Steam boilers are used either as main machinery for propulsion, as in
Steam Ships, or as auxiliary machinery in Motor Ships.
Because of this
difference, the size and pressures of the steam boilers in Steam Ships
will be very much larger than that in Motor Ships. The dryness of the
steam produced will also be different.
Basically, the boiler is a huge pressurized kettle, using fire to heat
water to a boil and extracting the steam. The steam is used to channel
heat energy from the fire to power machines, or to heat remotely located
All the steamships use water tube boilers because of the higher pressures,
but many motorships use fire tube boilers for lower pressures.
exception is the boilers installed in oil tankers. These are often water
tube boilers because of the higher demand for steam on these ships.
Care must be taken to condition the water in the boiler to prevent
scaling, and corrosion, which can weaken the pressure vessel. With the use
of heavy oil for fuel, it is also very important to ensure that the
surfaces exposed to the fire are free of soot deposits and sulfur
The burners usually require the most maintenance, as this is the place
where the heat from the fire can carbonize the oil to form deposits.
The steam boiler is part of a closed loop steam system, whereby, after the
energy of the steam is used up and it becomes water again, the latter is
collected and returned back to the boiler for heating up again to steam.
Any leakages in the system will have to be replenished with fresh water.