I was looking at the engines for an early John Softley vessel MAGDALENA VICENTA and they were described as H4cyl (12.5 - 12.5ins), 20hp built by Hepple & Co. Would this be H for Horizontal (Kevin's normal state), 4 cylinders each of 12.5 ins diameter with a stroke of 12.5 ins? This was then somehow connected to a single shaft as she was a screw vessel.
I would appreciate any thoughts as engines are not my strong point.

OK Dave, Imagine Four of these, two either side connected to a Crankshaft.

There would probably be a big flywheel at one end of the Crankshaft and the propeller at the other end.

Lots more bits of pipe etc would be connected but I'm trying to keep it simple.........

Paul

Simple's good. So I guess this is before they had the technology to build an engine block. Thank you very much.

It might have had more to do with Headroom. You could fit this type of engine into a much smaller space.

Single Cylinder Steam Engines were very popular for Land Based Industrial installation's with steam being admitted to both sides of the piston so the Piston Rod pushed and pulled.

Large flywheels were fitted to keep the whole thing running smoothly. In addition the whole assembly could be fitted to a single Bedplate, elimninating the need for extra support.
It was somewhat unusual to see a horizontal engine with more than two pots.

Thanks Paul. I know where to come for engineering queries now.