Based on the length of the nautical mile, knots were tied along the log line at intervals of 14.4 meters. “A wedge-shaped piece of wood, a small glass timer, and a really long rope.”īut not just any rope would do. “They used materials they had on hand,” she explains. But when the nautical mile - 1.852 kilometers - was introduced in the 15th century, they had a handy standard against which to measure speed and created out of necessity the chip log, the world’s first maritime speedometer. “With no landmarks to gauge their progress across the open sea, sailors couldn’t tell how fast or how far they were traveling,” explains Camila Caballero, an MIT senior and the academic coordinator for Amphibious Achievement, an athletic and academic outreach program for urban youth in Boston.

Unless sailors knew how fast they were going, they could end up days off schedule, endangering those on board and worrying loved ones awaiting them in port. Because 15th-century sailors didn’t have GPS… By Sarah JensenĪdventure novels and history books are filled with harrowing stories of sailing ships delayed at sea - tales of sailors running low on food and fresh water, dying of scurvy, and getting trapped in the doldrums, or the tropics during storm season.

Boots of blinding speed location