Naphtha Engines
Nothing, absolutely nothing, is quite so illicitly attractive to a Monotube enthusiast as a Naphtha engine.
Probably the best technical description is down to Douglas Self;
But surely all that Brass and copper, including the sheathing around the engine has something to do with it?
Even the funnel rim was a work of art, belying the utter simplicity of the boiler system. And don't think these launches were just a transient US Phenomenon, a Postcard photo of Teddington Lock dated 1899, shows at least three for hire on the Thames, and "Lady Elizabeth" a Windermere launch currently being restored, was probably imported from New York as a Naphtha launch.
Of course Naphtha as a medium has two important advantages, one it was lubricative and non rusting, which opens up the types of engine that you can employ, and the second point linking directly in to monotube water boilers is that Naphtha has a mix of components boiling at different temperatures. That greatly eases the feed pump requirements.
Of course there are problems, the main one being the loss of more volatile constituents to the burner, leaving an ever more paraffin like medium.
After the 120 years or so that have passed since these boats were around, it is hard to know the truth unless we build one ...............so watch this space!
The image on the left is taken from the Facebook page of Legacy of the lakes Museum which is available here.
Other sites that might be of interest include:
These various sources suggest that about six of the many thousand such mono-tube plants built between 1895 and 1905 still exist although only some of those are in working order.
Anybody with a yen to build one might like to consider the plans on offer at Mystic Seaport Museum where one of the surviving boats is on show. The plans are for the hull and plant offered by the Gas Engine & Power Company in 1904 and, as at October 2022, are offered for $50.