Powered by Boiling Petrol.> Incredible as it may seem, around
the end of the nineteenth century, small boats really were
powered by boiling petrol and using the vapour to drive a sort
of "steam" engine. The "petrol" was more often called "naptha"
at the time, and was a mixture of low-boiling point hydrocarbons
distilled directly from crude oil rather than the sophisticated
brew we know as "petrol" nowadays. The literature of the day
used both terms pretty much interchangeably, and I have done the
same here. The naptha was boiled by burning a certain proportion
of the working fluid, ie naptha. At first I thought that the
designs below were merely optimistic proposals, but further
research has shown that "naptha launches" really did exist,
though in what numbers I cannot presently say. Certainly they
were recreational craft for the rich rather than working boats.
I initially thought that naptha was adopted as a working fluid
because it boiled at a lower temperature than water, and so was
thought to be more effi