Bonjour Bruce,
Good question.
As steamboat passionate since I was a young boy, my first steam plant and boat should have been this "Côte d'Emeraude" tug, Diesel in real life but designed for a Syuart D10 plant as model :
Quite too expensive for me at that time, I waited for more than 40 years to have mine.
My first steam plant and boat came for my 50th anniversary, a 1,20 m launch with a 3 è 7,5 cm3 JMC steam plant and already... a whistle

:
And now I am 66... And a too large fleet for my beloved wife !