Our commitment to the Maritime Industry: Reliable data for mooring lines made with Dyneema®

A LinkedIn article previously published by Jorn Boesten, Segment Manager, Offshore Energy & Maritime

Nearing 2023, maritime vessels worldwide have now been using mooring lines made with Dyneema® fibers for more than 30 years. That’s quite an impressive track record!

Thousands of vessels rely on the performance of Dyneema® fibers in ropes made by the leading mooring rope manufacturers. Vessels carrying LNG, containers, crude oil, and dry bulk are moored with Dyneema®. And in ports, tugs increasingly rely on main towlines or pennants made with Dyneema® SK78 fiber.

We have always had a strong focus on making the best Dyneema® fiber for mooring lines.
In the early days, we focused on creating stronger fiber grades. From the early generation Dyneema® SK62 fiber tenacities (strength to weight ratio) were increased by 17% to reach Dyneema® SK75 and Dyneema® SK78, and onwards to Dyneema® SK99 (a further 24% increase), clearly “the world’s strongest fiberTM”. The increase in fiber strength is driven primarily by the requirements of the ballistic industry where increased strength is generally attributed with greater stopping power and consequently body armor with drastically reduced weight.

Yet how often do you expect your mooring line to stop a bullet?

There is indeed a clear difference between the performance requirements for instantaneously stopping a bullet and reliably mooring a LNG tanker time after time. That’s why choosing a mooring rope based solely on a minimum breaking strength isn’t as favourable as selecting a reliable mooring rope that will operate safely over an extensive period.  We made a conscious decision to provide fleet owners and captains with tangible data and relevant facts to aid them in their selection of mooring equipment.

Our maritime team realised that, in addition to meeting a minimum breaking strength requirement, mooring lines must perform under a multitude of conditions and are subject to abrasion, fatigue, and temperature fluctuations. These factors contribute to a mooring line’s ability to maintain a safe and reliable performance throughout the expected rope lifetime. In the field, vessel crews have learned how to use ropes and achieve lifetimes of 10+ years. This puts more pressure on the heart of the rope, the load bearing fiber, which will have to perform for the full lifespan.
Unfortunately, there are not commonly accepted test methods available for evaluating rope abrasion and fatigue performance.

Therefore, we invested in designing and constructing bespoke equipment to evaluate the abrasion and fatigue lifetime of ropes made with Dyneema® fibers. With this dedicated equipment we can test ropes close to their actual use conditions. From the test results we can derive how to further improve our Dyneema® fiber grades for enhanced mooring performance. To date, the results show that Dyneema® SK78 fiber has up to 3X higher fatigue performance and up to 4X better abrasion performance compared to generic high modulus polyethylene fibers.

The next step is being able to predict rope life as a function of its use. Based on our extensive test results we have created a fatigue performance model with core-equations certified by DNV. With the model we can reliably predict rope life by taking specific environmental conditions into account, thus increasing the safety of mooring operations.

Our engineering team is available to discuss your mooring requirements and assess the feasibility of mooring lines made with Dyneema® SK78 fiber for your specific mooring operation.

Are you interested in learning more? If so, please contact me directly or visit: https://www.dsm.com/dyneema/en_GB/applications/ropes-lines-slings-chains/mooring-and-tow-ropes/reliable-mooring.html

Jorn Boesten
Segment Manager, Offshore Energy & Maritime
Jorn.Boesten@dsm.com

 

Published on

15 November 2022

Tags

  • Ropes, Lines, Slings and Chains

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