Seabed secrets of an ancient cargo ship

By Louise Murray - Engineering and Technology Magazine
 

A scientific expedition to an ancient Mediterranean shipwreck reveals the luxurious lifestyle of wealthy Romans in the time of Caesar.

This year, marine archaeologists have been exploring the richest ancient Greek shipwreck of all time using 21st-century technology. The vessel, which sank in around 65 BC, was a 65-metre boat packed with luxury goods from the craftsmen of ancient Greece and the eastern Mediterranean, destined for the burgeoning Roman market.

From the evidence of silver coins found on board, it probably began its journey in Pergamum or Ephesus in modern-day western Turkey, stopping off at the tax-free port and trading centre of Delos in Greece to pick up further goods. The ship sank off the coast of the tiny Greek island of Antikythera en route to a Roman port and the main market for its luxurious cargo.

Brendan Foley, a historian, archaeologist and diver from the USA’s Woods Hole Oceanographic Institute (WHOI), leads the expedition. “Every single dive delivers fabulous finds and reveals how the ‘one per cent’ lived in the time of Caesar,” he notes.

The ship carried art masterpieces of the age, destined for Roman villas: exquisite bronze and marble statues, glassware from Syria and Lebanon, ceramics, bronze couches and amphorae and most important of all, the unique Antikythera mechanism.

This was a sophisticated astronomical calculator, dubbed the world’s first analogue computer and the only one of its kind ever discovered. Even after three waves of exploration, much of the cargo remains deep under the water, as yet untouched.

The wreck was first discovered in spring 1900 by sponge divers. A major recovery of its treasures was made later in the year with the help of the Greek Navy, by divers in bronze diving helmets who were supplied with air pumped from the surface.

Jacques-Yves Cousteau visited the site in 1953 on his expedition ship Calypso and returned to lead a major excavation of the wreck in 1976 as part of a film project, using a small submersible.

Yet it was not until 2014 that a major new expedition began working onsite, its first truly scientific excavation. The multi-year expedition is a collaboration between the Greek Ministry of Culture and WHOI.

“We’ve trained our marine archaeologists for five years to be ready to work this wreck,” Foley. “It’s deep, much of it lies at more than 50 metres and for us to be able to spend reasonable working time down there safely we’ve had to learn to use rebreather technology instead of scuba tanks and air.”

The closed-circuit rebreathers chemically scrub the carbon dioxide from the exhaled breath and top up the inhaled breath with oxygen.

To avoid the bends on ascent due to nitrogen accumulation in the body’s tissues, the necessary long decompression stops are made on gas mixes, culminating in the divers breathing pure oxygen near the surface.