The triple-expansion piston engine is the first kind of steam engine. It consists of a positive displacement engine capable of transforming the thermal energy produced in the boilers into mechanical energy.
For the ship to be ready to sail, a period of at least twenty hours is required from the moment the Chief Engineer provides for the lighting of the burners, a task usually performed by the Stoker. This amount of time is needed for the water in the system to reach operating pressure. Two double-burner units were installed in 1953, the only major alteration made to the propulsion system in the Pietro Micca's 100 and more years of history; thus the ship changed from coal to oil-firing. All the auxiliary equipment is steam-powered: the capstan for weighing the anchor, the windlass for winding cables, the electric generator. Even the rudder is servo-assisted by steam power. At a stable rate of 87 rpm the Pietro Micca can maintain a cruising speed of 10 knots, giving her an autonomy of 2400 miles for a fuel consumption of four tonnes every twenty-four hours. The fuel storage capacity in the main, ancillary and reserve tanks total 40 tonnes, while two other large tanks contain thirty tonnes of water for use in the boilers.
To recharge the ship's batteries, in addition to the steam-powered generator this year a number of photovoltaic solar panels (1.3kw/day) have been installed, thus permitting the ship to take advantage of a modern technology while losing nothing of her traditional appearance and compatibility with the environment.
Presentation - Technical characteristics - The History - The shipyard - Link - Home Page e-mail: pietromicca@tecnomar.net