GEMMA SMITH is grinning like a child on
Christmas morning. “It could be anything!” she says as our boat speeds past the
rugged grey cliffs of Antikythera, a tiny Greek island midway between the
Peloponnese and Crete. We are here to explore one of the world’s most famous
shipwrecks, where divers once found an ancient computer.
The day before, the team discovered part of a
large object buried beneath a metre of sand; now they are back to find out what
it is. After years of preparation, there’s a feeling that today is going to be
big.
The ship that sank here was a hefty wooden vessel,
sailing west from Asia Minor towards Rome when it smashed against the island’s
cliffs in the 1st century BC. It was discovered in 1900 by sponge divers, who
salvaged the site under the direction of Greek archaeologists: the first
scientific investigation of a shipwreck. They found bronze and marble statues,
gold jewellery, ornate furniture, and gorgeous ceramics and glassware. Most
intriguing was an ancient geared device – the Antikythera mechanism. Now
understood to have been a clockwork computer, it was used to predict and
display the movements of the sun, moon and planets in the sky (see “The solar
system in a box“). “It is a symbolic place,” says Theotokis Theodoulou, an
archaeologist at Greece’s Ephorate of Underwater Antiquities. “This is the cradle
of underwater archaeology.”
In 1976, a scuba team led by marine explorer
Jacques Cousteau excavated a small area of the site and brought up hundreds of
small items including jewellery, statuettes and coins, suggesting that much of
the ship’s cargo still lies buried under the sand.
Now, an international team has come to finish
the job. They hope to uncover more exquisite statues, or even other examples of
advanced technology. It is possible that the ship contained several geared
devices, particularly if it was carrying a commercial consignment rather than
stolen loot, speculates Michael Wright, a London-based mechanic and curator. “I
live in hope!” he says.
The project is led by Theodoulou, his colleague
Dimitris Kourkoumelis at the Ephorate of Underwater Antiquities and Brendan
Foley, an archaeologist at Woods Hole Oceanographic Institution in
Massachusetts. The $1.8 million scheme, funded largely by private and corporate
sponsors, is one of biggest underwater archaeology efforts in world, and dwarfs
those carried out before in Greece.
There are two main challenges. Few
archaeologists are qualified to dive to the site’s 55 metres, where the risk of
the bends is severe. So to avoid injury, they descend with dive specialists
including Smith, and only dive for 45 minutes at a time, taking 90 minutes to
decompress.
Another problem is finding items hidden in the
sand. Cousteau’s 1976 team used a huge suction pipe to hoover up the seabed,
dumping sediment and precious artefacts onto the deck of their ship. But the
priority now is to record and understand the site, not simply to salvage its
treasure.
So in June, Foley and a team from the
University of Sydney in Australia used stereoscopic cameras and sonar mounted
on an underwater drone to make a 3D map of the site (see
diagram).FIG-mg30404201.jpg
Reconstruction site
Then, at the end of August, the dive team
arrived on this windswept island. Its members surveyed the site with handheld
metal detectors, investigating hits by fanning water with their hands to dig
shallow trenches, and sucking away the raised sediment with a small dredge.
They marked any finds directly onto the 3D map as they worked, using an iPad in
a waterproof case.
While underwater, the researchers also took
hundreds of photographs from different angles of artefacts and of an excavation
trench. Software then crunched these into a 3D virtual reconstruction.
Such software is changing the way underwater
archaeology is done, says team member Brett Seymour, an underwater photographer
for the US National Park Service. It allows researchers to map sites quickly
and accurately instead of spending days with tape measures and drawing objects
by hand.
“This site is inherently remote and difficult
to access,” adds Foley. “But through virtual reality and 3D modelling we can
make it accessible for any archaeologist anywhere in the world.”
The first couple of weeks of the diving
expedition yielded a slow stream of finds including ship components such as
roof tiles and lead hull sheeting as well as finer items: sections of a bone
flute, a blue game pawn and a statuette base. “These are prestige goods,” says
Foley, “not the sort of thing you normally find on a wreck.”
Everyone was hoping for a headline-grabbing
find, however, and on 8 September a shoebox-sized block of black metal,
weighing nearly 30 kilograms, caused excitement. It was immediately dubbed the
ship’s “black box”. But the metal turned out to be iron, probably a ballast
weight dropped by Cousteau’s diving saucer.
A couple of days later, diver Alexandros
Sotiriou uncovered the square end of a large object buried deep in the sand. He
was unable to move it, but believed he saw the green glint of semi-precious
bronze.
Now, as the team reaches the wreck site to
investigate Sotiriou’s find, the excitement is palpable. As the first two
divers descend, their colleagues and I crowd round a small screen on the boat,
which shows a live video feed of progress underwater.
The divers wedge their scooter against a rock
and use its propeller to create a water jet that pushes sand away. The pair
disappear into a cloud of sediment, and later emerge with two long bars, each
with a semicircular hole halfway down its length. The bars turn out to be lead,
not bronze; the components of a large anchor. The team is quiet on the way back
to harbour – this isn’t what the divers had hoped for. But it’s still a
significant find, showing how deep the team must dig for larger items, and
pinpointing the position of the ship’s bow. With the stern already located,
Foley and Theodoulou calculate the vessel’s midpoint – a flat, featureless area
dubbed “the meadow” – as the most likely place for its cargo.
The next day, Smith and Foley dig two
70-centimetre-deep trenches in the meadow. They surface jubilant. Within half
an hour, they have uncovered several items, including a part of an amphora and
an elegant wine jug. Smith’s pockets are filled with small bronze pieces –
nails, and what might be parts of a cooking pot. “There’s obviously stuff down
there,” she says. “We just weren’t digging deep enough before.” It’s the best
dive of the project and Foley is convinced the team is about to reach the
ship’s cargo. “That’s the way to go,” he says. “Now it’s just a matter of
time.”
But at this treacherous site, the project is at
the mercy of the elements. The unrelenting north wind makes it too dangerous to
dive again, and the divers pack for home, where they will collaborate with
other teams to run tests on the recovered artefacts. Lead isotope analysis
could reveal the ship’s geographic origin, and DNA analysis could shed light on
the make-up of ancient products.
But to discover if the wreck hides the
treasures they dream of, perhaps even another ancient computer, they must wait
for next year’s expedition.
This article appeared in print under the
headline “Diving for pearls of Greek wisdom”
By Jo Marchant
