Right hand twisted ropes should be uncoiled from the inside in a counter-clockwise direction.
Braided ropes should be uncoiled by means of a turntable to avoid inducing twist.
Ropes delivered on a reel
Make sure that the reel is turning freely vertically or horizontally. Never take rope from a reel which is lying
on its side.
Installing a rope on a winch
Ropes should be installed on a flat (not grooved)
winch under tension with the wraps as tight as possible
between the flanges.
A minimum of 8 wraps should be maintained to avoid
slippage.
A maximum of 3 layers is ideal to avoid burying into
the lower layers.
For the installation of synthetic mooring lines, a split
drum winch (storage part and working part) is the
most appropriate.
Pulleys and sheaves should be well maintained and
rotate freely.
Grooves must be smooth and U-shaped. The groove
should be 10% greater than the rope diameter and the
groove depth at least half of the rope diameter.
Terminations
Never tie a knot in the rope. This will result in up to
50% loss of breaking strength. It is better to use
a splice. A well-executed splice will reduce the
strength by approximately 10%.
The recommended internal eye length is 5 times (with
a minimum of 3 times) the pin diameter and minimum
6 times the rope diameter. If it’s not possible to respect
these criteria the use of an appropriate thimble
is recommended.
Bending diameter
Also called D/d ratio where D is the
pin diameter and d the rope diameter.
Sometimes expressed as minimum
bending radius – half of the
bending diameter.
The static bending diameter (for
example around a shackle pin, bollard
etc.) should be 3 times the rope
diameter. This can be reduced to
a minimum of 2/1 for certain rope
types. Specially designed mooring
links can be used with a smaller
bending diameter.
The dynamic bending diameter (for
example sheaves, pulleys, capstans
etc.) may vary from 5/1 to 20/1, depending
on the type of rope.
Working load limit (WLL)
Should not exceed:
1/7 of the new rope breaking strength for lifting,
1/5 of the new rope breaking strength for mooring,
1/3 of the new rope breaking strength for pulling/
towing.
For certain applications a lower safety factor can be
certified by a standardization agency.
Shock loads should be avoided and never exceed
50% of the new rope breaking strength.
Overloading causes permanent damage and loss of
strength (fatigue).
In service
All rope bearing surfaces such as fairleads and
chocks should be smooth and free of damage and
rust. Sometimes it is advised to fit specially designed
chafe protections on vulnerable rope sections.
Avoid kinks in cabled ropes. The result is severe and
permanent strength loss.
Twists in braided ropes can cause uneven load distribution
between the right and left hand strands.
Never stand in the recoiling (snap-back) zone of a
rope under tension. In the case of rope failure, this
can result in severe injury or even death.
Storage
Rope should be stored off the ground in a clean, dry
area away from sunlight and hot surfaces.
Never drag rope over rough and dirty ground. Sand,
grit and rust infiltration can cause internal fibre damage.
Keep away from chemicals.
Before long term storage, rope used in seawater
must be washed to remove the salt crystals.
The best way to recoil and store rope is in a figure of 8.
