Navigation between the islands

The Marshall Islands in eastern Micronesia consist of thirty-four coral atolls consisting of more than one thousand islands and islets spread out across an area of several hundred miles. In order to maintain links between the islands, the Marshall Islanders built seafaring canoes. These vessels were both quick and manoeuvrable. The islanders developed a reputation for navigation between the islands—not a simple matter, since they are all so low that none can be seen from more than a few miles away.
Navigation chart (rebbelib), probably 19th century AD, Marshall Islands, Micronesia, wood, shell, 1 meter wide, © Trustees of the British Museum
Navigation chart (rebbelib), probably 19th century C.E., wood, shell,
67.5 x 99 x 3 cm, Marshall Islands, Micronesia 
© Trustees of the British Museum
In order to determine a system of piloting and navigation the islanders devised charts that marked not only the locations of the islands, but their knowledge of the swell and wave patterns as well. The charts were composed of wooden sticks; the horizontal and vertical sticks act as supports, while diagonal and curved ones represent wave swells. Cowrie or other small shells represent the position of the islands. The information was memorized and the charts would not be carried on voyages.

Rebbelib

This chart (above) is of a type known as a rebbelib, which cover either a large section or all of the Marshall Islands. Other types of chart more commonly show a smaller area. This example represents the two chains of islands which form the Marshall Islands. It was collected by Admiral E.H.M. Davis during the cruise of HMS Royalist from 1890 to 1893.

Mattang

This chart (below) is of the type known as a mattang, specifically made for the purpose of training people selected to be navigators. Such charts depict general information about swell movements around one or more small islands. Trainees were taught by experienced navigators.
Navigation chart (mattang), probably 19th or early 20th century C.E., Marshall Islands, Micronesia, 75.5 cm © Trustees of the British Museum
Navigation chart (mattang), probably 19th or early 20th century C.E., Marshall Islands, Micronesia, 75.5 cm © Trustees of the British Museum
Navigation charts continue to be made, often simpler in form, to be sold as souvenirs.

Suggested readings:
TW. Davenport., "Marshall Islands cartography," The Bulletin of the University Museum of Pennsylvania, 6: 4 (Summer 1964), pp. 10 -13.
J. Feldman and D.H. Rubinstein, The Art of Micronesia (Honolulu, The University of Hawaii Art Gallery, 1988).
A.C. Haddon and J. Hornell, Canoes of Oceania (Honolulu, Bernice P. Bishop Museum Special Publications 27-29, Reprinted as one volume, 1975).
T.A Joyce, "Note on a native chart from the Marshall Islands in the British Museum," Man-1, 8 (1908), no. 81, pp. 146-49.
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