Whilst it may be a nice, but small, piece of social history to learn that in 1891, Thomas Piot applied for a British patent on a toy boat he constructed, sadly the man himself faded into obscurity.
What is interesting for us however, is that the principle for propulsion is returning pressure wave action. Perhaps with this simple little tin boat the first stirrings of expansion chamber function was kindled?
Google.......Desire Thomas Piot; The whole story is there, and its interesting stuff, anything that may involve pressure waves is worth looking at, see what you think, have a go at making one!
Trevor