Mooring is one of the most common of all maritime tasks, yet mooring operations are far from standard. To ensure safe mooring involving both new and existing LNG carriers and equipment, standards are currently being upgraded
The webinar Mooring solutions: MEG4. What have we learned so far? explored some of the key technical and operational issues that shipowners, operators and ports face in this evolving industry. Taking part were DSM Protective Materials technical and business development manager marine and offshore EMEA, Jac Spijkers and D Koronakis chief executive and managing director, Kostas Koronakis.
A key question for LNG terminal and vessel operators is: Which strategy provides the highest reliability in mooring operations? In a poll, 45% said good mooring line design by a reputable rope manufacturer including a service package and 33% preferred mooring lines with a built-in safety device (ie snapback). Only 13% thought replacing mooring lines at a predefined short interval was the most reliable strategy and 9% considered good mooring line design by a reputable rope manufacturer was the most reliable method. This poll illustrated the wide range of opinions on the subject.
Opening the webinar, Mr Spijkers highlighted one of the reasons for the implementation of MEG4 – the drive towards mooring line reliability and to reduce serious injury. He noted that almost one in four mooring line incidents results in a leg injury and one in seven incidents have resulted in fatalities – appalling statistics by any measure.
As an expert witness in court cases involving mooring lines made with Dyneema, he was very aware that the fibre itself was not the cause of the incidents. “In all these accidents, no one was killed. The Dyneema fibre was never to blame. The causes were: the way the rope had been handled in the past, the conduct of the mooring operation, and other activities not connected with the fibre,” he said.
Turning to MEG4, he noted that the MEG4 certificate varies in detail on the first page, and it is important the purchasers examine all the criteria. He warned that MEG4 is not a guarantee for fit for purpose mooring lines. “Why is that?” Mr Spijkers asked. “It is because MEG4 has no pass or fail criteria.”
While many understood this, there are also some fixed ideas on what the consumer sees as important in a mooring rope. In a survey: Which of these aspects is of most importance to you when deciding on mooring line performance? More than half (55%), listed tension fatigue as most important, followed by abrasion resistance.
Sustainability was the choice of 13%, with just 2% opting for temperature performance.
Mr Koronakis said the company is a pioneer in the use of modern fibres in mooring ropes and the emphasis has always been on safety. “Our proposal (for MEG4) was that there be ‘Danger Zone’ signs on the inside of doors (to the deck) visible before going out onto the deck,” he said. That has been adopted to some extent: in MEG4 the whole deck is considered a danger zone from snapback. With this is mind, D Koronakis has developed ropes with a reduced snapback effect. These have been developed in the largest test bench in southern Europe with a pulling capacity of 500 tonnes (a new 600-tonne facility is under development).
The lessons learned from the development of the snapback-resistant rope is that the tails are a crucial element in providing the elasticity. “If we have mooring lines that resist the parting of the tails and if we have tails that are snapback-free, then we can have a very safe mooring lines package,” said Mr Koronakis.
The use of fire wires or emergency towing-off pennants was one of the first questions asked during the webinar. These are not recommended by OCIMF in MEG4 but some terminals still insist on their use. The answer was that if the third-party requested fire wires, these can be made available.
One delegate was conducting mooring simulations and noted there is a difference between the technical specification of mooring lines in the LNG sector and the cruise sector due to the lack of universal practice and regulation. Also, the cruise industry is concerned with appearance and might have specified lines and tails with that as a criteria.
Mr Koronakis also highlighted a danger with cruise ship destinations, referring to the narrow-fronted quays at some cruise destinations and the general lack of discipline, with bystanders and passengers milling around the bollards. If a line was to part, “There is nowhere to hide,” he said. In these situations, a low snapback line would be a huge safety improvement.
While MEG4 is an improvement, some delegates questioned the feasibility of being able to test fatigue. Mr Spijkers noted that purchasing mooring ropes with a service package is one way to ensure this aspect of MEG4 could be met. Mr Koronakis pointed out that mooring lines made from modern fibres have a considerable life span, and it is a question of the strength in the tails that dictates the overall strength of the mooring package. “The best option is to have certified material and certified ropes,” said Mr Koronakis, “Then you know what you are dealing with.”
Terminals are known to demand different mooring ropes. Mr Spijkers said there needs to be a dialogue if demands are being made to switch out certified ropes. Mr Koronakis noted that terminals are not always correct when it comes to mooring and may have poorly designed hooks that can damage mooring ropes.
The strength of the mooring ropes on board a vessel was one of the areas discussed by delegates: the use of the ropes should be considered. Mr Koronakis agreed, and said the managers of the vessel should be aware of the terminals and ports and consider swells, gangways and other factors that impact on the usage and position of the mooring rope. There are also developments underway to indicate to crew the residual strength of a rope and warn of impending failure.
One delegate questioned if SIRE inspectors had enough expertise in mooring ropes to make assessments. Mr Spijkers said SIRE inspectors had guidelines, and these should be revisited if there is problem with inspections.
Mr Spijkers also commented that with ship-to-ship (STS) operations, as conducted in the LNG sector, close attention must be made to tails when there is a significant height variation. “Ship-to-ship is a totally different dynamic compared to ship-to-shore,” he said.
Mr Koronakis added that STS is a two-vessel scenario, and the tails are not chosen, but given by third-parties. In some cases the chokes and grommets are not compatible with the mooring ropes. He added that “STS is an issue that must be followed very carefully and twisted parts must not used with braided parts,” said Mr Koronakis. Regarding service life, Mr Koronakis said there are ways to check the strength of a mooring and a service agreement will cover this.
As a takeaway from the webinar, Mr Spijkers noted that as a fibre manufacturer, it is important that users buy their mooring ropes from a reputable manufacturer with a service package. He emphasised that the reliability of the rope was dependent on the fibres used.
Mr Koronakis said that as a rope manufacturer, it has used DSM Dyneema for 15 years and the quality of the fibre was evident. He said that if mooring operations are carried out properly and the mooring rope looked after, it could last 15 years or more without incident. “Not only are (Dyneema fibre) ropes light and easy to handle, but they are also cost effective, too,” he said. He added that if the correct tails are selected for the forces involved, it is a win-win.
The audience was asked to rate the most important part in the next update of MEG4. Mooring line reliability was key for 61%, followed by mooring line lifetime (21%) with 18% choosing sustainability aspects.
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