Here in Manhattan the water temperature today is 53 degrees, actually warmer than the air temperature (as I write) of 48. If we have a day of 70 degrees, which could happen before the end of the month, I hope get out for a paddle, wearing my wet suit. We are reaching the point, however, when one has to wear a dry suit, usually when the water temperature is 55.
The lady in this painting by French Realist artist Gustave Courbet, from 1865, is seated on a "podoscaphe." On page 108 of Velocipedes, Bicycles, and Tricycles by David Glasgow Velox, one learns that the podoscaphe is a marine velocipede, vélocipède marin in French. (This book, originally published in 1869, has been recently reprinted and is said to be an "unusual book [that] will appeal greatly to all who are interested in the history and manufacture of the bicycle.")
Picture credit: Ricci Art