CEMP-E
EI 02G001
01 July 1997
Table 3-4. Advantages and disadvantages of fixed leaders.
Advantages
Disadvantages
Requires only a two-drum crane.
Heaviest and most expensive
of the three-leader types.
Superior accuracy in located leader in
More troublesome to assemble
vertical position and all batter positions.
and maintain.
Rigid control of leader during
positioning operation.
Compound batter angles can be
set and accurately maintained.
Boom can be lowered and leaders
folded under (for short haul over the
road and railroad travel) when crane
of adequate capacity is used. This
depends on the length of leader and
boom and the configurations of the crane.
Table 3-5. Advantages and disadvantages of swinging leaders.
Disadvantages
Advantages
Lightest, simplest, and least expensive.
Requires a 3-drum crane (one of leader,
one for hammer, one for pile) or a 2-
drum crane with lead hung on sling from
With stabbing points secured in the ground, this
boom point.
lead is free to rotate sufficiently to align hammer
with pile without precise alignment of crane with
Difficult control twist of leader if pile.
stabbing points are not secured into the
ground.
Leaders are generally 15 to 20 feet shorter than
the boom; crane can reach out further, assuming
Crane positioning is more difficult than
crane capacity is sufficient.
with any other type of leader. Operator
must rely on balance while center of
Can drive in a hole or ditch or over the edge of an
gravity continues to move.
excavation.
For long lead and boom requirement, the leader
weight can be supported on the ground while the
pile is lifted into place without excessively
increasing the working load.
3-27
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