CHAPTER 7
LCAC AND PHM PROPULSION SYSTEMS
The GSEs assigned to landing craft, air cushion
bow thrusters and two aerodynamic rudders. Figure 7-1
is an illustration of an LCAC craft.
(LCAC) vessels and patrol combatant missile
(hydrofoil) (PHM) class ships are responsible for the
The LCAC engineering plant consists of
upkeep and maintenance of the propulsion electronic
propulsion, lift, and control systems. The plant is
control systems. If you are assigned to an LCAC or a
operated by the craft engineer/assistant operator while
PHM, the watches you will stand will be different from
the craft is underway. There are no traditional watches
those on the DD-963, DDG-993, DDG-51, CG-47, and
as these limited endurance craft carry only enough
FFG-7 class ships. In this chapter you will read about
personnel to man the operating stations. The crew
some of these differences and the associated
consists of an operator, craft engineer/assistant operator,
responsibilities you may be expected to assume.
navigator, load master, and deck hand/engineer. This
small crew is completely responsible for underway
After reading this chapter, you should be familiar
operations, and embarkation and disembarkation of
with the operation of the engineering plant equipment
troops and supplies. The only GS is the craft
on the LCAC and PHM class ships. The information
engineer/assistant operator.
p r e s e n t e d in this TRAMAN is designed only to
familiarize you with the equipment on these ships.
In the following paragraphs, we will describe the
Remember, you should always use the appropriate
basic physical and functional characteristics of the
EOSS and PQS to qualify for a particular watch station.
LCAC control systems. The LCAC control systems
After reading this chapter and completing the
include all the systems and controls the operator needs
associated self-study questions in the NRTC, you should
to maneuver the craft. Maneuvering an LCAC basically
have acquired enough knowledge to begin qualifying at
consists of controlling the craft's direction, speed, and
the individual watch stations on board these ships. Even
cushion.
though you may never be assigned to an LCAC or PHM,
the information in this chapter should familiarize you
The LCAC control systems are divided into the
enough with the equipment to help you advance in the
following subsystems:
GSE rating. As you become more senior in the GS
1
Steering control system
rating, you may find yourself assigned to an LCAC or
✎
PHM class ship, or to one of their maintenance depots.
2 Propeller pitch control system
✎
In either case, this indoctrination could help you begin
3 Lift fan control system
your qualifications.
✎
4 Lycoming TF40B engine control system
✎
LANDING CRAFT, AIR CUSHION
5
Command and control keyboard
✎
The LCAC is a high-speed, ship-to-shore,
6 Rate of turn system
✎
over-the-beach vehicle that will deliver a 60-ton payload
7
Outside air temperature system
✎
to the ground elements of a Marine amphibious force. It
provides the Navy and Marine Corps with high-speed
8
Speed/sideslip indicator
✎
delivery capabilities to support amphibious operations.
These subsystems are controlled by the operator in
The LCAC is an air cushion vehicle that is powered
the LCAC operator station command module or the
operator in the engineer control station. Figure 7-2
by four AVCO Aerospace TF40B marine gas turbines
shows the physical arrangement of a typical LCAC
that provide a total of 15,820 horsepower (hp). Two
shrouded reversible pitch propellers `provide forward
operator station command module. Now, let's take a
brief look at each of these subsystems and how they are
and reverse motion. The air cushion on which the craft
used. After we look at the control systems, we will
rides is created by four double-entry fans. These fans are
63 inches in diameter, providing the desired amount of
discuss the electrical system that provides the electrical
power for these units.
airflow. The steering system consists of two rotatable
7-1
