New Techniques of Archaeology and Greek Shipwrecks of the Sixth and Fifth Centuries BC1
Bass, George F., Proceedings of the American Philosophical Society
WHEN I FIRST spoke to the Society more than forty years ago, the simple fact that I had used diving equipment to excavate a Late Bronze Age shipwreck off the coast of Turkey2 was enough to justify the talk as part of a symposium titled, like this one, "Archaeology: New Techniques and Methods." Now, however, the use of scuba equipment to reach underwater sites is as routine as the use of motor vehicles to reach terrestrial sites.3 Between 1984 and 1994, for example, our Institute of Nautical Archaeology (INA) at Texas A&M University conducted 22,500 dives to depths between 145 and 200 feet4 in order to excavate another Late Bronze Age wreck off the Turkish coast.5 Thus, a paper about diving equipment, suction pipes, and lifting balloons at this symposium would be no more appropriate than a paper about a new model of pickup truck.
Of course there have been improvements in diving equipment since my first underwater excavation, in 1960, which was partly funded and later published by this society.6 Underwater gauges that enable the diver to see the amount of air left in a tank, and inflatable buoyancy compensators, make diving safer, as does the air-filled plastic dome we place on every site as a refuge for any diver with equipment failure.7 In order to avoid decompression sickness, or the bends, we now routinely decompress on pure oxygen, using special decompression tables designed specifically for our work.8 None of this, however, revolutionized our field. Yet other recent technical advances truly have.
I should emphasize that I refer only to technical advances for scuba-diving archaeologists. Oceanographer Willard Bascom, after studying Lloyd's of London records, could write, "Statistics for the eighteenth and nineteenth centuries indicate that approximately 40 percent of all wooden sailing ships ended their careers by running onto reefs, rocks, or beaches made of rock, sand, or coral."9 The same surely held true in antiquity, which means that nearly half of the ships launched in antiquity sank because they struck land. Thus there is sufficient archaeology to be done in relatively shallow coastal water that does not demand the expense of locating and excavating wrecks of similar types and dates far deeper than divers are able to work. Archaeologists could find and excavate numerous Phoenician wrecks less than 200 feet deep for the cost of excavating with robotic tools just one such wreck 1,000 or more feet deep farther offshore, thereby learning more of the past. Nevertheless, I eagerly await the results of work planned by Robert Ballard, Lawrence Stager, and their colleagues on two such very deep Phoenician wrecks.10
What technical advances have been most needed by diving archaeologists over the past four decades? Mainly we strove to increase the amount of work accomplished on a site during a campaign, for our excavators are limited by physiological constraints to only two dives a day of twenty minutes each when working at, say, 145 feet. We once increased those minutes to hours at a time by using saturation diving on a wreck nearly 200 feet deep off the Italian island of Lipari, but we could afford it only because an Italian firm provided the ship, mixed breathing gases, both underwater and surface chambers, a diving bell, a small submersible, and professional divers as part of an exercise to train those divers to work in deep oil fields around the world.11 This was not a practical solution since most of our excavators are normally graduate students who have studied the history and theory of wooden ship construction, and can identify each tiny fragment of wood they uncover. I would not send such students to great depths on mixed gases (although on a Byzantine wreck about 100 feet deep even our students learned to use a special air mixture called nitrox, in which the level of nitrogen, which causes a narcotic effect under pressure, is reduced to less than its normal 80 percent).12
A flexible one-atmosphere diving suit being developed by Phil Nuytten of Nuytco Research Ltd. …