This really depends on the area of origin. Greek sailors , for instance, were really good swimmers on average (recall Greece comprises several islands with "sho

This really depends on the area of origin. Greek sailors , for instance, were really good swimmers on average (recall Greece comprises several islands with "short" distances; fishing and sponge diving were/are also a side job for sailors and swimming was certainly part of a child's entertainment (a good source here is 19 century and later literature). I am not sure about the argument that falling in the water was a death sentence so that is the reason swimming was unnecessary. Consider that naval life for instance after the 14th century had a high accident rate. In such cases, being an above good swimmer is a highly desirable skill. I think the main reason for the lack of swimming was British and French sailors were "conscripted" in 18-19 centuries [0], and the average citizen at the time did not leave close to shore. At the time not living in close proximity to the sea practically meant, due to travel being a luxury of time (especially during the pre-enlightenment, i.e. feudalism, era), that you never learned to swim as a kid. That places a high-learning curve on an individual who does not have the luxury for such an investment. (Tried to find some credible research and reference; was disappointed with the material; Here is an article on the learning vantage point of an adult https://adequateman.deadspin.com/an-adults-guide-to-learning-to-swim-1718027248 https://adequateman.deadspin.com/an-adults-guide-to-learning...) Thus my point is that Feudalism [1] essentially removed access to the sea to people in mainland/central Europe during pre-adulthood, by land-locking families and later eras (industrialism) perpetuated this trend. Thus swimming became even more of a luxury, which is inline with the existence of a written manuals (certainly not aimed for the average citizen), that seem to focus on basic familiarity with the water. These seem similar to other luxury manuals at the time, such as fencing. Then the average sailor from these regions did not have prior familiarity with water. The time period the article focuses on is a post-Byzantium and post Venician era. I think the article kind of jumps ahead and focuses not on Western Europe but only on North and Central Europe. What was the "swimming state" of Roman era Germania or Britain? How can one draw conclusions about Northern Europe from the lack of access to baths in Rome? The reasoning of the article leaves a lot to be desired there. [0] https://en.wikipedia.org/wiki/Impressment https://en.wikipedia.org/wiki/Impressment [1] https://en.wikipedia.org/wiki/Feudalism https://en.wikipedia.org/wiki/Feudalism