History: Bathing Machine Devices On The Beach, 18th-19th Century, Europe

The bathing machine was part of etiquette for sea-bathing more rigorously enforced upon women than men but to be observed by both sexes among those who wished to be proper.
Especially in Britain, men and women were usually segregated, so nobody of the opposite sex might catch sight of them in their bathing suits, which (although extremely modest by modern standards) were not considered proper clothing in which to be seen.