REGISTERED MARINE TECHNICIAN
SURVEYOR & CONSULTANT on LARCS (LIGHTER AMPHIBIOUS RESUPPLY CARGO SHIPS) & DUKWS (DUCKS)
The LARCS were Army amphibious vehicle originally used in the 1960's
to ferry supplies from ships to shore. Its total possible load LARC-5
(5,000 lbs); LARC-15 (15,000 lbs); and LARC-60 (60,000 lbs.)
Although no longer manufactured, all three sizes LARC-5, LARC-15,
and LARC-60's still see service both within and outside the military.
There are three types of amphibians which are capable of traveling
over land or sea. The Lighter Amphibian Resupply Cargo V (LARC V)
is a small amphibian used primarily to carry items such as CONEXES
and other palletized cargo. The Amphibian Resupply Cargo (LARC XV)
is a little larger but still used for the same purpose. By the mid-1980s
most of these were located in Reserve units and were being phased
out of the system. The LARC LX was used in Vietnam and is capable
of carrying two 20-foot containers or one 40-foot container. Brig
Gen Frank Schaffer Besson returned to the US in 1948, and served
for nearly five years as Deputy Chief of Army Transportation. Besson
was promoted to Major General in 1950, and assumed command of the
US Army Transportation Center and School at Fort Eustis in 1953.
pioneered many concepts aimed at injecting greater speed and efficiency
into the transportation system. He used containerization, roll-on/
roll-off vessels, and improved amphibious vessels, such as the 5-ton
and 15-ton LARCS and the 60-ton BARC. The maiden voyage of the BARC
(barge, amphibious, resupply, cargo) was at Fort Lawton, Washington
in 1952. Maj. Gen. Besson, who was Chief of Army Transportation
from 1958 to 1962, was instrumental in the purchase of them. The
BARC stood for Barge Amphibious Resupply Cargo. Although no longer
manufactured, all three sizes LARC-5, LARC-15, and LARC-60's still
see service both within and outside the military.
There were 968 units originally built. As best records can indicate,
over 600 of them were sank, just as merely a means of disposal [when
the U.S. departed Vietnam in the '70s].
LARC-60 / LARC-LX / BARC
The BARC (barge, amphibious, resupply, cargo), later designated
as the LARC LX (Lighter, Amphibious, Resupply, Cargo), could carry
60 tons of cargo, and was used to transport wheeled and tracked
vehicles, including beach preparation equipment and general cargo
from ship to shore or to inland transfer points. It was the only
amphibian in the Army inventory capable of landing on a beach through
breaking surf. The BARC was deck-loaded on a commercial vessel of
heavy lift ship for transport overseas. The BARC had the ability
to operate on low strength soils at a gross weight of 319,000 pounds
(120,000-pound pay-load). It was capable of lightering 40-foot containers,
which can be discharged from the LARC by crane, narrow straddle
carriers, or rollers similar to those used in unloading cargo aircraft.
The maiden voyage of the BARC was at Fort Lawton, Washington in
1952. The four experimental BARCs were built by LeTourneau, Inc.,
which makes equipment much larger than the BARC, including off-shore
oil drilling platforms. The BARC was designed to carry a 60-ton
tank or fully equipped infantry company from ship to shore or back
where there was no fixed port. Its empty weight was 97 1/2 tons.
Its four tires were nine-and-a-half feet in diameter. It was 17-and-one-half
feet high and powered by four 265 horsepower GMC marine diesel engines.
Each engine drove one wheel on land. The two engines on each side
of the BARC coupled to drive one of the twin propellers in the water.
Top speed was 20 miles an hour on land and seven-and-a-half miles
an hour in the water.
The name was changed to LARC (Lighter, Amphibious, Resupply, Cargo)
in 1960. The LARC-60 transports wheeled and tracked vehicles, including
beach preparation equipment and general cargo from ship to shore
or to inland transfer points. It is the only amphibian in the Army
inventory, and the only vessel capable of landing on a beach through
a breaking surf. The LARC-60 can be deck-loaded on a commercial
vessel or heavy lift ship for transport overseas. It can be transported
on a semi-submersible vessel, in the well deck of an LSD, or aboard
THE LARC VEHICLE
The LARC-5 (Lighter Amphibious Resupply Cargo) is an Army amphibious vehicle
originally used in the 1960's to ferry supplies from ships to shore.
Its total possible load is 5 tons (hence the five after LARC). Although
no longer manufactured, all three sizes LARC-5, LARC-15, and LARC-60's
still see service both within and outside the military.
The FRF's Hydro-LARC is so named because it has been modified from
the original transmission, gear propeller, and drive shaft to a
hydraulic fluid drive system. The Caterpillar 3106 turbo diesel
engine is a 6-cylinder 223 kW (300 hp) engine that transfers hydraulic
fluid at 5515 kPa (800psi) or higher to hydraulic motors that power
all four of the wheels, the propeller, power steering, brakes, and
bilge pumps. The variable stroke feature of the pump allows an infinitely
variable gear ratio in either forward or reverse and constant engine
speed. The conversion to hydraulic power was done to increase reliability
and performance. The maximum speed of the LARC on land is 40 km/hr
(25 mph) and approximately 11 km/hr (6 knots) in water. Surveying
is typically conducted at a speed of 7 km/hr (4 knots), however,
the speed of the Hydro-LARC is adjusted according to wave conditions
to obtain optimal data quality . The typical offshore operating
range of the LARC is 8 km (5 miles). The LARC is 10.6 m (35 ft)
long, 3 m (10.2ft) wide, and 3.3 m (11 ft) tall. For use outside
of the immediate vicinity of the FRF, the LARC is loaded on a flat-bed
trailer and hauled to the site.
Characteristics and capabilities include the following:
Length overall: 63 feet.
Beam: 27 feet.
Displacement (weight): 88 light-tons.
Deck area: 527 square feet.
Payload: 60 tons.
Range: land, 60-ton load, 150 statue miles at 14 MPH; water, 60-ton
load, 75 nautical miles at 6 knots.
Draft: 7.5 feet (light); 9 feet (loaded).
The LARCS didn't take part in actual operations again until they
went to Vietnam to support the 101st Airborne Division in 1967 and
later the 1st Cavalry Division in 1968. During July 1968, at Wunder
Beach, the BARCS were running twenty-four hours a day. The 5th Mechanized
Division equipment, jeeps 3/4 and 2 1/2 ton trucks, M113, and M-60
tanks were arriving from the States aboard large ships called Seatrains.
The Seatrains would anchor close to shore, the bark would pull along
side and a M-60 tank or two M-113's would be lowered onto the deck.
The BARC would make a quick run to the shore, pull upon the beach,
drop the BARCS ramp and someone would drive the equipment from the
BARC on to the Republic of Vietnam. Maintenance on the BARC was
simple, keep the fuel, oil, and air filters clean and the four 761's
would run smooth as silk. This was the job the BARCS were designed
to accomplish and I remember the operation going off like clock
work. There was a control tower on the beach that kept an eye on
everything and directed everyone to the right places via radio.
It was mostly stress free for the operators. They would engage the
marine gear on the BARC when the stern touched the water and ease
the land transmission out of gear when the wheels no longer touched
Officials of at least two Army activities stated that the LARC-LX
had several advantages over the LACV-30 and that it should be considered
as an alternative to aquiring a new vessel. The LARC-LX is an amphibious
craft, and the Army had 36 of them in 1979. In its technical report
number 225, the Army Materiel Systems Analysis Activity stated that
despite its shortcomings in speed, the LARC-LX has no major deficiencies
and is probably the most versatile literate vessel in the current
inventory. Fuel consumption for its 60-ton cargo capacity is much
lower than for the 30-ton LACV-30. For nominal weights, the comparative
fuel consumption varies from 38 gallons per hour for the LARC-LX
to 260 gallons per hour for the LACV-30.
In a June 1978 memorandum, the Army Deputy Chief of Staff for Logistics
asked the Army Deputy Chief of Staff for Research and Development
if the LARC-LX has been seriously considered as an alternative to
the LACV-30. The Deputy Chief of Staff for Logistics stated that
the extremely high cost of the LACV-30 and the acceptable performance
of the LARC-LX seemed to dictate an objective comparison of cost
and capability factors. The memorandum also noted a number of advantages
of the LARC-LX over the LACV-30.
The LARC-LX had increased load capability. It will carry two military
vans or one 40-foot commercial container, and also will carry a
tank or any general cargo up to 100 tons in a limited overload mode.
LACV-30 will not carry 40-foot containers and can carry two military
vans only when lightly loaded. The LARC-LX is not affected by minor
slopes and surface gradations which cause major steering and maneuverability
problems for the LACV-30.
The LARC-LX was a proven product. Maintainability and costs to
support it are known. The degree of technical expertise of the crew
and the amount of time to train operators and mechanics for the
LARCLX can be satisfied with the "normal" pipeline soldier.
Crew members and mechanics for the LACV-30 were hand picked and
do not represent "average" soldiers normally received
by the basic unit through current induction and training cycles.
The sophistication and high cost of the LACV-30 suggest that some
system must be used to hand pick and extensively train crew members.
Shop and maintenance support areas were far less than required
for the LACV-30. No special hardstand is required as is mandatory
for the LACV-30 which literally creates a "sandstorm"
when moving across unimproved areas. The four engines in the LARC-LX
provide greater reliability than the two engines in the LACV-30.
The LARC-60 Maintenance Area at Ft. Story is the maintenance and
wash rack area for lighter age amphibious resupply cargo (LARC)
vehicles. During the 1950s, the area was first used as the barge
amphibious re-supply cargo (BARC) motor pool and maintenance facility.
In 1964, the BARC was phased out and the LARC was prototyped. In
1982, the LARC-60 facility was modified with the construction of
a concrete wash rack pad and surface water drainage control structures.
And now they are gone. The 309th Transportation (LARC LX) Company,
11th Transportation Battalion, was inactivated on 15 October 2001.
It was the last amphibious Company in the U.S. Army. The army now
depends entirely on conventional landing craft.