CHAPTER 7 TRACTOR-TRAILERS AND DUMP TRUCKS

Tractor-trailers and dump trucks are used to haul equipment, construction supplies, and materials used to support construction operations, disaster recovery operations, the preventive maintenance program, and so forth. This chapter covers the basic principles of tractor-trailer and dump truck operations.

TRACTOR-TRAILERS

Thousands of miles of tractor-trailer operations are generated during a deployment. These operations include the hauling of equipment and construction supplies in support of NMCB/NCF tasking. You, as an operator, must remember that when tractor-trailers are on the open road, they represent the U.S. Navy and the Seabees to the public.

The tractor, technically known as a truck-tractor, may have a gasoline- or diesel-powered engine, be equipped with an automatic or manual transmission, and range in capacity from 5 tons through 25 tons. Some examples are shown in figure 7-1.

NOTE: Because of the variety of transmission types in truck-tractors used by the NCF, it is important that you study the operator's manual before operating a certain model of truck-tractor. The operator manuals are located in the Technical Library.

Operator's errors, such as grinding gears while shifting, clutch slipping, rapid engagement during shifting, improper downshifting, and so forth, often cause premature failure of drive-line components, resulting in needless downtime and delays in production.

TYPES OF TRAILERS

The NCF uses a variety of trailers to support the mission of the NMCB. Before using any trailer, know all safety precautions, and check the manufacturer's recommendations for loading requirements, and weight restrictions. This is important because the OPERATOR IS RESPONSIBLE for the safe loading, securing, and operation of the tractor-trailer.

^{Figure 7-1 .-Truck-tractors.}

Van Trailer

A van trailer (fig. 7-2) is fully enclosed with permanent sides and top to keep the inside of the trailer dry and is manufactured with two basic types of doors. One type is the swing open and the other is the roll-up. In some cases, a trailer may have another door on the side. In the NCF, some of the van trailers have been modified to carry different types of cargo.

You may have to operate a refrigerated van trailer. The construction of a refrigerated van trailer is similar to the van, except it has a self-contained refrigeration unit built onto it.

Stake Trailer

The stake trailer (fig. 7-3) is often identified by the term flatbed and is designed for cargo that cannot fit

Figure 7-2.-Van trailer.

Figure 7-3.-Stake trailer.

Figure 7-4.-Low-bed trailer.

Figure 7-5.-Tilt-bed trailer.

through the doors of a van trailer. Stake trailers are easy to load and unload with forklifts from the side when the side stakes are removed. Any loads that extend over the width or length of the flatbed must be visually marked with a flag during the day and lights at night.

NOTE: Side stakes are collateral equipage for the stake trailer. The operator is responsible for the side stakes if they are removed, broken, or lost. When the side stakes are removed for storage, ensure the stakes are tagged with the USN number of the trailer. Damaged, lost, and in some cases stolen stakes should be reported immediately through your chain of command.