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Volume 15, Number 6November/December 1964

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Diggings In The Deep

Down to the bottom of the Mediterranean go the divers in search of knowledge…

Written by Honor Frost

To the armchair devotee of marine archeology—that fascinating blend of deep-sea diving and rigorous scholarship—it must seem that the youthful science has belied its initial rich promise, for no new Pompeii, Troy or Jericho has been uncovered or even hinted at from the depths of the sea. Thrilling reports of submarine discoveries, on sober scientific examination, turn out to be but small pieces in the mosaic of submerged history which as yet reveals no definite pattern. Considering the avid curiosity surrounding each new attempt to wrest its secrets from the sea the results have, indeed, proved disappointingly meager. Yet it would be a mistake to assume that, because accounts of pioneer research are inconclusive, controlled techniques of underwater excavation are not being developed: though barely out of its teens, marine archeology looks confidently toward the day it will be possible to reconstruct ancient ships from keel to masthead from fragmentary sunken remains.

Free diving has come a long way since Jacques Yves Cousteau and Emil Gagnan in 1943 invented the aqualung, which in turn gave birth to marine archeology. In the early days, news of now-famous archeological discoveries was rushed into print, before their significance could be measured. In those days too, not only was comparative knowledge lacking, but also a professional approach to the problem of undersea excavation. Sometimes divers of undoubted skill and experience were forced, by lack of time and money, either to hurry their work or abandon it in its early stages. Others tried to excavate wrecks, buried under tons of sand and silt, with their bare hands, hopefully recording their discoveries with a camera in a leaky case. This is no longer the way it is, but even when funds permit the use of heavy-duty digging and lifting machinery, television cameras and adequate boats and crews, trouble dogs the divers because the proper utilization of the equipment requires training seldom found among divers interested in archeology and because marine archeologists simply haven't developed the techniques appropriate to their needs as have dry-land archeologists. No way, for example, has been found to entirely solve the problem of time.

On land, it is conceivable that an energetic archeologist could excavate a whole village in a year or two, if provided with an adequate number of trained workers to assist him. In contrast, it may take years merely to raise the cargo from the wreck of a single ancient sailing ship, leaving aside the all-important task of recording the positional relationships between the objects raised. For underwater, both the number of divers that can work on a single site, and the time they may remain submerged, is severely limited.

The excavation of a Roman ship that sank off Grand Congloue island near Marseilles, France, illustrates the frustrations of the underwater archeologist fighting the clock. This was the first ancient wreck to be salvaged by free divers only, i.e., divers breathing from compressed-air tanks strapped to their backs instead of receiving air from the surface through hoses. The campaign lasted eight years, yet at the end of that time a good deal of the cargo and hull remained fast on the bottom. Captain Cousteau's team of divers had worked constantly, but because the wreck lay at a depth of nearly 150 feet, no diver could spend more than a total of half an hour a day under the pressures found at the bottom. His first dive lasted about 20 minutes; then he had to wait at least six hours before making his second and final dive of the day, lasting a mere 10 minutes.

Depth curtails diving time because of the dangerous side effects that occur when air is breathed under pressure. The most serious is the "bends," severe (and sometimes fatal) body cramps caused by the sudden release of nitrogen bubbles, absorbed by the diver when receiving air under pressure, from his blood stream as he rapidly ascends to the surface. The maximum time a man can safely spend at any given depth has been computed and published in tabular form. If the stipulated period is exceeded, he must undergo stage decompression. That is, on the way to the surface, he must stop at certain levels for minutes, or even hours, while the nitrogen slowly and painlessly passes from the blood stream to the lungs and is expired. Diving day after day is more hazardous still, for it demands cumulative decompression, the neglect of which may cost the diver his life or lead to incurable paralysis. Ironically, divers can spend the least time at sites where they want to spend the most, for well-preserved wrecks are found only in deep water, where they are beyond the ravages of wind and current.

Dry-land archeology is a science with well-developed techniques more than a century in the making, but marine archeology is very much in the experimental stage. And while ordinary archeological expeditions are assuredly complicated ventures, underwater investigations are burdened by the necessity of having to be full-blown diving expeditions involving much more specialized and hazardous equipment, trained diver-archeologists, of whom there are few, and teamwork that assures safety as well as scientific efficiency. They also demand speed and continuity of effort, both dependent on not merely good but excellent weather conditions on the surface. That optimum conditions are rarely met is depressingly evident from the fact that so far no ancient ship, complete with cargo, has been fully excavated.

In underwater archeology there is another vital problem that has, until recently, gone unrecognized: the need for comparative knowledge of underwater sites. Without such knowledge, it is impossible to understand the significance of submerged remains. Many good divers do not even recognize an ancient wreck when they see one, for a few fragments of pottery may be the only indication that beneath a low mound of sand lies the remains of a ship. Harder yet to identify are off-shore moorings, which are marked only by groups of pierced stones or the lead components of ancient anchors.

These "cemeteries of lost anchors" provide an insight into the methods of the marine archeologist and the way in which he interprets his findings. Their presence near reefs or in off-shore shallows is explained by the inability of ancient sailing vessels to cruise into the wind. When the wind was adverse, they had to anchor and wait for the wind to shift. The rope lines often parted, leaving the anchor on the bottom. Since vessels of about 500 tons carried up to 20 anchors, Mediterranean reefs and shallows are littered with ancient anchors, which range in size from chunks of pierced stone which can be lifted with one hand, to lead-stocked six-footers which require five strong seamen to manhandle aboard.

It is possible to account for the presence of these anchor cemeteries with a fair degree of confidence. Julius Caesar, in The Conquest of Gaul, mentions with surprise the possession of strong anchor chains by an enemy French tribe called the Veneti, and thus confirms other evidence that rope anchor lines were standard equipment on Roman ships at the beginning of the Christian era. (It also indicates that Roman wrecks bearing anchors with chain belong to the period after Julius Caesar.) Rope not only breaks more easily than chain but, having a tangential traction under water, tends to work loose from the attached anchor. From the Biblical description (Acts 27: 28-29) of St. Paul's wreck off the island of Malta, we can calculate that that particular Roman ship carried at least eight anchors.

The places where ancient anchors were lost are eloquent pages of history for those who can learn to read them. Divers will notice that on steep submarine cliffs there will be only lead stocks (in ancient times, when anchors were made of wood, the cross bar or "stock" was often of lead to keep the fluke imbedded in the bottom) and primitive iron anchors. On certain off-shore shallows, stone anchors predominate. If we can discover where each type of anchor was made, and in what period, the analysis of each collection will thus delineate a trade route and even, perhaps, tell us something about the methods of navigation used by the various sea peoples in ancient times.

It is quite easy to date Roman anchors because hundreds of wrecks have been found and some of them have their anchors in place. The construction of Roman ships is well known from written records, so it is possible to pinpoint the dates of their anchors with reasonable accuracy. Stone anchors are as yet less familiar to archeologists, but their study promises even greater rewards. This is because they were considered sacred objects, and in the Bronze Age were placed in temples as votive offerings. The manufacture and function of these anchors, fortunately, is not so deep a mystery as the history of their development, for stone anchors of a very similar design have been used in the Eastern Mediterranean and the Arabian Gulf right up to the present day.

Another type of site familiar to divers, but one which has so far escaped the attentions of marine archeologists, is the bay used as shelter from storms. In antiquity, ships driven into such havens left debris behind them—pottery sherds, broken weapons and tools, and so on—in the same way that modern ships litter harbors today with beer bottles, tin cans and plastic bags, all of which eventually winds up in the silt on the bottom. Successive layers of this debris would, of course, give clues to the relative dates at which the objects were deposited, the more recent being in the uppermost strata. Analysis of stratified deposits has long been a standard method of date-interpretation in dry-land archeology, but, as yet, has not become a useful tool of underwater methodology.

As if to make amends for the violence of the storms which sent ancient wooden ships to the bottom, the submarine environment preserves what is left of them with remarkable fidelity. When a ship settles on a suitably sheltered sandy bottom, it will be metamorphosed through waterlogging, the growth of marine concretions, and sand burial. The latter phenomenon is due to the interruption of the natural flow of sediment, which in consequence piles up around the obstacle until it is buried and the natural equilibrium of the bottom is restored. Assimilation of a wreck may take 50 to 100 years but, once complete, the remains of the ship will be stabilized for millennia. In the process, metal fittings such as iron nails corrode into nothingness, but not before lime secretions of sea animals form around them, making a sturdy mold into which today's technicians can pour plaster to reproduce the original with exactitude.

The excavation of man-made harbor installations of great antiquity depends, in part, on divining the harbor designers' original intentions. Dredging was not invented until the Middle Ages, so the ancient harbors had to be flushed out, either by use of natural currents, or by the creation of artificial currents released through sluice gates, as at the Phoenician port of Sidon. Silt erosion and subsidence have now hidden the greater part of ancient harbor works, and what remains cannot be reconstructed unless archeologists can guess how the original designers intended them to function.

Since excavation entails destruction of a site, for after all a find is necessarily brought to the surface piecemeal, it is vital that meticulous records be kept of every discovery and every mechanical operation involved, so that mistakes can be caught and rectified on future jobs. It is possible, using graphite crayon on sheets of frosted plastic, to sketch underwater artifacts even at depths of 125 feet. Metal pipe-and-wire grids placed over the site give precise points of reference to chart and photograph the site, while underwater compass readings provide geographical orientation. Record-keeping is as unremitting as it is important, for each stage of an excavation must be mapped as the many tons of sand and silt are carefully brushed and blown away to reveal what is below.

For all the problems, however, marine archeology is steadily developing. Little by little, what was once the preserve of eager amateurs is becoming a fledgling science. The crippling limitation of brief periods of working time on the bottom is already being overcome by the use of submarine "houses," which enable divers to remain at the bottom for a week or more, while the worst effects of depth itself are being mitigated by the use of oxy-helium mixtures and other oxygen combinations instead of conventional compressed air. Excavation underwater is today, in a sense, a function of economics rather than technical progress, for while many excellent dry-land techniques can theoretically be applied to yield good results under the sea, their cost is as yet prohibitive.

While this remains true, amateur divers have an important role to perform in underwater research. Too often in the past their number has included souvenir hunters who ripped artifacts out of their context, obliterating scientific and historical data of immense value for the sake of a trinket or two, soon discarded. Anyone can wrench antiquities from the sea, but if they are not to destroy what they say they love, they must first set themselves to the less spectacular tasks of charting, of making a comparative study of marine sites, and of keeping abreast of technical progress by experts in underwater work.

Honor Frost, an Englishwoman, studied art as a vocation, archeology as a hobby and free diving for pleasure. She is the author of Under The Mediterranean, a book derived from her ten years' experience as an underwater archeologist.

This article appeared on pages 28-32 of the November/December 1964 print edition of Saudi Aramco World.


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