Over-The-Horizon Amphibious Operations: Will They Work?
AUTHOR Major R. R. Grider, USMC
CSC 1988
SUBJECT AREA Warfighting
EXECUTIVE SUMMARY
TITLE: OVER-THE-HORIZON AMPHIBIOUS OPERATIONS: WILL THEY WORK?
I. Purpose: To establish the validity of doctrine for conducting
over-the-horizon operations and whether or not this doctrine will
lend itself to conducting successful amphibious assaults.
II. Problem: The Navy and Marine Corps have developed an over-
the-horizon doctrine for conducting amphibious assaults due to the
advanced technology on the modern battlefield. Acceptance of this
doctrine without defining the many inherent problems contained
within it, could prove disastrous if the next amphibious assault
is conducted against a hostile beach.
III. Data: Since the Second World War, the Marine Corps has
continued to improve its capabilities to conduct amphibious oper-
ations through the procurement of new equipment and the advent
of modern technology. Similarly, the forces that the amphibious
task force will encounter on the beach will also have the
capability to inflict serious damage to the Task Force because
they too have new weapons and technology. Because of this, the
Navy and Marine Corps have adopted the doctrine of conducting
over-the-horizon assaults to ensure the success of the assault.
By conducting over-the-horizon assaults, the Navy does not
place its ships in "Harms Way", i.e. enemy target acquisition
capabilities, possible mined waters, avoidance of enemy shore
batteries while giving itself the ability to conduct surprise
landings due to the new equipment. Although a great idea, there
are inherent problems associated with the over-the-horizon
concept that could jeopardize future amphibious assaults. Commun-
ications, naval gunfire support and conventional landing craft
have basically outranged their capabilities. It is hard to
imagine an amphibious assault not being supported by naval gunfire.
Doctrine for the over-the-horizon landing has to be established
in order for the amphibious assault to be successful.
IV. Conclusions: The over-the-horizon doctrine changes the
perspective of the amphibious assault. With the Amphibious
Task Force out of communication, naval gunfire support and
conventional landing craft range, the potential for an unsuccess-
ful amphibious assault is very likely.
V. Recommendations: The Marine Corps and Navy must continue to
evaluate over-the-horizon operations and push for increased
budgeting to conduct research. The Navy must continue to push
for increased amphibious lift capability as well as increased
naval gunfire support platforms. More importantly, careful and
innovative thought will need to be given towards the over-the-
horizon concept because we have to utilize the assets presently
available to the Amphibious Task Force.
OVER-THE-HORIZON AMPHIBIOUS OPERATIONS:
WILL THEY WORK?
OUTLINE
Thesis Statement. Utilizing the over-the-horizon concept for
future amphibious operations that the Marine Corps may conduct,
are in jeopardy of being unsuccessful.
I. Amphibious Operations History
A. Marine Corps Amphibious Capabilities Part of the U.S.
National Strategy
B. Marine Corps Pioneers of Amphibious Doctrine
1. Often by Trial and Error
2. Extremely Complex Operation
C. Chief Disadvantage
1. Build-up of Combat Power Ashore
2. Difficult to Coordinate
a. Naval Gunfire
b. Communications
c. Follow-on Forces
D. New and Modern Equipment Now in Fleet
1. Landing Craft Air Cushioned (LCAC)
2. MV-22 Tilt Rotored Aircraft (Osprey)
II. Naval Gunfire Support
A. Description of Over-the-Horizon
B. Naval Gunfire Support Problems
1. Naval gunfire ships have outranged capabilities
2. Number of Naval Gunfire Platforms has Diminished
C. Traditional Concept of Naval Gunfire Not Viable
D. Discussion of Possible New Weapons
III. Discussion of Communications
A. Description of Required Tactical Nets
B. Amphibious Assault Will Be VHF Dependent
C. Discussion of HF Capabilities
1. Requires Complex Antenna System
2. Dependence on Atmospheric Conditions
D. Discussion of Communication Limitations and Effect
1. Build-Up of Logistical Requirements
2. Not Timely for Tactical and Helicopter
IV. A. Advantages to Navy
B. Advantages to Landing Force
C. Provides for Surprise
V. Discussion of LCAC
A. Capabilities
1. Ranges
2. Troop Capacity
3. Capabilities for Amphibious Task Force
B. Problems With LCAC
1. Lack of Amphibious Lift
2. Transit Time From Ship-to-Shore
VI. Discussion of MV-22
A. Capabilities
1. Range and Speed
2. Troop Capacity
B. Limitations
1. Flies Faster Than Cobra Gunships
2. May Have Tendency to Select Deeper Objectives
VII. Possible Naval Gunfire Solutions
A. Development of New Helicopters
B. Acquisition of Special Fire Support Landing Craft
C. Alternate Means to Project Assault Forces Ashore
VIII. Possible Communications Solutions
A. Messenger
B. Deception
C. Remotely Piloted Vehicle(RPV)
IX. Possible LCAC Solutions
A. Load AAV's Aboard LCAC's
1. Provides Mobility
2. Provides Firepower
B. Move Amphibious Ships Closer in
XI. Conclusion
OVER-THE-HORIZON AMPHIBIOUS OPERATIONS:
WILL THEY WORK?
The new over-the-horizon concept for future amphibious
operations is going to win future wars, so many experts
say. Utilizing the over-the-horizon concept for future amphi-
bious operations that the Marine Corps may conduct are in
jeopardy of being unsuccessful.
Since its earliest beginnings, the United States Marine
Corps, with its amphibious capabilities, has played an
integral part in the national strategy of the United States.
The ability to project power on foreign soils through
the concept of amphibious landings has been one of the
primary reasons for the success and existence of today's
Marine Corps.
Although having conducted numerous amphibious landings
since its inception, the Marine Corps became the real pioneers
of amphibious doctrine prior to and during the Second World
War. It was during this period that procedures for amphi-
bious operations were refined, often by trial and error.
Even then, amphibious operations were one of the most complex
operations to attempt. The chief disadvantage to a force
conducting an amphibious assault is the necessity to rapidly
build up its combat power from zero, to a level capable
of dealing with the threat. To be able to coordinate all
supporting fires prior to, during and after the amphibious
assault, plus ensuring that all the Marines and their
equipment are organized for the ship-to-shore movement
and finally to have follow-on forces and supplies link-up
with the assault echelon requires detailed and concurrent
planning at all levels.
Following the Second World War, the Marine Corps con-
tinued to improve its amphibious doctrine due to the advanced
technology. With all the improvements, have we made present
day amphibious doctrine so complex, that future amphibious
operations will end much like the attempt to rescue the
American hostages during "Desert One"? All the new concepts
and technology that are tied to present day amphibious
operations, such as "Over-The-Horizon", LCAC's (Landing
Cushion Air Craft)", and "Osprey (Tilt Rotored Aircraft)",
are nice to have and plan with, but are they really what
the Marine Corps needs? The past five years have been
ones of successful modernization and innovation, yet the
future holds many important challenges and opportunities.
There are inherent problems associated with conducting
over-the-horizon operations that when conducted in a peace-
time environment may not he highlighted, but when actually
conducted in a hostile environment, could prove to be disas-
terous. The coordination of all fire support assets, the ability
to gather intelligence, the build-up of combat power ashore
with the LCAC's and MV-22 Osprey and the ability to communicate
need to be closely scrutinized and evaluated.
An over-the-horizon landing, because of the distance
(normally twenty-five to fifty miles from the landing
beach), eliminates any possibility of close-in naval gunfire
support for the assault force. Since the Second World
War, the naval gunfire ships available for providing naval
gunfire support for the landing forces has diminished to
the point that normally only one ship is allocated per
infantry maneuver battalion.1 Now, with the over-the-
horizon concept of conducting amphibious landings, it is
unlikely that even these ships will be capable of providing
pre-D-Day fire support. The traditional concept of utilizing
naval gunfire for preparatory fires and for support of
the assault echelons until landing force artillery is
ashore will not work for an amphibious assault launched
from 25 to 50 miles of shore. Ships armed with 5-inch/54
caliber guns will not be able to reach targets without
moving to within visual range of the coastline, and by
doing so will compromise the surprise achieved by retaining
the task force beyond the horizon. Even the battleship,
with its 16 inch guns effective to 24 miles, will have
limited ability if stationed beyond the horizon.2
Congress, in Fiscal year 1984, mandated a study of
ways to improve NSFS capabilities, generally; later Congress
called for a second study concentrating on the need for a
dedicated NSFS ship. While numerous weapons and warheads
and alternatives have been proposed to meet required opera-
tional capabilities-a "navalized" version of the LTV/Army
Multiple Launch Rocket System (the "Assault Ballistic Rocket
System" or ABRS), reintroducing the 8-inch naval gun, Martin
Marietta's Patriot/Beachcomber missile, a navalized variant of
the LTV/Army Tactical Missile System (ATACMS), and the General
Dynamics conventional land attack Tomahawk cruise missile,
among others--the plethora of concepts may prove to be the
greatest obstacle in the selection of any one system to deploy. 3
It is easy to think about the possibility of procurring
new weapons systems to enhance Naval gunfire support capa-
bilities, or the possibility for the funding of new naval gunfire
support ships, but with the tightening of the defense budget,
it is unlikely that the Navy will allocate any of their
portion for procurement of these ships. If this procurement
doesn't occur, the problem of providing naval gunfire support
for the over-the-horizon concept will continue to be a problem.
If we are to succeed in an over-the-horizon assault, one
of the first problems that will confront the Amphibious Task
Force Commander will be his ability to provide communications
both during the ship-to-shore movement and during the initial
build-up of combat power ashore. The Marine Corps has the
capability to communicate from over-the-horizon, however, that
capability is limited aboard naval platforms. HQMC lists the
following nets as essential for an over-the-horizon assault:
Tactical Net (VHF)
Intelligence Net (VHF)
Fire Support coordination Net (VHF)
Logistics and Resupply Net (VHF/HF)
Naval Gunfire Support Net (HF)
Tactical Air Request Net (HF)
Helicopter Request Net (HF) 4
The dependence for VHF line-of-site short range communications
is dependent heavy. Because VHF is line-of-site, the landing
force is immediately placed in a position of being unable to control
the amphibious assault. Most of these nets are uncovered and
therefore can be easily intercepted and/or jammed. Furthermore,
because of the line-of-site factor, it becomes apparent that
with the over-the-horizon concept, the ships will be out of the
line-of-site capabilities of the VHF communications equipment.
When discussing the high frequency nets (HF), we look at
a net that gives us a long haul capability to conduct over-
the-horizon operations. However, HF requires a very complex
antenna array system in order to be effective. Inherent to
HF skywave transmission, is the creation of an HF skip zone
(loss of communications) that is dependent upon atmosphere
conditions and the distance between stations. The use of
near-vertical incident skywave (NVISW) antennae (0-300 miles)
solves the problem for Marine ground units, however, NVISW
antennae have not yet been installed aboard Navy ships.
Space available aboard ships, LCAC's and aircraft is limited.
Additionally the HF spectrum is congested worldwide, susceptable
to jamming and intercept, and is often disrupted by ionospheric
storms, all of which reduce reliability. 5
With these limitations, we are reducing the capability to
provide the logistical support for the build-up of combat power
ashore as well as the inability to provide timely tactical
air and helicopter support. It must be re-emphasized that
careful consideration has to be given towards the ability to
communicate in an over-the-horizon assault. The days of
amphibious shipping being only three-to-five miles away from
the assault beach are over with. With this no longer occurring
the VHF circuits have become ineffective and the HF circuits
continue to be questionable at best. The over-the-horizon
concept has certainly created problems that need to be resolved
if we are to communicate effectively.
As was mentioned earlier, the whole purpose for the creation
of over-the-horizon amphibious assaults is due primarily to the
advanced technology of todays weapons systems. With an over-the-
horizon landing, advantages for the Navy include:
--increased reaction time to air-launched cruise missiles.
--reduced ship vulnerability to deep and shallow water mines.
--reduced ship vulnerability to shore-based direct and
indirect fire weapons.
--increased capability to conduct feints
The Marine assault force will also enjoy increased
benefits as a result of this concept. Landing force advan-
tages include:
--The ability to attack at the time and place of our own
choosing.
--A shorter window of vulnerability while crossing the
beach.
--Access to more of the littoral due to increased stand-
off range.
--A widely dispersed enemy defensive posture. 6
While there are numerous advantages to the over-the-
horizon concept, there are several factors that will limit our
capability to mount an over-the-horizon assault. Due to the
range that assault craft have to travel, the operation will be
of long duration. This will be especially true if the Amphi-
bious Task Force stays over-the-horizon once the general off-
load phase of the operation begins.7 It is likely, however,
that the Amphibious Task Force will close with the beach,
following in trace of the LCAC's to reduce LCAC turnaround.
Another limitation is the lack of adequate shipping to carry
the 24 LCAC's required for a notional MEB to hit the beach.
Currently it is estimated that approximately 25 amphibious
ships will be required to support this task.
The over-the-horizon concept has been adopted because of
the advanced technology of weapons system and the ability for
Soviet Forces to defend large beachhead areas i.e. Motorized
Rifle Division can defend a 110 mile length of beach.8 The
Marine Corps, along with its Navy counterpart feels the LCAC
provides the ability to defeat this advanced technology and
the Soviet Forces ability to defend large beach frontages.
As discussed earlier, the over-the-horizon concept was
designed to provide the Amphibious Task Force Commander with
the ability to conduct feints as well as add surprise to
the exact location of the amphibious assault. The LCAC employs
hovercraft technology to skim across the ocean surface on a
cushion of air. It has a range of 2OO nautical miles and with
a full payload can travel at speeds in excess of 5O knots in
sea state 2 and 4O knots in sea state 3. Overloaded, it will
still achieve 3O knots in sea state 2. Unconstrained by winds,
tides, reefs, underwater obstacles, mines, beach gradients
and beach trafficability, the LCAC can cross the shoreline
and proceed inland at speeds up to 35 knots. Ashore, it will
cross 2O foot ditches and 5 foot vertical obstacles, knock
down small trees, and climb gradients up to 13 per cent.9
The most significant operational characteristics of the
LCAC are its speed and its ability to cross beaches that have
been unassailable. The LCAC will cross approximately 73 per cent
of the worlds coastline as compared to about 17 per cent for
conventional landing craft, enormously complicating a-defender's
task. Conventional landing craft and vehicles travel at speeds
of 8-11 knots. It is easy to see that technology has also played
a significant role in the amphibious landing much like the
modern technology has forced the Navy and Marine Corps to
adopt the over-the-horizon concept. With the innovation of the
LCAC, we are now making assumptions that, based on the LCAC's
capabilities, all problems for the over-the-horizon landing will
be conducted with little difficulty.
Presently there is only one ARG configuation that will
support the six LCAC's determined to be adequate to support
a MEU landing i.e. LPH, LPD, LSD, LST, LST, and then only if the
LSD is an LSD-41 class.10 Once launched, it is essential that
the momentum of an amphibious assault be maintained by the
rapid and continuing build-up of combat power ashore. Currently
if the amphibious assault is conducted from 2O miles offshore,
LCAC transit time to the beach will be about 3O minutes;
1O minutes will be required to offload in the handling site;
3O minutes transit time back to the ship; 2O minutes to enter
the welldeck; and 3O more minutes transit time back to the beach.
This all works out to an hour and a half between the time an
LCAC makes its initial landing and returns with a second
load. Turnaround time for a third load to the beach will be
further delayed because of the need to refuel the LCAC.11
Considering the amount of time required for LCAC turnaround,
it becomes apparent that the LCAC, although an excellent
piece of equipment, will not be effective if we conduct an
assault on a hostile beach. It does provide the capabilities
to conduct operations in a benign environment. There is no
question that the tactical doctrine for the LCAC needs to be
thought out prior to conducting an over-the-horizon assault.
Along with the LCAC that provides the surface assault
capabilities, technology is also providing the Marine Corps
with the MV-22 for rapid vertical assault capabilities. The
Osprey, one of the few successful joint-service programs, is
twice as fast as the CH-46 helicopter, can carry twice the
payload twice the distance, and it will significantly increase
the ability of Marine landing forces to carry out amphibious
landings from even greater off-shore distances than ever before.
The Osprey can ferry 32 fully equipped combat troops at speeds
of 25O knots over a range of more than lOO nautical miles.12
The general plans for their employment are not expected
to change much for those currently in use for helicopters.
There may be a tendency to select deeper objectives and landing
zones because of the increased speed of the MV22A. Because
of the nonavailability of naval gunfire and artillery, initial
reliance on air support will continue. These questions
need to be asked. Because of the early and exclusive reliance
on air support for the assault, will our air assets be over-
booked? What effect will the weather have on close air
support? Can air support be effective in the force of modern
air defense systems that have proliferated worldwide? Clearly
serious doubts exist as to whether adequate fire support can
be provided by any means projected to be available.13
MV-22 assaults will be faced with other problems. The
Cobra gunships, designed to accompany helicopter assaults and
provide limited fire support, travel at approximately 15O
knots. It won't be able to keep up with the MV-22. No
replacement or enhancement for the Cobra is planned to correct
this expected deficiency. The MV-22 will have a 1O,OOO pound
payload limit, thus it will not be able to carry the M-198
howitzer.14 Similar to the procurement of new Naval gunfire
ships, the tightening of the defense budget has also forced
the possibility of the MV-22 project being cancelled.
Clearly, there are numerous problems associated with
the concept of the over-the-horizon assault. The question
remains; are there solutions for the problems that have been
previously discussed? When discussing over-the-horizon, it
must be remembered that this is doctrine that will be solidified
by the mid 199O's, all of which is based on certain assumptions.
The first of these assumptions is that all the LCAC's and
MV-22 will be fielded and working within the fleet. Another
assumption is that there will be an increase in the amphibious
ship lift capability. And finally, the assumption that most
over-the-horizon assaults are to be conducted in a benign
environment.
In regard to fire support, possible solutions may include
the changing or restricting of weapons found with the
artillery, the development of new helicopter gunships,
the acquisition of special fire support landing craft, or
the development of alternate means of projecting assault
forces ashore. The Navy will have to continue to emphasize
the need for the funding of new naval gunfire support ships
as well as provide for an increase in amphibious shipping. New
weapons systems will need to be introduced. These solutions
for fire support are not something that can wait until the
199O's. They need to be planned for now, budgeted for now and
introduced to the fleet as soon as possible. If fire support
assets are not available for she landing force, the possibility
of a successful over-the-horizon assault are nonexistent.
The need to communicate will be essential if we are to
conduct a successful over-the-horizon assault. Possible solutions
begin with one of the primary means of communication, that of the
messenger. We must start establishing these messenger paths
now. Ship-to-shore message service should be established using
both LCAC's and helicopter assets that, are conducting sorties
between the Amphibious Task Force and the beachhead. We
should think through a thorough deception plan using LCAC's and
false target generation equipment and voice communications
deception, possibly forcing the enemy to commit his reserve
forces to a location other than the actual landing beaches.
We must take a hard look at the AN/PSC-3 manpack terminal that
provides the ability to communicate beyond the VHF line of
sites range. This radio is compatible with the AN/TSC-96
telecommunications terminal which will be employed ashore
by the landing force. With the development of surrogate
satellites that would or could be employed by aircraft, the
AN/PSC-3 can provide quick, reliable communications between the
Amphibious Task Force, attack aircraft, LCAC's and advance
forces.15 VHF voice tactical systems are ideal for over-the-
horizon concepts. The use of UHF/SATCOM provides connectivity
via satellite relay of ship-to-ship, ship-to-shore, and shore-to-
ship voice communications. The primary advantages to over-the-
horizon would be the command and control of advance forces,
LCAC's prior to and during the assault.16 Another possibility
for communications enhancement, may be the incorporation of
the Remotely Piloted Vehicle (RPV). Although current Navy policy
prohibits Navy RPV's from supporting the ship-to-shore assault,
the need for RPV's exists during this phase. RPV's could be
capable of providing critical intelligence support to the Amphi-
bious Task Force as the first LCAC sortie approaches the beach.
The development of a retransmission-capable RPV could also take
the burden off the helicopters and fixed wing assets tasked to
perform this function. 17
The key to a successful over-the-horizon launch is the
ability to communicate. If you can't communicate, you can't
maneuver, provide fire support, gather intelligence or rapidly
build up combat power ashore. Aside from the possible
solutions mentioned above, it is important that new methods
to communicate be explored and evaluated.
Possible solutions for the employment of the LCAC also
require innovative thought. Whatever the case, it is important
to understand that the LCAC provides the ability along with
the MV-22 for the rapid build up of combat power ashore. First
and foremost the key to successful use is to ensure that all
LCAC's and MV-22's are budgeted for, procurred and delivered to
the fleet as projected. In order to transport the LCAC, it is
also essential that the amphibious ship capability be enhanced
to be able to move a MEB or MEF. Without these two requirements
being accomplished, the over-the-horizon doctrine will never
be successful.
It is also important to work out the exact formula as
to what will be required to effectively build up combat power
ashore. This includes configurations of what to load on LCAC's.
Possibilities include moving the LCAC's ashore with troops
riding in Assault Amphibious Vehicles (AAV's). By doing this,
the assault troops are provided with both mobility and fire
support. The success of the over-the-horizon assault may also
require that the amphibious shipping move closer to shore during
the general off-loading to facilitate build up ashore. A third
solution would be to have the amphibious ships launch-the AAV's
behind the LCAC's. This would require those ships carrying the
AAV's to come in closer once the assault has started, however;
this too would facilitate rapid build up of combat power
ashore. These possible solutions for LCAC employment need
to be thought through, exercised and evaluated.
Having looked at the over-the-horizon doctrine for amphi-
bious operations, it is evident that there are many problems
associated with it. To be successful, it will require that
the Marine Corps and Navy continue to work through the many
problems that have been discussed throughout the paper. Many
of the solutions suggested in this paper will enhance this
doctrine if actively pursued, thereby enabling the MEB's and
MEF's who may eventually conduct the operations ashore, to
realize success rather than failure.
"FOOTNOTES"
1. Major Thomas A. Bailey, USMC, "Over-the-Horizon assault
by LCAC," Marine Corps Gazette (January 1986), p. 76.
2. Bailey, p. 76.
3. Scott C. Truver, "PHIBSTRIKE-95 Fact or Fiction?," Armed
Forces Journal (August 1987), p. 1O8.
4. Captain M.S. O'Neil, G.E. Hartway II and M. W. Roe, USMC,
"Communications for over-the-horizon assaults," Communications
Officers School, Quantico, Va., 1988.
5. O'Neil, Hartway II, and Roe, p. 8.
6. O'Neil, Hartway II, and Roe, p. 3.
7. O'Neil, Hartway II, and Roe, p. 3.
8. Truver, p. 1O4.
9. Bailey, p. 75.
1O. Bailey, p. 76.
11. Bailey, p. 77.
12. Joe Poyer, "Amphibious Warfare," International Combat Arms
(July 1987), P. 59.
13. Major James R. Wheeler, USMC, "Fire Support for Over-the-
Horizon Assault, " Marine Corps Gazette.(December 1986), p. 42.
14. Wheeler, p. 42.
15. O'Neil, Hartway II and Roe, p. 10.
16. O'Neil, Hartway II and Roe, p. IO.
17. O'Neil, Hartway II abd Roe, p. 24.
BIBLIOGRAPHY
!. Bailey, Thomas A., Major, USMC. "Over-the-horizon assault
by LCAC." Marine Corp Gazette (January 1986), 74-8O.
2. Green, Michael R. "New weapon systems for the U.S.
Marine Corps." Armada International (December 1985), 158-16O.
3. Lillie, Jay C., LtCol, USMC. "Seabasing the Harrier."
Marine Corps Gazette (May 1987), 78-83
4. O'Neil M.S., Hartway II G.E. and Roe, M.W., Captains, USMC,
"Communications for over-the-horizon assaults," Communications
Officers School, Quantico, Va. 1988.
5. Poyer, Joe. "Amphibious Warfare." International Combat
Arms (July 1987). 5O-59.
6. Reed, John. "Amphibious vehicles--to low a priority in
procurement plans." Armada International (April 1986), 1O8.
7. Truver, Scott C. "PHIBSTRIKE 95-Fact or Fiction." Armed
Forces Journal (August 1987), 1O2-1O8.
8. Wheeler, James R., Major, USMC. "Fire support for Over-the-
Horizon Assault." Marine Corps Gazette (December 1986), 38-43.
9. Whitehead, Andrew, Colonel, British Royal Marines. "Over
the beach: Amphibious Operations in the 198O's-199O's."
NATO's Sixteen Nations (October 1986), 58-6O.
1O. Wilson, Peter A., "The Marine Corps in 1995" U.S. Naval
Institute Proceedings (November 1985), 52-61.
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