guidance
Typical mooring arrangements
Mooring lines are often high tenacity (HT) ropes allowing for elastic elongation, such as those made of Polyamide (PA), Polyester (PES) or BiPo-/Polyolefine- Polyester mix, as these allow for the forces prevalent while moored to be safely absorbed while still maintaining a secure mooring. Using a tail helps to protect the main mooring line as the most part of the forces will be absorbed by it and it will therefore be the component subject to the most wear and tear – but can be easily (and inexpensively) replaced. This makes particular sense in larger vessels.
What to be aware of when switching from an HT to HM mooring system
As HM lines are thinner than their HT counterparts of the same strength, several things need to be kept in mind when converting to an HM-based mooring system from one that was based on HT lines. The safe working load (SWL) of the existing bollards and fairleads must be taken into consideration. Furthermore, the question of whether the dimensions of the onboard fairleads, bollards, capstan winches, etc. are still suitable with the new system will need to be addressed. With HM ropes being more compact than their HT counterparts and therefore generating higher contact pressures, it is also imperative to check and prepare all contact surfaces before installing a new system. In this way a smooth surface is provided to ensure the new lines won’t snag or chafe, thereby maximising their service life.
A short tale about tails
Tails are deployed as a sacrificial element in mooring systems and are connected to the main mooring line by means of a cow hitch, for example – or even better: with Gleistein’s GeoLink soft shackle. Tails take the brunt of shock loads to protect the more expensive main mooring lines from premature wear. Important for tails is that they boast a suitable level of elasticity, high abrasion resistance and possess good attributes for easy splicing. Furthermore, for the sake of easy handling, low weight and buoyancy are other useful characteristics. Tail lengths of either 11 or 22 metres have meanwhile established themselves as standard sizes on the market. According to OCIMF MEG4, the spliced MBL of tails should be 125–130% of the ship design MBL. SOLAS itself does not prescribe this ratio, but requires that the overall line design break forces remain within the defined range for the mooring system.
FLX Mooring System – premium performance with a clear economic edge
The FLX Mooring System combines an extremely durable, low-elongation main mooring line made with Dyneema® with a highly efficient tail that acts as a sacrificial element. The lightweight, compact main line lasts many times longer than a conventional mooring rope, while the tail absorbs the shock loads, wears like a traditional mooring line and only forms the last few metres of the ensemble – so it can be exchanged quickly and cost-effectively. In this way, the higher initial investment pays off after just a few replacement cycles, while the substantial savings in weight and space and the much easier handling are realised from