boat in Groton, Connecticut, who volunteers his services to
OASIS.
The idea may sound preposterous, but a smaller craft that performs similar
maritime gymnastics has been around for nearly 30 years. Dubbed FLIP, or
Floating Instrument Platform, it’s operated by the Scripps Institution of
Oceanography in San Diego, California. FLIP looks like a regular ship with the
stern chopped off and a 100-metre pipe welded in its place. The pipe is
basically one big ballast tank that floods to make the ship tip over. Once
submerged, the tank provides stability so that scientists can park the craft and
get on with their experiments.
Besides being able to perform the same manoeuvre, the OASIS ship would bear
little resemblance to FLIP. For one thing, it’s more than three times as long.
What’s more, its rear portion isn’t just a ballast tank but is designed to
deposit the researchers as close to the seabed as possible while keeping them at
atmospheric pressure. To do this, the hull is a sealed tube which, once flipped,
turns into a lift shaft. Along the length of the shaft are laboratories linked
to the surface by the lift and stairs.
Weighing anchor
The flipped ship could stay in one place for weeks or months at a stretch,
stabilised by the submerged stern and the ship’s propellers. And by varying the
amount of water in its ballast tanks, the crew could control how much of the
ship is submerged. Whitney says the basic design has a depth range of 225 to 275
metres—enough to visit the deepest parts of the continental shelf. A wider
range would be made possible by removing or adding segments to the hull, because
Whitney’s plan calls for the segments to be bolted together rather than welded.
This would also mean specialised labs could be slotted in if need be. At first
this would have to be done in dock, but Whitney hopes it would eventually be
possible at sea.
Pumping the water back out of the ballast tanks would right the craft.
Whitney estimates the manoeuvre would take around 12 hours, as would flipping
from horizontal, but in an emergency the tanks could be blasted out with
compressed air and the ship flipped in about a minute. “It would be a little bit
of a rough ride,” says Whitney, “but the alternatives would be worse.”
The OASIS flip ship, however, has its drawbacks. While cheaper than Ocean
Base One, it would still cost an estimated $200 million. And its depth
range is limited. With these problems in mind, Clifford Ness, a retired Electric
Boat submarine designer and a member of the Ocean Technology Foundation, came up
with an alternative plan. Why not build a massive hinged arm with labs at the
end that could be lowered like a penknife blade from the bottom of a ship?
Since November, Ness has been working on a plan to attach a 200-metre arm to
a disused oil tanker. The appendage would be bolted to one end of the ship and
housed in a hollowed-out compartment on the bottom. As with the flip design, the
labs at the end of the arm would be designed to rotate, meaning they could be
used at any angle. That would give the hinge ship more versatility then the
flipper: the arm could be lowered to any depth down to 200 metres.
Economically, the arm also has the edge. While the flip ship would have to be
built from scratch, the arm could be added to a converted oil tanker. Thanks to
new regulations requiring the phasing out of single-hulled tankers in favour of
stronger double-hulled ships, second-hand tankers are two a penny. Ness thinks
one could be purchased and converted for around $60 million.
Details remain sketchy, but Ness envisages a lift running up and down the arm
to ferry people and equipment to the labs. Extending the arm would take several
hours, but the design allows for a 10-minute emergency retraction. The arm would
also act as a massive keel, giving the ship tremendous stability. This, of
course, would put enormous strain on the hinge. Ness says he’s solved the
problem but his tricks are under wraps until he can file a patent.
“The OASIS concept, I think, is brilliant,” says Jay Bolton, an independent
marine consultant. “Any of the designs could be done.” Thomas Cummings, a
retired lieutenant commander in the US Coast Guard who designed ships for NATO
forces, agrees. “If we can land on the Moon, we can do this.”
The Ocean Technology Foundation still has some way to go before it has enough
money to build a ship. It’s prepared to rope in anyone with an interest in the
deep sea, from the oil and gas industry to the Navy. But the overall aim is to
open up a new era of ocean exploration. Bizarre they may be, but ships that flip
or have giant hinged arms might just be the breakthrough oceanography has been
waiting for.