This is the earliest version of the Mamod marine engine. The later 1958 version of the ME1 can be seen here. It has a flat base instead of the later pressed chassis, and it has a different unshrouded design of firebox.The boiler is 1 1/2" dia x 4". It has no water level indication. The only boiler fittings are safety valve and a steam dome. It is mounted in traditional manner over a two wick meths burner. The steam pipe exits from the side of the dome and, without any superheating, directly to the engine unit.
The cylinder is a single acting oscillating cylinder type, mounted almost vertically on a cast frame. Bore is 5/16" and stroke 1/2". The engine unit is slightly inclined backwards so that the propeller shaft angles down through the base plate (and hence through the bottom of the hull when installed). The propeller shaft is inside a 1/4" diameter brass tube and has a 1" diameter brass flywheel on the cylinder end and a 1 1/4" cast brass 2 blade propeller at the lower end.This engine has been functionally restored by the previous owner. He first acquired it as just an engine and base, and later acquired a boiler, firebox and burner (all correct, I believe). He made replacement parts for the pipework and other small missing parts.