hydraulic-operated switch, the active steering controller
Steering Control System
of the unit acts as an LVR type, while the backup unit is
set to operate as an LVP type. This results in the
The steering control system provides rudder
automatic restarting of the active unit after recovering
command inputs to the mechanical differentials which
from a loss of power. Should the active unit fail to
provide a mechanical rudder position command input to
restart, the steering watch stander can manually start the
each hydraulic system.
Rudder Angle Display System
The rudder angle display system provides rudder
position information to those personnel concerned with
The basic force used to operate the rudders is the
the ship conning tasks.
pressure of the hydraulic fluid from the steering pumps.
The array of valves, piping, sensors, and controls is used
Rudder Angle Order System
to send this fluid under pressure to the appropriate point
to achieve the desired change in rudder position. What
The rudder angle order system provides a nonverbal
follows is the means by which this is accomplished.
means of communicating rudder commands from the
pilot house SCC to the steering gear room ASCU and
Description of Operation
Movement of twin rudders is provided through
Helm Wheel Angle Indicator
movement of port and starboard single-ram,
mechanical] y independent, slide-type steering gears
The helm wheel angle indicator provides a
located in the steering gear room. Each hydraulic
mechanical indication of the rudder command position
system is controlled by a mechanical differential which
of the helm wheel or knob.
provides a summing function to operate the hydraulic
pump stroking mechanism.
Ram and Follow-up Assembly
Each power unit hydraulic pump and electric pump
is mechanically mated by a keyed coupling joining the
The ram and follow-up assembly is a mechanical
respective shafts. The command module, differential
arrangement of components connected to the rudder
control assembly, and remote control servo units
stock crosshead. The assembly reacts to hydraulic
(RCSUs) are clustered on a support bracket which is
pressure developed by the power units, causing radial
mounted to the ship's foundation and positioned at the
movement of the rudders.
A rudder angle order signal from the SCC drives a gear
Hydraulic Power Unit Control System
train and cam assembly in the RSCU to position the
mechanical differential output shaft. The output shaft is
The hydraulic power unit control system remotely
linked to a pump control module which positions the
and locally controls and monitors the operation of the
control valve which "strokes" the pump.
four hydraulic power units. Each power unit consists of
an electric motor directly coupled to a variable delivery
As you read this section, refer to the block diagram
hydraulic pump. Each power units electric motor is
shown in figure 5-42. Once a rudder command is
individually controlled by an associated 440-volt ac,
initiated from the steering control console, a signal is
three-phase, bulkhead-mounted motor controller.
transmitted to the RCSU. The RCSU, which has its own
internal control loop, drives its servo motor to the proper
position to set the cam of the steering gear mechanical
Four motor controllers, one for each steering pump
differential so that the steering gear is ordered to move
motor, are mounted on the forward bulkhead of the
the rudder in the desired position. As the cam of the
steering gear room. Control of the steering motors may
mechanical differential is moved, it puts the variable
be switched at its controller from OFF to LOCAL or
delivery pump "on stroke." The on stroke pump
provides hydraulic pressure through the automatic
transfer valve to the appropriate side of the ram cylinder,
Each controller may be setup to act as an LVR- or
which moves the ram in the desired direction.
LVP-type controller. Through the operation of a