The manufacturer's recommendations should be followed in determining the safe working loads of the various sizes and types of specific and identifiable hooks. All hooks for which no applicable manufacturer's recommendations are available should be tested to twice the intended safe working load before they are initially put into service.

Mousing is a technique often used to close the open section of a hook to keep slings, straps, and similar attachments from slipping off the hook, as shown in figure 6-58.

Hooks may be moused with rope yarn, seizing wire, or a shackle. When using rope yam or wire, make 8 to 10 wraps around both sides of the hook. To finish off, make several turns with the yarn or wire around the sides of the mousing, and then tie the ends securely.

Two types of shackles used in rigging are the anchor (fig. 6-59) and the chain (fig. 6-60). Both are available with screw pins or round pins.

Shackles should be used in the same configuration as they were manufactured. All pins must be straight and cotter pins must be used or all screw pins must be seated. When the original pin is lost or does not fit properly, do not use the shackle. Never replace the shackle pin with a bolt.

A shackle should never be pulled from the side. This causes the shackle to bend reducing its capacity tremendously. Always attach a screw pin shackle with the screw pin on the dead end of the rope. If placed on the running end, the movement of the rope may loosen t h e p i n .

Figure 6-58. - Mousing.

Figure 6-59. - Anchor shackles.

Figure 6-60. - Chain shackles.

Shackles are moused whenever there is a chance of the shackle pin working loose and coming out due to vibration. To mouse a shackle, simply take several turns with seizing wire through the eye of the pin and around the bow of the shackle. Refer to figure 6-58 for proper mousing.

REVIEW 3 QUESTIONS

Q1. What are the two types of brakes used on a jaw-clutch type winch?

Q2. What device is used on a winch to prevent crushing of the cable due to loose crossed coils and layers?

Q3. Wire rope is composed of what total number of parts?

Q4. What is the most common type of wire rope used by the NCF?

Q5. What is the recommended ratio of new oil to diesel for the lubrication of wire rope?