LNG Mooring Lines Made with Dyneema
Safer and Stronger than Steel
The introduction of new and larger vessels, Q-Flex and Q-Max, and new, often more exposed terminals becoming operational have changed mooring dynamics. The need to maintain workers’ safety at all times, whilst delivering maximum operational efficiency through lower costs and faster turnaround times remains unchanged.
DSM Dyneema, a close partner to the LNG industry, has done a study which concludes that these industry trends are changing the performance demands for LNG mooring lines.
In parallel to DSM Dyneema’s investigation, in 2011 members of the LNG community created a Users Group to further investigate HMPE mooring line failures which TTI (UK) was asked to facilitate. DSM Dyneema is part of the Users Group, while at the same time continuing its own investigation program.
DSM Dyneema has drawn up a number of recommendations to address these changing market demands and the 3% fail-rate of HMPE based LNG mooring lines. Key among these is the call for industry-wide standard guidelines for specifying and testing of LNG mooring lines – ensuring the right mooring line is commissioned for any particular working task and environment.
Easy to handle and safe
HMPE based mooring lines have been used in the LNG industry for over a decade and have proven their benefits over time in many different maritime applications such as oil tankers, containers, carriers, bulk cargo vessels, as well as Cruise liners, RoRo and Navy ships.
Ropes with Dyneema, used in 50% of LNG mooring lines, are as strong as steel wire ropes of the same diameter but at only one-seventh of the weight allowing for easier handling. Ropes with Dyneema are about 60% of the diameter and 30% of the weight of equally strong polyester or polyamide ropes.
Proven in practice
BW Shipping, part of the BW Group, one of the world’s leading maritime groups in the oil tanker, gas and offshore segments operating a fleet of 96 owned, part-owned or controlled vessels and FPSOs, has equipped a fleet of 11 tankers with mooring lines made with Dyneema made by Samson Rope Technologies and is seeing significant benefits.
A search for mooring lines that would be safer than conventional steel wire resulted in the selection of AmSteel Blue mooring lines with Dyneema. The lower weight of Dyneema based ropes means reduced deckhand injuries. Moreover, in the unlikely event of a rope failure, ropes with Dyneema show no snap-back like that shown by steel wire rope or polyester and nylon based ropes. Due to the nature of the fiber, effects like fish hooks or broken wire are not present thus preventing hand injuries.