A Victorian bathing machine - Seaford Town Museum 14 3 2020

Bathing machines were used on beaches in Victorian times to allow ladies to enter the sea water in a modest manner. They would enter through a door on the land side of the 'machine' and change into their swimming clothes. These were often costumes that completely covered their bodies. The machine would be rolled into the sea, sometimes by men and sometimes by a horse. Some just had steps so that the lady climbed into the sea, visibly but discretely. Others had screens on either side so that one could enter the water without being seen, except possibly by a maid who helped to dress and undress the swimmer.
Rows of 'machines' can be seen in this 19th century photograph - www.ipernity.com/doc/philsutters/26108827
Seaford Museum is housed in Martello Tower 74, on Seaford Esplanade.