SLINGS AND RIGGING GEAR KITS

The NCF has slings and rigging gear in the battalion Table of Allowance to support the rigging operations and the lifting of CESE. The kits 80104, 84003, and 84004 must remain in the custody of the supply officer in the central toolroom (CTR). The designated embarktion staff and the crane test director monitor the condition of the rigging gear. The crane crew supervisor normally has the responsibility to inventory the contents of the kits. The rigging kits must be stored undercover.

WIRE ROPE SLINGS

Wire rope slings offer advantantges of both strength and flexibility. These qualities make wire rope adequate to meet the requirements of most crane hoisting jobs; therefore, you will use wire rope slings more frequently than fiber line or chain slings.

FIBER LlNE SLINGS

Fiber line slings are flexible and protect the finished material more than do wire rope sliings. But fiber line slings are not as strong as wire rope or chain slings. Also, fine line is more likely to be damaged by sharp edges on the material being hoisted than wire rope or chain slings.

CHAIN SLINGS

Chain slings are frequently used for hoisting heavy steel items, such as rails, pipes, beams, and angles. They are also handy for slinging hot loads and handling loads with sharp edges that might cut the wire rope.

USING WIRE ROPE AND FIBER LINE SLINGS

Three types of fiber line and wire rope slings commonly used for lifting a loud are the endless, single leg, and bridle slings.

An endless sling, usually referred to by the term sling, can be made by splicing the ends of a piece of fiber line or wire rope to form an endless loop. An endless sling is easy to handle and can be used as a choker hitch (fig. 13-30).

Figure 13-30.-Endless sling rigged as a choker hitch.

Figure 13-31.-Methods of using single-leg slings.

A single-leg sling, commonly referred to as a strap, can be made by forming a spliced eye in each end of a piece of fiber line or wire rope. Sometimes the ends of a piece oe wire rope are spliced into eyes around thimbles, and one eye is fastened to a hook with a shackle. With this arrangement, the shackle and hook are removable.

Figure 13-32.-Multi-legged bridle slings.

The single-leg sling may be used as a choker hitch (fig. 13-31, view A) in hoisting by passing one eye through the other eye and over the hoisting hook. The single-leg sling is also useful as a double-anchor hitch (fig. 13-31, view B). The double-anchor hitch works well for hoisting drums or other cylindrical objects where a sling must tighten itself under strain and lift by friction against the sides of the object.

Single-leg slings can be used to make various types of bridles. Three common uses of bridles are shown in figure 13-32. Either two or more single slings may be used for a given combination.

The bridle hitch provides excellent load stability when the load ia distributed equally among each sling leg. The load hook is directly over the center of gravity of the load, and the load is raised level. The use of bridle slings requires that the sling angles be carefully determined to ensure that the individual legs are not overloaded.

NOTE: It is wrong to conclude that a three- or four-leg bridle will safely lift a load equal to the safe load on one leg multiplied by the number of legs. This is because there is no way of knowing that each leg is carrying its share of the load.

With a four-legged bridle sling lifting a rigid load, it is possible for two of the legs to support practically the full load while the other two legs only balance it. COMSECOND/COMTHIRDNCB strongly recommend that the rated capacity for two-leg bridle slings listed in the COMSECOND/COMTHIRDNCBINST 11200.11 be used also as the safe working load for threeor four-leg bridle hitches.

When lifting heavy loads, you should ensure that the bottom of the sling legs is fastened to the load to prevent damage to the load. Many pieces of equipment have eyes fastened to them during the process of manufacture to aid in lifting. With some loads, though, fastening a hook to the eye on one end of each sling leg suffices to secure the sling to the load.

Use a protective pad when a fiber line or wire rope sling is exposed to sharp edges at the corners of a load. Pieces of wood or old rubber tires are fine for padding.