Technical information

Physical properties

Extension and elasticity

The overall extension of a rope is made up from several components.

Permanent extension
Is not recoverable. It will occur when a new rope is first used.
A result of the individual rope-fibre components “bedding in” to their preferred position.

Visco-elastic extension
Is only recoverable with time after the release of the rope.

Elastic extension
Is immediately recoverable upon the release of the rope.

Components of rope extension

Tensile strength

Is determined by testing new ropes according to EN ISO quality standards.
The strength of spliced ropes is reduced by 10%.
Nylon (polyamide) rope loses 10% of its strength when wet.

Mass

Is determined by weighing a rope sample to EN ISO quality standards.

Comparison of some mooring ropes with breaking load of ±72t

+ Fair ++ Good +++ Excellent


From this comparison one can conclude the following:

HSCP
An improved version of polypropylene - good lifetime due to good abrasion resistance - more cost-effective than polypropylene (smaller size for equal breaking load) - floats

Polyproylene
Most common mooring rope - floats - inexpensive - big volume for high breaking load - limited lifetime - sensitive to abrasion

Polydacron 2nd
Good price/strength/weight ratio - good abrasion resistance - floats

Nylon 8-strand
Good strength/weight ratio - high elongation is an advantage for certain applications (springs/pennants); sometimes a handicap in view of safety - rather expensive - sinks

Nylon double braided
The compact design offers size for size greater strength than 8-strand construction - excellent for use on tension winches/capstans - excellent abrasion resistance - suitable for various shock load applications

Superwinchline polyester
Perfect for use on self-tensioning winches - very good abrasion resistance - compact construction

Steelite 12 Xtra
Size for size Steelite 12 Xtra offers the same strength as steel wire rope but is extremely lightweight and easy to handle - the elongation is also comparable to steel wire rope - Steelite 12 Xtra is not sensitive to corrosion (apply for specifi c cases) - floats - expensive - need adapted equipment (as for all synthetic ropes)

Diverse

• Intertanko/OCIMF regulations dissuade the use of 100% polypropylene ropes for mooring of tankers. HSCP / polydacron / polymix / polyester / nylon /Steelite are accepted.
• The consequence of using rope with high breaking load and minimum diameter is that the rope is more sensitive to abrasion due to a smaller contact area.
• The strength of spliced rope is generally reduced by 10%.
• The strength of wet nylon rope is reduced by 10%. The original breaking strength will recover when the rope is dry again.
• A general rule for the use of springs in combination with steel wire or Steelite mooring ropes is that the spring MBL must be 25% higher than the mooring rope MBL (37% for nylon in view of water absorption).