@patowalker: I had hesitated to use "seaplane", but actually the Biscarrosse meeting is not on the sea, it is on a lake - and "lakeplane" might be puzzling, too! Will try to remember "hydroplane" for the next occasion.
@all: the "stone" was clear enough, though I had to search for the conversion factor; the "wet" was a bit more of a puzzle, but I could manage!