The D48 is intended to be built into a boat hull. It consists of separate boiler and engine units, which I have mounted on a wooden base for convenience.
The boiler is 55mm diameter x 133mm. It has a butane fired burner, fed from an external thin cylindrical tank fitted with a valve and jet, which is aimed into the burner fixed under the boiler. There is a circular water gauge window in one end and on the top of the boiler there is a safety valve and a filler plug. There is a short open ended steam feed pipe intended to be connected to a similar pipe on the engine unit using a plastic pipe section. There is no steam valve but the engine speed can be controlled, to a certain extent, by the gas control or the reverser.
The engine is on a separate chassis, mounted on an adjustable tilting bracket. It is twin cylinder, double acting with Wilesco style slide valves (described by Wilesco as a "piston" valve). They are approx 13mm bore x 16mm stroke. There is a simple lubricator fitted to each valve chest. Reversing is acheived by swapping the inlet and exhaust (unusual for fixed cylinders and would not be possible with traditional slide valves). The reversing valve is fitted with a lever adapted for remote control. The crankshaft is geared to the output shaft to enable a prop shaft to be connected.