On top of this, the model also required geographical information on the location of 994 islands and coasts and a variety of factors affecting survival at sea. These last were combined into a “risk probability table,” compiled with the help of the Naval Life Saving Committee of Bath, which took into account “the fact that some vessels will carry provisions, water, or fishing equipment, and that some will have luck and others none.” The table suggested that the probability of dying increased substantially after about seven weeks at sea, and that by week 25 the chances of survival were effectively nil. Risks to the vessel itself—of swamping or breaking up—were envisioned as a function of wind; the model assumed that a wind of Force 9 or greater gave the vessel “a 50 percent chance of surviving to the next day.”
The process of transcribing nearly 800,000 separate entries on winds and currents, keypunching, assembling onto magnetic tape, and checking was a “mammoth task,” and it was not until 1967 (three years from conception) that the researchers were finally ready to run their first computations. The volume of data was also too great for the computer they were using—a Ferranti Atlas that occupied two floors of a house owned by the University of London—to store in its main memory. Considered the fastest computer in the United Kingdom at the time, the Atlas was so much in demand that Levison had to run his program in the middle of the night. “Once a week for several weeks,” he writes, “I had to leave my London suburban home at 3.00 a.m., drive 45 minutes into Central London, run the program, and arrive home around 5.30.” But the results, when they finally came in, were worth the trouble.
Out of more than 120,000 simulated voyages, begun at points all over the Pacific and conducted at all times of the year, some highly likely drift routes did emerge. These included Tonga to Fiji, Pitcairn to the Tuamotus, the Marquesas to the Tokelaus, and several others, all of which entailed travel from east to west. Almost no drifts going the other way, from west to east, emerged from the experiment. The results gave “no support” to the possibility of drifting along what was then envisioned as a likely Polynesian pathway from Samoa to the Marquesas, while the chance of drifting from Samoa to the Society Islands was less than one in seven hundred.
Then there were the islands to which it was impossible to drift no matter where you started. One of these was Hawai‘i. Out of sixteen thousand drift experiments begun at points all along the northern boundary of central and eastern Polynesia, with extra experiments starting in the Line Islands and the Marquesas, not one ever reached the Hawaiian Islands. In fact, almost no voyages begun in central and eastern Polynesia ever managed to get north of the equator; even those begun on Christmas Island (around 2 degrees north latitude) never got farther than about 10 degrees north.
Nor would a drifting canoe ever be likely to reach New Zealand. None of the many thousands of drift voyages begun on the southern margin of tropical Polynesia—the presumed starting point of New Zealand’s first settlers—ever reached Aotearoa. This was a surprise to the New Zealander Ward, who had seen the trunks of coconut palms washed up on a beach at Opotiki, in the Bay of Plenty. But the only drift path from the tropics that led to New Zealand in the simulation came from the Kermadecs, a string of tiny, uninhabited islands halfway between New Zealand and Tonga.
As for Easter Island, the third point of the Polynesian Triangle and one of the most isolated islands in the world, the chance of drifting there from anywhere in Polynesia was next to zero. It was also “virtually nil” from the coast of South America: with a single exception, every one of the more than four thousand drift voyages begun on the coast of Peru landed farther north on the South America coast or in the Galápagos or were lost at sea. This would seem to contradict Heyerdahl’s experience in the Kon-Tiki, but it’s important to recall that Heyerdahl’s raft had been towed well out to sea before the start of his epic journey. The computer simulations confirmed just how necessary this had been; in the experiment, the only voyages from South America that succeeded in making landfall in Polynesia were begun 450 miles off the Chilean coast.
The authors of this study acknowledged that the whole problem of Polynesian voyaging might well be one that, by its very nature, “defies proof.” But their results were still compelling. Based on the computer simulation, the chance of settling Polynesia by drift voyaging alone looked infinitesimally small. Even Sharp, however, had allowed that it was not purely a matter of drift: some human decision-making had to be taken into account. To address this, Ward, Webb, and Levison devised a variation of the main experiment, which they referred to as “voyaging with intent.” In these experiments, they added the capacity to steer as close as possible to a specified direction, allowing the vessels to hold a course of 90 degrees or greater to the wind.
Under these conditions, it proved quite probable that a canoe starting in Samoa and traveling east would reach the islands of eastern Polynesia—Tahiti, the Marquesas, the Tuamotus, the southern Line Islands, and the Northern Cooks—and a handful even went on to the coasts of Panama and Colombia. It was also possible (an 8.5 percent chance) for a canoe traveling north-northwest from the Marquesas to reach Hawai‘i, while a canoe traveling southwest from Rarotonga would reach New Zealand more than half the time. Thus, the researchers concluded, while the settlement of Polynesian by drift alone was a nonstarter, there were “good chances of successfully crossing all the major ocean stretches within and around the Polynesian Triangle, with a very limited degree of navigational skill, within a reasonable survival period, and in craft which have poor capability of sailing to windward.” As a standard for Polynesian voyaging, it was a pretty low bar, but it did appear to settle the question of whether some degree of seamanship and navigation had been necessary to reach the islands of Polynesia, and, as an example of cool, quantitative reasoning, it was difficult to refute.
The Non-Armchair Approach
David Lewis Experiments
Polynesian wind compass, in Myths and Songs from the South Pacific by the Rev. William Wyatt Gill (London, 1876).
HARVARD UNIVERSITY LIBRARY.
IT WAS ONE thing to assert that “some navigational ability” had been required to settle the islands of Polynesia, and quite another to articulate how it had worked. What actual navigational methods might the original settlers of Polynesia have used? What conceptual tools did they have in their tool kit? How seaworthy, really, were their canoes? The inspired intervention of Ward, Webb, and Levison had brought a breath of fresh air to a debate that had become “stultified by shortage of facts.” But the computer simulation had never been designed to answer the question of how such voyages might have been accomplished. For this, something quite different was needed—perhaps even a return to voyaging itself.
“Most scholars are landlubbers,” wrote one of the people involved in this new phase of the inquiry. And it was quite true that, since the early nineteenth century, almost everyone writing about Polynesian voyaging had been an armchair theorist (with the obvious exception of Thor Heyerdahl). That all changed in the 1960s and ’70s, thanks, in large part, to Sharp’s provocations and to the man who emerged as his archnemesis in the drift debate, a physician and blue-water sailor named David Lewis. Lewis had been born in the United Kingdom but had grown up in New Zealand and lived for a time as a child in the Cook Islands. He described himself as having been interested from a young age in Polynesian seafaring—a subject he associated with memories of “trailing my toes luxuriously through the warm red dust, clad only in a pareu [sarong], and on moonlit nights, surreptitiously watching, with my friends, parties of silent men illegally poisoning lagoon fish with crushed utu fruit, or equally secretly, from the under the palms, watching the hula dancing.”
Following the Second World War, Lewis set up as a doctor in London, but in 1964 he left his practice to sail around the world with his family—including two daughters, aged three and four—in a catamaran called the Rehu Moana (Ocean Spray). A keen yachtsman, he had already made three solo crossings of the Atlantic, but for this particular vo
yage he had a special plan in mind. During their passage across the Pacific, he would test some of the navigational methods attributed to the ancient Polynesians. Lewis believed that attempts to understand indigenous navigation in the Pacific had been “hampered by too theoretical an approach,” and he saw the voyage as an opportunity “to bring academic theories about oceanic navigation down to sea level.”
The plan was to retrace the route believed to have been taken by the first settlers of New Zealand—from the Society Islands via the Cook Islands—without using any instruments, thereby testing the accuracy of “star and sun steering by eye alone.” Lewis was surprised to find that, in spite of his “inexpert performance and secondhand knowledge of the techniques,” the method was surprisingly accurate. At the end of the longest leg of the test segment—a run of seventeen hundred miles from Rarotonga to New Zealand—his landfall was off by less than half a degree of latitude, a mere twenty-six miles. For the next three years, Lewis and his family wandered around in the Rehu Moana, visiting many of the remoter corners of the Pacific, where he was further surprised to discover navigators who still used traditional techniques, eschewing modern tools like maps and compasses.
In 1968, he secured a research fellowship from the Australian National University—“a most unusual fellowship,” as one of his American colleagues enviously described it, “that allowed him to sail about the Pacific in search of islanders who might still know the old ways.” Lewis set out again, this time with his twenty-year-old son in a ketch called the Isbjorn, to track down and sail with some of these navigators. Among those who instructed him was a man named Tevake, from a Polynesian outlier in the Santa Cruz Reef Islands. The “outliers” are a scattering of small islands that lie outside the Polynesian Triangle, in what is officially Melanesia, but are occupied by people who speak Polynesian languages and have Polynesian cultural traits. Once thought to represent a breadcrumb trail left by the original Polynesian migrations, they are now understood to be communities of later settlers who traveled—or possibly were swept—back westward from Polynesian homelands like Samoa. The outliers, incidentally, are one of the few categories of Polynesian islands to which, according to Ward, Webb, and Levison’s computer simulation, it is actually quite easy to drift.
Tevake, wrote Lewis, was “an old and wrinkled man by the time I knew him . . . the first Polynesian navigator I ever sailed with, and one of the greatest.” In his prime, he had made journeys of up to 320 miles, as far as Tikopia and Vanuatu. His thirty-foot outrigger canoe had long since been wrecked, but, “old as he was, . . . he still ranged ceaselessly among the islands.” Lewis and his son also traveled to Micronesia, where they sailed with a navigator named Hipour from the atoll of Puluwat, in the Caroline Islands, and took instruction from Iotiebata and others in the Gilberts. Over time, Lewis sought out information (it was “hardly appropriate,” he wrote, to describe the men he spoke with as “informants,” when they were explicitly master teachers and he explicitly their pupil) in the islands of western Polynesia, Micronesia, Melanesia, Indonesia, even Alaska and the Russian Far East.
The upshot of it all was the realization that the ancient sea lore of Oceania had not been lost, as so many believed, but could still be found scattered among the islands as “a mosaic of fragments . . . only waiting to be put together.” The second important realization was that traditional navigational techniques and concepts were remarkably consistent across a huge swath of the Pacific. All the evidence pointed to a single navigational methodology, a “former Pacific-wide system,” albeit with local variations. This came as a surprise to Lewis, who had been cautious about assuming that techniques still in use on remote atolls in Micronesia might be the same as those employed in other parts of the Pacific. They all, however, appeared to incorporate a set of key elements that included detailed lists of stars and star paths; sophisticated orientation concepts; and a wide array of landfinding techniques, some of which could be readily translated into Western conceptual terms, but others of which reflected ways of seeing and thinking with no obvious corollary in the European tradition.
Lewis, whose training and cultural background had ingrained in him an attitude of intellectual caution, was persuaded. Based on his own experience and the testimony of those he met, he became convinced that the islanders of the Pacific had had the vessels, the knowledge, and the techniques to traverse the great expanses of the Pacific, to make landfall on islands that were known to them, and to find their way home from those that were not.
LEWIS’S CONCLUSIONS WERE not so terribly different from those that had been reached by others along the way, but the pathway to them was entirely new. He had tested the navigators’ methods by putting his own sailboat into their hands and watching them navigate, using nothing but what they could feel and see and the information they held in their minds. He describes how these wayfinders, as they are often called, kept course using the rising or setting points of a succession of stars, which constituted the “star path” from one island to another. About ten stars a night were required to maintain a constant heading, though sometimes as few as five could be used. Even when the heavens were obscured by cloud, he noted, the most experienced wayfinders knew the sky so well that the appearance of just one or two stars was enough to orient them.
On his first night of sailing with Hipour, Lewis observed how he steered first toward the setting Pleiades, then, as they became masked by clouds, how he kept the rising Great Bear to one side, in line with part of the rigging, then held the Pole Star in line with the edge of the wheelhouse, while keeping “the sinking Pollux fine on the starboard bow.” At one point, Lewis wrote, “a strange star appeared at which I stared in surprise; but Hipour merely grinned and remarked, unexpectedly in English, ‘Satellite.’”
Star lore is the foundation of non-instrumental navigation, but stars, as Sharp had pointed out, are visible only at night, and so another method was required for navigation by day. Navigators could steer by the sun for a few hours at the beginning and end of the day (otherwise it was too high in the sky) and at noon (when the shadow of the mast will give north and south). But they also used another very important—and, to Westerners, much less familiar—technique: that of reading the ocean swells. Swells are not the same as waves. Waves are a local phenomenon thrown up by winds in the immediate vicinity; swells, by contrast, are waves that originate far away and travel beyond the winds that generate them. The important swells, those created by enduring weather patterns like the trade winds or the westerlies in the South Pacific Ocean, tend to have long wavelengths and to move past the boat “with a slow, swelling undulation.” This does not necessarily mean they are easy to recognize, for in practice the actual pattern of waves and swells at any particular point will be a complicated mix of “systems that differ in height, length, shape, and speed moving across each other from different directions.”
Despite having sailed for years on the world’s great oceans, Lewis reported that he could not consistently differentiate the various patterns of waves and swells and would frequently have to have them pointed out. On a passages with Tevake, the navigator showed him how the “Long Swell,” from the southeast, and the “Sea Swell,” from the east-northeast, passed “through each other like the interlocked fingers of two hands.” It was not so much a matter of seeing them as of feeling the changes in the movement of the vessel: which part of it meets the wave first, how it rocks or rolls or corkscrews as it’s lifted up and then falls. Sometimes, Tevake told him, he would lie down on the outrigger platform, the more clearly to feel the pitch and roll of his canoe and thus disentangle the different forces. Lewis also reported a bit of wisdom related to him by a “veteran island skipper,” who had been told that “the most sensitive balance was a man’s testicles.”
In addition to sun, stars, and swells, wayfinders used winds to steer, though this was the least accurate, given the frequency of wind shifts on the open ocean. (Lewis reported that on his passage from Rarotonga to New Zealand, there were n
o fewer than sixty-four changes in the direction of the wind.) Wind compasses are one of the very few bits of navigational lore to have survived in eastern Polynesia, where they were recorded on several islands in the early nineteenth century. These were not physical objects or drawings—though pictures were made of them by European missionaries—but conceptual systems that were visualized, in at least one group of islands, as a series of holes at the edge of the horizon, “some large and some small, through which Raka, the god of winds, and his children love to blow.”
SO FAR, NONE of this is terribly hard for a Westerner to comprehend, even if he cannot replicate the skills represented. But there is one component of the navigational system described by Lewis that is quite alien to European thinking. It is attested in only one place—the Caroline Islands, where it was first described by the anthropologists William Alkire and Thomas Gladwin in the early 1970s—and may never have existed in precisely this form anywhere else. Nevertheless, it is a salutary reminder of how much more there is in heaven and earth than is dreamt of in our philosophy.
In order to keep track of their progress on a long voyage out of sight of land, Carolinian navigators use a system known as etak, in which they visualize a “reference island”—which is usually a real island but may also be imaginary—off to one side of the path they are following, about midway between their starting point and their destination. As the journey progresses, this island “moves” under each of the stars in the star path, while the canoe in which the voyagers are traveling stays still. Of course, the navigators know that it is the canoe and not the islands that are moving, but this is the way they conceptualize the voyage. They organize all the information they need—the distance to be covered, the speed at which they are traveling, the bearing of each star relative to the canoe at each stage of the journey and to the islands at either end—into a mental map made up of etaks, or segments, each of which is completed as the reference island passes under each star in the star path in turn.
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