Col. James Sorrel, of CA, utilized commercial piston and cylinder assemblies to produce his custom-built 2-cylinder racing engines. For boating applications his designs required removing the cylinder fins and seating the cylinder into machined aluminum crankcases for water cooling. It is not known how many model engines he produced, but most known examples are water-cooled and designed for model boats.
Sorrel 2-Cylinder Inline Model Boat Engine
