PATROL COMBATANT MISSILE
Specialized Repair Facility
(HYDROFOIL)
Specialized repair facility maintenance is normally
The PHM is an advanced design, fast, highly
accomplished at a shore facility that has the specialized
maneuverable, foilborne warship. The mission of the
capabilities required for specific parts that need
PHM is to operate offensively against hostile,
maintenance actions beyond the scope provided by the
heavy-surface combatants and other surface craft and to
depot maintenance level.
conduct surveillance operations, such as screening
Now that we have talked about the different
coastal convoys or amphibious forces in the arrival and
departure areas. This small, fast, and versatile ship
maintenance levels, let's look at some of the trouble-
shooting procedures you may need in maintaining the
provides the Navy with high-speed support capabilities.
LCAC control equipment and systems.
The basic design of the PHM is shown in figure
6-19. This design offers the stability and ride comfort
normally limited to much larger ships at a much lower
TROUBLESHOOTING PROCEDURES
cost. It also offers the high maneuverability and speed
associated with smaller vessels. Its propulsion system
In troubleshooting the components and systems of
consists of both a foilborne and a hullborne system. This
the LCAC, you will use the basic troubleshooting
combination design offers the advantages of a diesel
methodology we discussed earlier in this TRAMAN.
engine in its economical, long-range cruising and
Sometimes, system analysis will allow you to go
close-in, low-speed, twin-engine maneuvering ability
directly to a specific faulty component or cable. When
and those of a lightweight GTE in its immediate,
you need to use a more comprehensive process,
high-speed, foilborne capabilities. Its maximum
however, the half-split method of troubleshooting will
hullborne range is greater than 1,200 nautical miles with
provide you with the most logical approach to fault
a maximum speed of 11 knots. While the craft's takeoff
isolation.
speed is dependent on the loading, sea state, and power
settings of its controls, its maximum foilborne speed is
To perform the half-split method of fault isolation,
greater than 40 knots with a maximum cruising range of
you should first pick a circuit midpoint on a specific
greater than 500 nautical miles.
wiring diagram. Your ability to gain access to this
midpoint should be the determining factor. By taking a
As we discuss the PHM, we will provide you with
signal measurement at the midpoint, you will be able to
a general description of the physical and functional
determine which half of the circuit is defective. After
characteristics of its propulsion systems and controlling
you determine a midpoint, refer to the wiring diagram
stations. The basic control system includes the systems,
to identify the signal level or range required. If the signal
controls, and equipment needed for direction, speed, and
is correct at the midpoint, then the defective part or
other maneuvering operations. Its propulsion and
circuit lies somewhere between that point and the end
auxiliary systems include the following six subsystems:
of the circuit. If the signal made at the midpoint is not
1. Main propulsion (foilborne) subsystem
connect, the problem lies somewhere between that point
and the point at which the signal starts. Your next step
2. Main propulsion (hullborne) subsystem
is to continue to use the half-split method on the part of
3. Power train subsystem
the original circuit you have found to be defective.
4. Automatic control subsystem
You should continue this process until you can
isolate the defective part or area. In the last stage of the
5. Electrical subsystem (ship's service power unit)
half-split method, you should be able to isolate the fault
6. Auxiliary subsystems
to a specific component or part of the circuit. At this
In the following paragraphs, we will briefly describe
point, you should use a voltage and continuity check to
these systems and how they work to propel and control
confirm the specific cause of the problem.
the craft.
In the preceding sections of this TRAMAN, you
have read about the design, control systems, and basic
maintenance you will encounter in your duties and
PROPULSION SYSTEMS
responsibilities aboard an LCAC. Now, let's look at the
The PHM has two complete and separate main
propulsion system of another type of landing craft, the
propulsion systems: (1) the foil borne system and (2) the
patrol combatant missile (hydrofoil) or PHM.
