The CRP propeller system for the propulsion
An air filter (shown on fig. 8-l) is provided
shaft consists of the propeller blades and hub
at the output of the propeller shaft brake panel
assembly, the propulsion shafting, hydraulic and
to provide constant filtering of the air applied to
pneumatic piping and the control rod contained
the propeller shaft brakes. This air filter contains
in the shaft, the HOPM, the OD box, the
a replaceable element.
control valve manifold block, the electrohydraulic
controls, the hydraulic oil sump tank, and the
head tank. Figure 8-20 shows a block diagram of
CONTROLLABLE PITCH
the system.
PROPELLER SYSTEMS
The CRP propeller has five blades. The blade
pitch control hydraulic servomotor, mechanical
The ship's propulsive thrust is provided by a
linkage, and hydraulic oil regulating valve are
hydraulically actuated propeller or propellers,
housed in the propeller hub/blade assembly.
depending on the class of ship. Each propeller is
High-pressure hydraulic control oil is provided for
driven by two GTEs through a reduction gear
each propeller by the HOPM that is located
assembly and line shaft as previously described.
adjacent to the reduction gear. An OD box,
Since the GTEs cannot be reversed, the CRP
mounted on the forward end of the reduction
propellers provide both ahead and astern thrust,
gear, is mechanically connected to the hydraulic
thus eliminating the need for a reversing gear. The
oil regulating valve by a valve control rod. The
following description of the CRP system is based
OD box contains the hydraulic servomechanism
on the DD-963 class ships; systems on the
that positions the regulating valve rod. The OD
DDG-993 and CG-47 class ships are basically the
box also provides the flow path connection
same as the controllable pitch propeller (CPP)
between the hub servomotor and the HOPM. The
system on the FFG class ships. For a more
regulating valve control rod, PA piping, and the
thorough description of your ship's system, check
flow path for the hydraulic oil supply and return
the shipboard technical manuals and ship's
are contained in the hollow propulsion shafting.
information books.
Figure 8-20.--CRP propeller system block diagram.
8-30
