Our sailboat has ridden out four tropical storms/hurricanes in the Tampa area. We were double and triple tied up with 3 ply nylon lines and thankfully suffered no major damage, but after four of these storms, our docklines have all been stretched. Am I correct in assuming that as a result, that it's time to toss these lines out (or store them for emergencies) and get new lines, or can they still be trusted? Ken Parrot
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The price of new lines, or the price of boat--
repairs or replacement. Replace the lines and thank the Gods that you had the option. Glad to hear someone made it through. Tom s/v GAIA
repairs or replacement. Replace the lines and thank the Gods that you had the option. Glad to hear someone made it through. Tom s/v GAIA
- Jan 22, 2008
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Docklines
Ken We can't see them. We don't know what condition they were in to begin with. Only you can tell if they look and feel OK. You can always use them as backups. Glad all is well. Stu
Ken We can't see them. We don't know what condition they were in to begin with. Only you can tell if they look and feel OK. You can always use them as backups. Glad all is well. Stu
A rope expert?
I would guess that if nylon ropes are only stretched with no frayed sections, or broken fibers, then their breaking strength is probably still the same, but their shock absorbing spring is reduced. Because the spring can help to decelerate the boat as it oscillates in the wind and waves, a sprung line might increase the strain on your fittings by pulling the boat up short more often. I would be considering the alternatives of one new set of lines (keeping the others to double or triple the first in a storm) versus replacing them all. But I think this problem is interesting, common, and expensive enough to call one of the reputable rope companies, and ask for their expert advice. If you do, please let us know what they say. David Lady Lillie
I would guess that if nylon ropes are only stretched with no frayed sections, or broken fibers, then their breaking strength is probably still the same, but their shock absorbing spring is reduced. Because the spring can help to decelerate the boat as it oscillates in the wind and waves, a sprung line might increase the strain on your fittings by pulling the boat up short more often. I would be considering the alternatives of one new set of lines (keeping the others to double or triple the first in a storm) versus replacing them all. But I think this problem is interesting, common, and expensive enough to call one of the reputable rope companies, and ask for their expert advice. If you do, please let us know what they say. David Lady Lillie
What's the issue?
Replace the dock lines if there is ANY question. The cost is not that much (relatively speaking) and in this case, its better to err on the side of safety. What is the deductible on your insurance? Would the insurance company even cover damage if they discover you were using defective / worn dock lines?
Replace the dock lines if there is ANY question. The cost is not that much (relatively speaking) and in this case, its better to err on the side of safety. What is the deductible on your insurance? Would the insurance company even cover damage if they discover you were using defective / worn dock lines?
Absolutely!!!!
Studies done on nylon dock lines after Hurricane Andrew conclusively established that the stretching caused by frequent and repeated surging during storms results in high internal heat generated by the friction of the fibers in twisted lines. This heat causes a degradation of the strength of the internal strands. The external strands are better able to dissipate the heat quickly and are relatively unaffected. The result is that the damage is hidden from a surface inspection. The conclusions of those conducting the study(Boat US? I can't recall) was to inspect the inside strands of all twisted ply nylon dock after a major storm and after a series of gale force storms by unlaying the strands and to consider replacement as cheap insurance. They also recommended braided lines as the construction of these lines produced less friction under stretch which produced less heat and resulted in less degradation.
Studies done on nylon dock lines after Hurricane Andrew conclusively established that the stretching caused by frequent and repeated surging during storms results in high internal heat generated by the friction of the fibers in twisted lines. This heat causes a degradation of the strength of the internal strands. The external strands are better able to dissipate the heat quickly and are relatively unaffected. The result is that the damage is hidden from a surface inspection. The conclusions of those conducting the study(Boat US? I can't recall) was to inspect the inside strands of all twisted ply nylon dock after a major storm and after a series of gale force storms by unlaying the strands and to consider replacement as cheap insurance. They also recommended braided lines as the construction of these lines produced less friction under stretch which produced less heat and resulted in less degradation.
Dock Lines
A common mistake in buying dock lines is to get ones that are too large in diameter. The larger you get, the less stretch and shock absorption. I would get new ones; the same diameter you presently have; possibly longer, if you think it may be helpful. Good dock lines are cheap insurance.
A common mistake in buying dock lines is to get ones that are too large in diameter. The larger you get, the less stretch and shock absorption. I would get new ones; the same diameter you presently have; possibly longer, if you think it may be helpful. Good dock lines are cheap insurance.
West Marine rigging shop
was sent some large lines (used for Isabel) to be spliced afterwards, the shop refused the job because of internal strain and distortion of fibers. They looked okay on the outside.
was sent some large lines (used for Isabel) to be spliced afterwards, the shop refused the job because of internal strain and distortion of fibers. They looked okay on the outside.
Do you replace your tires after you hit a bump???
I often worry about that as I have a truck with four wheel drive. Running around in the woods hitting rocks and logs and then going down the interstate at 80mph....suicidal??? I am sure that a tire store would recommend replacement!!! Use common sense. I check the tires after a bad bump or trip off road. If there is obvious damage I replace the tire. Same thing with the ropes. If they are old or frayed with obvious damage replace them... But if they are fairly new and appear in good condition they are probably alright. But while you are in the replacement mode you might want to replace or at least rebed the cleats!!! There might be hidden cracks and the fiberglass might be getting ready to fail. The standing rigging took a lot of abuse might want to replace it also. Hmmm maybe the tie rods on my truck need replacing, and I did drive through a creek maybe it's time to replace the brakes and wheel bearings....
I often worry about that as I have a truck with four wheel drive. Running around in the woods hitting rocks and logs and then going down the interstate at 80mph....suicidal??? I am sure that a tire store would recommend replacement!!! Use common sense. I check the tires after a bad bump or trip off road. If there is obvious damage I replace the tire. Same thing with the ropes. If they are old or frayed with obvious damage replace them... But if they are fairly new and appear in good condition they are probably alright. But while you are in the replacement mode you might want to replace or at least rebed the cleats!!! There might be hidden cracks and the fiberglass might be getting ready to fail. The standing rigging took a lot of abuse might want to replace it also. Hmmm maybe the tie rods on my truck need replacing, and I did drive through a creek maybe it's time to replace the brakes and wheel bearings....
I'm glad you agree
about replacing them if there is obvious damage, because the author states that the lines are indeed stretched after four hurricanes and presumably have far exceeded their safe working loads to the point of no return. At the very least they have lost much of their desired elasticity, and are hardly an extravagant precaution for hurricane #5. And after four hurricanes I think I would (call me overcautious) inspect the standing rigging again.
about replacing them if there is obvious damage, because the author states that the lines are indeed stretched after four hurricanes and presumably have far exceeded their safe working loads to the point of no return. At the very least they have lost much of their desired elasticity, and are hardly an extravagant precaution for hurricane #5. And after four hurricanes I think I would (call me overcautious) inspect the standing rigging again.
the test
I used to run a mountaineering school in Colorado, and we'd throw away about 1,200 feet of climbing rope every summer. The way we determined whether a rope was still usable was quite simple. After it had sustained a fall, we measured it. If it was stretched, it was condemned. The theory here was thatit was better to throw a line away one fall too early than one fall too late.
I used to run a mountaineering school in Colorado, and we'd throw away about 1,200 feet of climbing rope every summer. The way we determined whether a rope was still usable was quite simple. After it had sustained a fall, we measured it. If it was stretched, it was condemned. The theory here was thatit was better to throw a line away one fall too early than one fall too late.
Toss them
I agree with John. They have suffered enough abuse. Their ability to disperse shock load has probably been greatly reduced, something you cannot see with the naked eye. Relegate them to something simple like fender lines or to tie up the dog. Whatever you do, don't use them as emergency lines. As you pointed out they have put in their emergency use and would not be safe in the future.
I agree with John. They have suffered enough abuse. Their ability to disperse shock load has probably been greatly reduced, something you cannot see with the naked eye. Relegate them to something simple like fender lines or to tie up the dog. Whatever you do, don't use them as emergency lines. As you pointed out they have put in their emergency use and would not be safe in the future.
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