Personal hygiene evolved rapidly at sea
During the age of sail sea voyages were long affairs, with large crews packed into crowded conditions for months and even years. Also during the age of sail, captains noticed an interesting phenomena. The longer they were separated from the shore, the healthier their crews became, with the exception of scurvy, not yet understood to be preventable through consumption of fresh vegetables and fruit. Captains at sea rid their ships of vermin by smoking them out, of rats and mice by entrapment and the use of cats and dogs as predators. And their men, exposed to the weather, were cleaner than their counterparts ashore. So were their living quarters, as captains strove more and more to enhance discipline through enforced cleanliness.
A month or so at sea and colds and influenza vanished from the ship. Crews found themselves bathed by freshwater from rain, and salt water from rough seas. Captains began the practice of airing out bedding, as well as clothes, allowing fresh air and sunshine to do its work on formerly dank, damp, blankets and trousers. Sailors relieved themselves over the side, and there were no festering latrines to draw flies and other pestilence. Upon entering port, sailors quickly availed themselves of the usually unhygienic pleasures available ashore, and once back at sea a shaking out period was often necessary before the ship, and the sailors aboard it, were once again clean. But they soon were. Medical professionals, such as there were at the time, took note of the health of the sailors, and for the first time the benefits of “salt air” became a subject of debate.