sprinkling systems, flushing systems, machinery-
cooling water systems, washdown systems, and
other systems as required. The fire-main system
is used primarily to supply the fireplug and the
sprinkling system; the other uses of the system are
secondary.
Naval ships have three basic types of fire-main
systems: the single-main system, the horizontal-
loop system, and the vertical-loop system. The
type of fire-main system in any particular ship
depends upon the characteristics and functions of
the ship. Small ships generally have straight-line,
single-main systems. Large ships usually have one
of the loop systems or a composite system, which
is some combination or variation of the following
three basic types:
The single-main fire-main system consists
of one main that extends fore and aft. The main
is generally installed near the centerline of
the ship, extending forward and aft as far as
necessary.
The horizontal-loop fire-main system con-
sists of two single fore-and-aft, cross-connected
mains. The two mains are installed in the same
horizontal plane but are separated athwartships
as far as practical.
The vertical-loop fire-main system consists
of two single fore-and-aft, cross-connected mains.
The two mains are separated both horizontally
and vertically. As a rule, the lower main is located
below the lowest complete watertight deck, and
the upper main is located below the highest
complete watertight deck.
A composite fire-main system consists of
two mains installed on the damage control deck
and separated athwartships. A bypass main is
installed at the lower level near the centerline.
Cross connections are installed alternately between
one service main and the bypass main.
Communications Equipment
Damage control communications are vital to
a ship’s survival during emergency conditions. If
adequate damage control (DC) communications
are not maintained, the entire DC organization
could break down rapidly and fail to perform its
primary functions.
The following communication methods are
used for DC communications:
Sound-powered battle telephone circuits
Interstation two-way intercoms
Ship’s service telephones
Ship’s loud speaker or general announcing
system
Voice tubes
Messengers
Detailed information on each method can be
found in Damage Controlman 3 & 2, NAVED-
TRA 10572.
Electrical Systems
DCPOs perform periodic maintenance (PM)
on electrical systems within their division spaces.
They must know the location of fuse boxes and
circuit breakers that control the circuits. Proper
tag out procedures are also required to prevent
harm to other crew members while the PM is
performed.
You should be able to identify the following
electrical systems in your areas:
Lighting
Lighting panels
Electrical power outlets
Motors and fans
Casualty power terminals and panels
Battle lanterns
Watertight Closures
The watertight integrity of a naval ship is
established when the ship is built. This original
watertight integrity may be reduced or destroyed
through enemy action, storm damage, collision,
standing, or negligence. As a duty DCPO, you
will be responsible for ensuring the proper
material condition is set. Later in this chapter we
will discuss in depth the material conditions and
required reports.
7-6
