USACE Field Research Facility
Field Research Facility
Coastal & Hydraulics Laboratory

LARC Survey | Vehicle | Equipment | Analysis and Software | Photos

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 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), adjusted according to wave conditions to obtain optimal data quality . 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.

To support survey operations, the operator's cab has been enlarged to provide space for the survey equipment and two additional personnel in a climate controlled environment. AC power for the survey equipment is supplied by a 5.2 kW (7 hp) diesel generator mounted below the deck of the vehicle. The generated AC power passes through a power conditioner and into a non-ferrous uninterrupted power source (UPS). The UPS output then feeds power to the survey equipment. This generator also powers the cabin air conditioning unit.

The Mechanical LARC-5

The FRF also operates a second, mechanical drive LARC. The second LARC is used for other tasks such as to deploy instruments, support diving activities, collect data, lay underwater cables and to tow a variety of sensors. An onboard davit and winch can lift 400 kg (900 lbs). A portable shed can be set on the open deck to support the electronics requirements of any type of sensor. The Army used the LARC to ferry supplies from boats to shore; when purchased by the FRF, the LARC was military surplus.

The LARC web pages were designed and created by Justin Vandever (Contract Student, Cornell University) with input from Bill Birkemeier, Dan Freer, and Carl Miller. July 2001.