Why wire rope has no place in modern LNG mooring operations

Although steel wire rope is sometimes still purchased due to its lower initial cost, this approach may not factor in its overall lifecycle expense. Mr Fronzaglia said: “HMPE ropes have been shown to have a lower total cost of ownership over their lifetime.”

This is achieved not just through the rope’s extended service life, but through reduced maintenance requirements. Unlike steel, synthetic fibre does not require lubrication and causes less wear to associated deck equipment. Properly specified HMPE ropes can also remain in service for up to three times longer than steel alternatives, depending on environmental exposure and operating profile.

However, Mr Fronzaglia emphasised that not all HMPE ropes offer the same longevity. “As long as they are made from the right type of fibre, designed in the optimal way, and installed and maintained properly, they can outperform steel,” he said.

Performance disparities

Despite broad industry adoption of HMPE, the rapid expansion of this market has brought with it concerns about quality. The most prominent of these relates to generic, low-cost HMPE variants which offer reduced performance in critical areas such as abrasion resistance, fatigue life, and load-bearing consistency.

Framing this in practical terms, Mr Fronzaglia pointed out that “when vessel operators opt for a low-cost, generic fibre, they compromise the reliability of their mooring system — and the safety and efficiency of their operations.”

Some operators assume compliance with the OCIMF’s Mooring Equipment Guidelines (MEG4) is sufficient assurance of quality, but this is not necessarily the case. MEG4 requires that the rope be tested according to a prescribed methodology and verified by a third party, but it does not set pass/fail benchmarks for performance or durability.

“It does not include pass/fail criteria for fibre ropes,” Mr Fronzaglia confirmed. “MEG4 is only a minimum performance requirement and compliance means that the rope was tested and the numbers verified.”

In the absence of stricter oversight, the onus falls on shipowners, operators, and procurement officers to examine supplier documentation carefully.

One of the chief risks with lower-quality HMPE ropes is fatigue, which is impossible to detect during standard visual inspection. Over time, repeated cycles of tension and elevated temperature cause fibre degradation that may not present outward signs but can compromise the rope’s structural integrity.

“Unlike external damage, internal rope fatigue cannot be identified in a visual inspection,” Mr Fronzaglia noted. “That is why the choice of fibre ingredient is paramount.”

Even when high-grade fibre is used, the performance of the final rope product also depends on its construction. Some cost-cutting designs use less fibre and longer braid angles, which can meet Line Design Break Force (LDBF) requirements but compromise other vital attributes such as fatigue resistance and abrasion performance.

Operators also need to consider the service model offered by rope suppliers. Maintenance, inspection, and documentation support throughout the service life of the rope are essential to ensure that potential issues are caught early and addressed.

External pressures

The decline of steel is being accelerated by external pressures. The Panama Canal Authority, for instance, no longer permits wire ropes for new LNG passages. Elsewhere, some operators have embedded HMPE specifications into their fleet requirements.

Such decisions create a cascading effect: terminals and charterers increasingly expect vessels to arrive with compliant mooring configurations, and insurers may follow with new risk parameters.

With industry alignment forming around HMPE, steel is fast losing not only its economic logic but also its regulatory viability.

For LNG vessels operating at high ambient temperatures and often in exposed terminal environments, rope failure is not a hypothetical risk. The legacy of mooring line failures remains a stark reminder of what can happen when materials are poorly chosen or managed.

“Operators realise they need to prioritise long-term reliability,” said Mr Fronzaglia. “And that starts with the fibre inside the rope.”