How to check your mooring lines

When the new mooring lines are taken out of the delivery package, take great care to layout the mooring lines as straight as possible. It is advised to lay the mooring lines out as long as possible to identify if there are any induced twists in the rope, caused by uncoiling and handling of the rope. Each completed twist or turn in the rope reduces its break load by 7%. By avoiding and removing this you give the dock line the best possible start.

Take care when running out the line not to drag the line over rough or heavily contaminated surfaces. Dirt and grit accumulated in the rope can act like sandpaper and accelerate wear.

Check your lines

When you check your mooring lines regularly, big problems can be avoided, small abrasion damaged spots can of little impact on the lines performance if spotted in time. We offer a free mooring line checklist which can help you identify problems and give you a step by step guide for the most common problems.

Chafe and abrasion damage

With vessels getting larger and larger, loads placed on mooring lines get even more higher. The friction this creates on fair-leads or eye-splices can easily cut through lines or melt the cover and core.

The best defense is Chafe-Protection on the problem areas, when proper chafe protection is placed when the lines are new and closely monitored a long service life of the main lines can be guaranteed.

Chafe damage on cover

A very common problem, and most often often found in high abrasive or friction areas.

A little fussing or couple of abrasion worn strands is nothing to worry about. Take care by installing proper chafe protection to protect the line from further damage caused by abrasion and friction. Monitor the line to make sure it doesn’t get worse. When the cover starts breaking up great care should be taken as break loads of double braided lines can dramatically drop if the cover breaks.


Cut strands and visible core

Also very common and often a result of not taking proper action when the lines start showing damage.

If the cover has obvious broken strand or if the core in a double braided line becomes visible it is time for immediate line retirement. A double braided polyester or nylon line need both the cover and core intact to perform. Broken covers reduce the break load by at least 50%.

To prevent this make sure to install chafe-protection in fairleads, on eye-splices or other high friction areas. When new lines are first taken into service.

Completely broken cover

Very obvious damage where the cover has parted. This type of failure should not be overlooked, the core would still be able to handle 50% of the normal break load but since the cover has broken there is nothing to hold on to.

Lines showing this type of damage should be discarded and retired immediately.

Salt water

When a mooring line has been submerged in salt water salt concentrations can begin to form. After the mooring rope has dried do not immediately take the rope back into service as salt is very sharp and intensifies yarn on yarn abrasion. It is best to thoroughly wash the salt spots away with fresh water before the rope is taken into service.

Rust spots

Rope to rust contact should be avoided, especially panama leads should be well maintained. If the rope comes in extensive contact with rust or heavy corroded surfaces the break load of a Nylon rope can drop by as much as 40% in just one month of use. If a Nylon rope shows rust spots it should be removed from service as this can be an indication of big internal problems.

UV Exposure

The service life of marine ropes are not as easy to determine. If storage conditions are ideal, the rope in theory does only age very minimal. If ropes are placed under constant tension, in a very hot or cold climate, or suffer extensive from solar radiation their lifetime can be significantly reduced. Nylon or other synthetic mooring lines which are placed in constant UV radiation can have their break loads impacted in just 3 months.

When you store your ropes, take care to keep them out of the sun or hot environments as much as possible.