New lamps for old: modern nautical terms for ancient marine practices and the navigation of the Zheng He voyages
P.J. Rivers, a retired naval officer and maritime historian, published this article in 2012 in the Journal of the Malaysian Branch of the Royal Asiatic Society to correct widespread anachronisms in the nautical vocabulary used to describe early fifteenth-century navigation, particularly in accounts of Zheng He’s voyages. His central thesis is that the application of modern terms such as “fixing a position,” “latitude,” and “compass-bearing” to ancient practices has created a false impression of advanced navigational capability that did not exist in the 1420s.
Summary
Rivers undertakes a systematic critique of how modern nautical terminology has been misapplied to describe the navigation of Zheng He’s fleets and their contemporaries. He targets both popular works—most notably Gavin Menzies’ 1421: The Year China Discovered the World—and reputable academic sources, including J. V. Mills and G. R. Tibbetts, arguing that even leading specialists have inadvertently imported anachronistic concepts. The article dissects specific terms: “navigation” in its modern sense of exact position-finding did not exist; “latitude” was unknown to ancient mariners who instead measured stellar “heights” (altura or qiyas); “compass-bearing” conflates the direction of an object with the direction a ship is heading; and the so-called “star charts” associated with Zheng He were not navigational instruments but “sailors’ star guides” for recognizing asterisms pointed out by Arab navigators.
The article also corrects a persistent misunderstanding of monsoon mechanics in the Indian Ocean. Rivers demonstrates, using the dated records of the 1431 expedition, that the southwest monsoon does not travel diagonally from the African coast to India and then to Sumatra, but advances as a broad front due north from the equator, breaking first at Aceh in late April, then at Sri Lanka in mid-May, and finally at the Indian west coast in early June. This means the Chinese fleet could sail both eastward and westward across the Indian Ocean during the same northeast monsoon season, a fact that contradicts the commonly stated assumption that monsoon directions simply reverse between the South China Sea and the Indian Ocean.
Rivers further clarifies the nature of the Mao K’un maps, arguing they were not “navigation charts” but “illustrated sailing directions”—coastal drawings with textual instructions that functioned as a pilotage aid, comparable to the modern British Hydrographic Office “Pilots.” He emphasizes that open-sea navigation in this period was essentially “by guess and by God,” with mariners setting off in a general direction on the best course for speed and safety, then making a “good landfall” when they arrived near their expected destination. The primitive magnetic compass—a needle floating in a bowl of water—served only for orientation when the sky was overcast, not for steering precise courses.
Key Findings
- The 1431 expedition records show the fleet sailed from the east to Malacca during the southwest monsoon, then from Malacca to Hormuz on the northeast monsoon, and returned from Hormuz to the Malacca Strait also on the northeast monsoon—proving that both eastbound and westbound traffic could occur in the same season (pp. 87–88).
- The southwest monsoon breaks at Aceh in late April/early May, at Sri Lanka in the second half of May, and at the Indian west coast at the end of May, with Hormuz reached last in early June; the front advances due north from the equator rather than diagonally (pp. 87, 95–96).
- Polaris in the Ming period had an offset of approximately 3.5° from the celestial pole, meaning its observed altitude could vary by as much as 7° between upper and lower transit, making it an unreliable single-star fix (p. 92).
- The Chinese “star plates” (up to eight or twelve rectangular tablets) evolved from the Arab kamal and measured stellar heights in “fingers” (chih = 1° 36′), limited to stars within roughly 20 degrees of the horizon (p. 92).
- The Mao K’un maps, found in the Wu-pei chih (published by 1628), are a series of coastal drawings with texts of no standard size or orientation, with routes running parallel to irregular coastlines “irrespective of true direction”—functioning as illustrated sailing directions rather than navigational charts (pp. 89–90).
- The Chinese marine compass of Zheng He’s era consisted of a magnetized needle floating in water on a wooden plate carved with the Heavenly Stems and Earthly Branches; it had no pivoted needle or graduated card, and was used for orientation in overcast conditions rather than for steering courses (pp. 93–94).
Conclusion
Rivers concludes that the Chinese were foremost in shipbuilding but not in navigational aids, with the sole exception of the Mao K’un sailing directions. The lack of sophisticated instruments—no sextant, no chronometer, no mathematical navigation, no true position-fixing—makes Zheng He’s repeated voyages along the entire length of the Maritime Silk Road all the more remarkable as feats of organizational and logistical management rather than navigational science. He calls for a reappraisal of the so-called “star charts” and suggests the Mao K’un maps may have been an unrecognized inspiration for Western coastal cartography.
Context
- The article draws on primary sources including Ma Huan’s Ying-yai sheng-lan (Mills translation, 1997), the Mao K’un maps from the Wu-pei chih, and the travel records of the 1431 expedition, alongside secondary works by J. V. Mills, G. R. Tibbetts, E. G. R. Taylor, and Joseph Needham.
- Historiographically, the piece contributes to the ongoing correction of the “Zheng He myth” popularized by Menzies, while simultaneously tempering the sometimes overconfident claims of sinologists about Chinese navigational sophistication. It occupies a middle ground between popular sensationalism and academic overstatement, grounded in practical seamanship knowledge.