Mooring Compensator Advisory
Rubber Snubbers and Stainless Mooring Springs act as excellent mooring compensators
Snubbers and Springs can be deployed on mooring and anchoring lines that require an extra amount of stretch to help deal with shock loads.
Some rubber snubbers can be retro fitted while some need to be threaded on to the rope before splicing the ends.
All rubber snubbers are a useful addition to a continuous mooring line.
Stainless Steel Springs are specifically designed to absorb fluctuating loads but they have one disadvantage - they normally require a two-part mooring line with the spring in between - Jimmy Green Marine recommend that stainless steel mooring springs are deployed on an extra mooring line so that there is always at least one continuous rope to take the load in event of spring failure.0
Rated Mooring Springs are a good investment when yachts are moored stern to because of the extra strain this places on the two stern lines. It is a common practice for these lines to be doubled up and it makes sense to fit the primary line with a rated stainless steel spring.
Mooring Compensators provide a valuable defence against shock loading, protecting ropes and deck fittings from damaging excess strain.
However, they are ultimately sacrificial and after a sustained period of hard work, they will deteriorate and eventually fail after satisfactorily fulfilling their function by taking the brunt of the elements.
The degree of snubber extension is dependent on the number of turns the rope makes around the central body of the snubber.
Longer extension = harder work for the compensator = more protection from snatch loads for the rope and deck fittings = reduced working life
In addition, each shock load results in a straightening of the mooring line which induces an extremely demanding twisting force on the snubber:
More turns = greater twisting force = reduced working life
Unimer and Forsheda generally suggest a maximum 3 turns but experience has shown that this is very demanding on the EPDM rubber when a yacht is bouncing around in a severe chop or swell.
Jimmy Green Marine recommend a more considered approach - evaluate what you wish to achieve at the outset and plan accordingly so that you are not disappointed by avoidable poor performance.
A reduction in the number of turns around the snubber to two or even one will make a big difference to the longevity of the compensator without putting undue strain on the warp or deck fittings.
Take the length of warp into account when assessing the forces that will be applied - a shorter line has less ability to stretch.
When a yacht is moored stern to:
The after warps will normally be required to withstand a much greater strain compared with a fore and aft berth alongside a pontoon
The after warps tend to be relatively short.
Rubber Snubbers are not designed to withstand permanent torsion loads so your mooring warp configuration can be set up for maximum control of the yacht's movement if desired but should still allow for a degree of flexing.
The satisfactory performance in terms of working life that a mooring compensator should reasonably be expected to fulfil is not one that is easy to answer.
One severe storm may well equate to several seasons of relatively benign pontoon visits.
If you have taken the Jimmy Green recommendations into account and your yacht has survived unscathed through some bad weather conditions, you may consider that replacing a snubber or two has been well worth the investment.
If you have any doubts about the performance of your compensators or your warps, please feedback your experience to the Jimmy Green Sales Team.
We will always endeavour to do our best on your behalf by making representation to the relevant Manufacturer/Distributor for suitable free of charge replacements where they are due.
We simply ask that you consider our recommendations before putting any replacements back into the same configuration without recognising the potential risks of overworking.