CHAPTER 4
BOILERS
The function of a boiler in the steam cycle is
to convert water into steam. Reliability in
operating naval boilers and associated equipment
is important for the power plant to operate at
maximum efficiency. The complex design of naval
boilers requires a high degree of technical
knowledge and skill on the part of the fireroom
personnel responsible for boiler operations. All
engineers should have some knowledge of the
principles of combustion, how combustion occurs
in a boiler, and the combustion requirements for
operating a boiler more efficiently. You may want
to review combustion in chapters 2 and 3 of this
textbook.
This chapter describes boilers commonly used
in propulsion plants of naval steam-driven
surface ships. This information is general in
nature and does not relate to any one class of ship.
Chapter 221 of the Naval Ships’ Technical Manual
is the basic doctrine reference on boilers. For
detailed information on the boilers in any
particular ship,
consult the manufacturer’s
technical manuals furnished with the boilers.
Upon completion of this chapter, you will
have the knowledge to be able to identify and
understand boiler terminology, the basic types of
naval boilers and their operating principles,
interpret gauges and indicators that aid in
monitoring operating parameters of naval boilers,
and understand boiler construction. You should
be able to identify the major parts of a boiler and
its functions. Also, you will learn about safety
precautions that must be observed during boiler
light-off.
BOILER TERMINOLOGY
Before studying the types of boilers used in
propulsion plants aboard Navy ships, you need
to know the boiler terms and definitions used most
frequently by shipboard personnel. In this section
we have listed some of the terms used in this
chapter and by fireroom personnel on the job. It
is not an all-inclusive list, but it will help form
a basis for your understanding of the information
presented on boilers.
Fireroom— The fireroom is a compartment
containing boilers and the operating station
for firing the boilers.
Boiler room— The boiler room is a
compartment containing boilers but not
containing the station for firing or
operating the boiler.
Main machinery room— The main
machinery room is a compartment con-
taining boilers and the station for firing or
operating the boilers and main propulsion
engines.
Boiler operating station— The boiler
operating station is a station from which
a boiler or boilers are operated, applying
particularly to the compartment from
which the boilers are operated.
Steaming hours— Steaming hours is the
time during which the boilers have fires
lighted until fires are secured.
Boiler full-power capacity— Boiler full-
power capacity is specified in the contract
specifications of a ship. It is expressed as
the number of pounds of steam generated
per hour at the pressure and temperature
required for all purposes to develop con-
tract shaft hp of the ship divided by the
number of boilers installed. Boiler full-
power capacity is listed in the design data
section of the manufacturer’s technical
manual for the boilers in each ship. It
may be listed either as the capacity at full
power or as the designed rate of actual
evaporation per boiler at full power.
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