In the 1700's Europeans were still afraid to even swim, and picture our USn "Founding Fathers," Franklin and Washington, in those hot clothes never dousing for a full-bodied wash.

Do not denigrate my man Franklin , who was an excellent swimmer. (He is also credited with inventing swim fins.) Chapter V of his autobiography merits quote at length:

At Watts's printing-house I contracted an acquaintance with an ingenious young man, one Wygate, who, having wealthy relations, had been better educated than most printers ... I taught him and a friend of his to swim at twice going into the river, and they soon became good swimmers. They introduc'd me to some gentlemen from the country, who went to Chelsea by water to see the College and Don Saltero's curiosities. In our return, at the request of the company, whose curiosity Wygate had excited, I stripped and leaped into the river, and swam from near Chelsea to Blackfryar's, performing on the way many feats of activity, both upon and under water, that surpris'd and pleas'd those to whom they were novelties.

I had from a child been ever delighted with this exercise, had studied and practis'd all Thevenot's motions and positions, added some of my own, aiming at the graceful and easy as well as the useful. All these I took this occasion of exhibiting to the company, and was much flatter'd by their admiration ...
...
On one of these days, I was, to my surprise, sent for by a great man I knew only by name, a Sir William Wyndham, and I waited upon him. He had heard by some means or other of my swimming from Chelsea to Blackfriar's, and of my teaching Wygate and another young man to swim in a few hours.

He had two sons, about to set out on their travels; he wish'd to have them first taught swimming, and proposed to gratify me handsomely if I would teach them. ... I could not undertake it; but, from this incident, I thought it likely that, if I were to remain in England and open a swimming-school, I might get a good deal of money; and it struck me so strongly, that, had the overture been sooner made me, probably I should not so soon have returned to America. After many years, you and I had something of more importance to do with one of these sons of Sir William Wyndham, become Earl of Egremont, which I shall mention in its place.