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.