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
manufacturers 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
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 6-59.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
REVIEW 3 QUESTIONS
What are the two types of brakes used on a jaw-
clutch type winch?
What device is used on a winch to prevent
crushing of the cable due to loose crossed coils
Wire rope is composed of what total number of
What is the most common type of wire rope used
by the NCF?
What is the recommended ratio of new oil to
diesel for the lubrication of wire rope?