Ship's speed

One thing that stood out to me in reading excerpts from Clifford Connor's A People's History of Science: Miners, Midwives, and "Low Mechanicks" was Connor's description of how sailors determined how fast they were traveling. Sailors did this by spitting in the water and timing the rate of the spit moving, which was timed by reciting Hail Mary's. This seemed to be the height of technology at the time, until more advanced techniques were created and/or discovered. This demonstrates how scientific inventions may not always be fast tracked, but that they can sometimes make the way of life easier when they are implemented.