Choice of mooring rope makes a big difference

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“Be sure to choose the right mooring rope for your ship.” This is Thomas Linkruus talking, who has worked with ropes for 30 years.
The first question you should ask when it is time to buy new mooring ropes is: “What do I need for this particular ship?” The size of the ship, the capacity of the bollards and capstans, whether it has roller hawse-holes or fixed hawse-holes and how often and in what conditions it is moored are examples of factors that need to be taken into account. Another important question is the choice of material in the rope itself. Ordinary polyamide ropes (e.g. Atlas) or polypropylene ropes are relatively strong and easy to work with. They have some disadvantages, though; they have a large snap-back if they break and they are coarser and heavier than high-performance options such as Dyneema ropes. A new rope has a certain guaranteed breaking strength. With time the strength decreases due to the fibres ageing and external influences such as wear, UV, salt water, cold, paint and chemicals. Ropes are weakened by wear at the bend points around bollards, kings and hawse-holes.
“When a rope breaks it often happens at just those places where it is most worn,” says Thomas Linkruus.
He recommends a regular review of the ship’s ropes, but points out that there is a difference between normal wear and damage that may affect breaking strength. A rough surface does not reduce the rope’s capacity. Some manufacturers have recommendations for how rope should be handled, depending on wear or damage. Either replace the entire rope, or repair it by removing the damaged section and splice on a new eye. A correctly repaired rope is as strong as the initial rope, and the repair does not affect the breaking strength, he says. How often mooring ropes need to be replaced also depends on the material they are made from and how much they are used. According to Thomas Linkruus, basic ropes may need to be replaced every one to two years while mooring ropes in stronger materials can be used for many years. In recent years, mooring ropes in newer materials have become more widespread on the market. The new ropes are made of fibres such as Dyneema, for example.
“They are as strong as steel cable but weigh considerably less than conventional ropes. This makes them easier to handle and if they break, the snap-back is much less than many other ropes. The purchase price is above average, but on the other hand they last longer, so in certain applications and for certain types of ships it may be less expensive in the long term to invest in a Dyneema mooring rope.”
Thomas Linkruus’ tips for safer ropes
• Keep ropes dry and shielded from the sun when not in use. Factors such as UV, sea water, salt and cold can shorten the life of a rope.
• Avoid exposure to chemicals or paints. Certain types of fibres are strongly influenced by such exposure.
• Keep hawse-holes, kings and bollards in good condition. Rust and other rough surfaces cause increased wear on ropes. Paint hawse-holes and other surfaces that the rope touches with low-friction paint.
• Consider the choice of materials when new ropes are being purchased.
• Check ropes regularly on board for any signs of damage. Be particularly observant if you have ropes with an outer casing. The casing may provide some protection but at the same time it makes the inspection of strands almost impossible.
Linda Sundgren, text and photo

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