Wire rope is a versatile piece of equipment. In moorings, it can be used for motion control, stationkeeping, and vessel positioning, among other things. Beyond moorings, it can be used for other tasks such as guidance, tie down, hold back, lifting, and many more. Compared to chain, steel wire ropes have a higher strength to weight ratio, making them easier to install and lighter on the floating structure.
Steel wire ropes are mostly commonly constructed of many thin steel wires wound into strands, which are then wound around a central core into the final wire rope. The most commonly used configuration for this type of wire construction is six strand. The number of strands and wires in each strand (e.g. 6 × 19, 6 × 36, 6 × 61) are governed by required strength, fatigue and bending stiffness requirements for each application. During selection consideration, it is important to note that this construction can generate torque as tension increases.
Wire rope can also be constructed of only individual wires tightly spaced and wound without stranding, known as spiral strand. This construction commonly uses a sheath for protection since it is much more susceptible to damage. To eliminate torque, the rope construction (spiral strand, half locked and full locked coils) uses layers of wires (or bundles of wires) wound in opposing directions to obtain the torque balanced characteristics.
Wire rope has a lower fatigue life and is more sensitive to damage and corrosion compared to chain. As per DNV-OS-E304, wire rope segments in mooring lines are to be protected against corrosion attacks throughout the design life, either through coating of the strands or sheathing of the rope. Regular inspections are recommended throughout the design life to ensure the protection is intact and corrosion is within acceptable limits.
Termination connections also are available in various sizes to accommodate any size of mooring components.
All wire ropes and components are certified and approved for use offshore by facilities managers. InterMoor offers varying sizes and configurations for wire rope. All wire ropes have an independent wire rope core (IWRC) of the highest quality grade and meet all requirements necessary to perform in the offshore industry.