PolyToday: Visiting parent sails through world history

Recently sophomores read about the Age of Exploration in Perspectives on World History. Poly parent Chris Halsted (LA Maritime Institute) took them several fathoms deeper as he explained the growth of sailing knowledge and tools that provided Europeans with the means and understanding to "go global." He demonstrated the usages of astrolabes, azimuth hooks (Marshall Islands), an amal, compasses, and many other navigational developments in the 15th to 17th centuries. While the students were able to handle and experiment with the various navigational tools, they were also mesmerized by several amazing global maps (portolani) from the 15th century, including the incomprehensible Geographica by Ptolemy. Halsted reviewed a quick history of navigation, explained how the Arabs and Chinese had previously impacted sailing, also discussed the various ships (the Arabs' dhow, plus the cog, caravel and carrack), how wind roses and compasses were depicted on maps, and emphasized how trigonometry was crucial to the great naval explorers' ventures. One of the great stories Halsted relayed was how Geoffrey Chaucer became intrigued by an astrolabe: He eventually taught Blanche of Lancaster how to use the astrolabe. She, in turn, taught her grandson, Prince Henry of Portugal (eventually known as Prince Henry the Navigator), who later revolutionized European sailing. Halsted's knowledge and enthusiasm enabled the students to recognize the amazing sailing feats of the "knights of the sea."