The last navigator

Do you really prefer hitech modern satellite navigational gadgets to the romance of the stars and traditional methods, asks a friend? Actually, I think the question raises another: is there really a low tech traditional method in our modern sense of it? For most people, tradition means compass, sextant and chart.

A Micronesian sailing canoe, from The Last Navigator

As I mentioned in an earlier post, I have been catching up with a second hand copy of The Last Navigator by Stephen D Thomas, printed in 1987, which explains exactly how Polynesian navigators have been achieving remarkable feats of accuracy for thousands of years before even the compass was invented, let alone the sextant. The book has underlined for me how hi-tech our “traditional” methods of navigation really are.

A diagram of a sailing canoe from The Last Navigator

For the last 250 years navigators have in reality relied on precision instruments and almanacs full of mathematical calculations of great sophistication. These are methods, materials and advanced technologies that would have astonished the ancients.

A maritime chronomoter, key to longitude measurement, was a major technological achievement of the 18th century, while in its day the modern sextant was a leap forward in precision engineering. It simply was not possible before the 18th century to make instruments of such accuracy.

A great deal of learning and practice went into using both chronometer and sextant, in combination with the immense data resources published in nautical almanacs and the even bigger resource of worldwide nautical charts created by meticulous surveying.

Actually, you don’t even need to learn where all the stars and constellations are to use a sextant. The tables tell you where to look, using your compass and sextant and a rough approximation of how far you have gone since your previous position fix. That surprised me when I learnt how to use mine (a late starter because it was only 20 years ago). There is satisfaction in being able to find and recognise the constellations and the main stars from memory, but it is not at all essential.

Contrast all that with the methods of Polynesian navigators. They are well known to have had no instruments and charts, and to have relied entirely on reading the stars and waves and watching for birds and sea creatures. An aura of mysticism and magic surrounds those achievements. But The Last Navigator brings out the detail of how they actually did it, and it reads as an astonishing feat of memory and long practice, which in its underlying method turns out to connect directly with what we do nowadays.

They used the rising and setting positions of many different stars as their compass; they read information about currents and directions in subtle changes in wave patterns and the surface ripples of water; and bird and sea creature behaviour gave them information about distances from land.

In their heads, they carried the equivalent of a chart of Pacific islands. They fixed their position on it by seeing, in their minds, where lines from the rising and setting points of stars on the horizon intersected, using a reference island chosen for the particular passage they were on.

It was the use of position lines that I found most intriguing. Far from being some unknowable ancient and mystic puzzle, Polynesian navigation essentially did what we do now. Underneath everything was a geometry common to all methods of position fixing. Finding the intersection point of lines from stars and other known objects is the basis of every type of navigational position finding.

Intersecting lines are used by the computer in your GNSS receiver to calculate a position using signals from satellites. “Traditional” navigation using a sextant and chart uses lines measured from precise instrument readings of angles in the sky. For thousands of years Polynesian navigators have achieved a similar feat using no aids at all but memory, observation and experience.

If you want truly to learn to navigate with the romance of the stars and a deep understanding and feel for the natural world, you will have a long way to go. According to Wikipedia, by 2014 these skills were still taught only in the outlying Polynesian island of Taumako in the Solomons.

A new edition of The Last Navigator is still available in paperback, though search now under Steve Thomas, not Stephen D. The charm of the book is that it combines the story of a young man’s ocean adventuring with his quest to be taught the old arts before they disappear.

I also found on Amazon what looks like a much more detailed manual of techniques: We the Navigators: Ancient Art of Landfinding in the Pacific by David Lewis. If I could find a copy for less than £30 I would buy it! There are several blogs for enthusiasts of Polynesian and Micronesian navigation and quite a few replicas have been built to sail.