Uses:
The main uses of the knot are (in decreasing order of usefulness):
1) secure a load in a way that can be easily undone when no longer
needed, but provides a block and tackle mechanism allowing a load to
be secured much more tightly than is otherwise possible. 2) shorten
a rope (though there are better ways to do this) and 3) bypass a
section of frayed rope - useful in poor economies where rope is
expensive.
Efficiency: 46%
Instructions:1) Pull a section of rope back and lay
it alongside the rope, so that the rope forms a Z pattern. 2) Flatten the Z so that there are 3 sections
of rope lying alongside each other, with two bights
where the rope reverses direction. 3) At each U-bend,
grasp the U-bend in one hand, thus holding two of the rope sections.
With the other hand form a small loop in the remaining section and
draw it over the bight so that the loop forms a half
hitch and stays there if the free end of the rope is pulled
taut. 4) Repeat step 3 at the other bight. 5)
Pull the knot tight.
The result is a flattened loop which is held at each end by a
half hitch. If the sides of the flattened loop are pulled away from
each other, the flattened loop ends pull out of the half hitches and
the knot falls apart, but if the free ends are pulled taut then the
knot remains secure.
Notes: This knot is extremely useful
for tying loads down such as on a trailer or truck. The knot has
three features which make it invaluable here:
it provides two loops, one at each end of the knot which can
be used to pass a rope through.
the knot remains secure under tension, the coarser the rope
the more secure it is
the knot falls apart easily when tension is removed.
The last of these attributes is invaluable. Other knots will bind
tightly and be almost impossible to undo if the knot has been placed
under great tension. This wastes time, rope and tempers when trying
to unload when a load has been delivered. The sheepshank by contrast
will fall apart immediately.
Typical use in tying down a load on a truck is:
start with one end of the rope tied in a clove hitch around a
rail. If the rope is reasonably coarse and this clove hitch is
held under tension then it will remain secure.
pass the rope over the load, around a rail on the other side
of the truck and back over the load to near the original clove
hitch
pull the rope reasonably taut and then form a sheepshank about
three feet from a rail on the side of the truck.
pass the free end of the rope around the rail on the side,
then back through the loop on the sheepshank nearest the rail,
then back to the rail.
pull hard on the free end of the rope to tighten it. The
structure of the knot provides a leveraging effect like a block
and tackle, so that considerable tension can be brought to bear
to secure the load.
when the tension is sufficient to secure the load but not
damage it, pass the rope around the rail and tie it in a series
of half hitches. If the rope is likely to bind and be difficult
to untie then use a loop of the free end, so that each half
hitch can be undone by pulling on the free end of the loop.
Instructions:
1) Pull a section of rope back and 