| In some cases the damage control announcing system
(4MC)may be used as a primary means of communication.
Such a system consists of units located at the various
stations, which serve both as speakers and as
microphones. In many installed systems communication may
also be established with the bridge, conn, main control,
fire control, and lookouts. The operator in
damage-control station pushes a button when he wishes to
transmit, and releases the button to receive. A selector
switch enables him to make the conversation local, or to
make general announcements to all repair stations.
Advantages of the system include the fact that orders or
items of information are heard by all hands at a repair
station, thus eliminating possible errors on the part of
the station's talker. A wide range of selection is also
possible, since stations outside of damage control are
on the circuit. However, unless a routine of
broadcasting to all repair parties is followed, the
system of requiring all repair stations to keep a log of
all messages coming from control cannot be employed, and
the chain of control may be broken. Moreover, the 4MC
is dependent upon the ship's electrical circuits for
power, and are therefore more subject to battle damage
than the sound-powered circuits. |
