turbine engine speed and has control levers similar
to an airplane throttle. The pitch lever provides
control of the propeller pitch angle. By varying
the pitch angle, the ships speed may be changed.
The pitch lever is graduated in feet of pitch either
ahead or astern.
CENTRAL CONTROL CONSOLE
The central control console is the primary
operating station for the propulsion plant and
is located in the CCS. The CCS is the main
engineering watch station. This console provides
the operator with the necessary controls and
displays for starting and stopping the gas turbine
engines. Controls on the central control console
allow the operator to vary the ships ahead or
astern speed within established design limitations
by changing the pitch of the propeller and the
speed of the propeller shaft.
The central control console (fig. 6-25) provides
two distinctly different methods of controlling the
ships progress through the water. The first
method requires the operator to individually
adjust three levers on the console. One lever
changes the direction and amount of pitch applied
at the ships variable-pitch propeller. Each of the
remaining two levers controls the speed of one of
the gas turbine engines. This is a duplicate set of
controls that are the same as the controls on the
local control console.
The second and primary method of operating
the ships propulsion plant involves the use of a
single control lever and a special-purpose digital
computer contained in the control system. This
technique for controlling the engines and the
propeller pitch with one control and the
digital computer is referred to as single-lever
Single-lever programmed control of the ships
propulsion plant can also be maintained from the
ship control console (SCC) located on the bridge.
However, the lever on the bridges SCC panel can
be operated only after the operator in the CCS
SHIP CONTROL CONSOLE
This station is located on the ships bridge.
This console has a throttle control, a propulsion
plant alarm, and shaft speed and propeller pitch
CONSOLE OPERATING OVERVIEW
Using modern electronics, computers, and
precisely placed sensing equipment, the operator
at the central control console can see and
manipulate the entire propulsion plant. The
operator is assisted by sensor-scanning equipment
that can check out the plant more thoroughly in
a fraction of a second than an engine-room
messenger could in 30 minutes. The scanning
circuits are wired with information about the
operating parameters of all the critical points
monitored and will sound off immediately if these
are exceeded. The operators control is extended
not only by remote operation of all engine
controls but also by wired-in expertise from
electronic components that know all the right
steps and procedures for all normal plant
operations as well as most emergency procedures.
There are two directions of information flow
in a gas turbine propulsion system. The first is
from the sensing and measuring devices on the
plant equipment. The second is from the operator
and the console to the engine control devices. The
first or input flow begins as an electrical signal
from a sensor. These signals are conditioned
so that they can be handled by the digital
computer. Some of the signals are displayed on
indicators at the operating stations. Most of these
indicators are for vital equipment functions.
The control of high-performance engines and
other machinery is a complex operation. Auto-
matic central-type operating systems permit a
single operator to perform this operation by
extending individual ability to sense and to
control. As these systems prove their effectiveness
and reliability, their use will increase.
DISADVANTAGES OF THE GAS
TURBINE PROPULSION SYSTEM
The gas turbine, when compared to other
types of engines, offers many advantages. Its
greatest asset is its high power-to-weight ratio.
This has made it, in the forms of turboprop or
turbojet engines, the preferred engine for aircraft.
Compared to the gasoline piston engine, which
has the next best power-to-weight characteristics,
the gas turbine operates on cheaper and safer fuel.
The smoothness of the gas turbine, compared with
reciprocating engines, has made it even more
desirable in aircraft because less vibration reduces
strains on the airframe. In a warship, the lack of