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I'm shopping for 3-strand dock lines. Question is which can withstand UV better, Polyester or Nylon ? How to tell by look and feel which is which ?
3-Strand Polyester or Nylon
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Neither will withstand UV better than the other though, dacron will withstand abrasion much better than nylon. Appearance is very similar. If I recall correctly, you can tell the difference by burning the ends of each. Nylon burns a different color. I'm sorry that I don't remember the details more clearly.
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The 3-strand I have will stiffen after some weeks under sun. I've seen big expensive boats using black 3-strand (3/4"-1") that stay subtle/soft throu its life. Impressive but I suppose expensive. I'm looking for "similar" but 1/2". Hopefully in affordable price range.
Nylon is generally preferred, as far as I can tell, for dock lines. I don't think there is a great deal of difference in strength, UV resistence, but nylon stretches more under a given load. This is advantageous to absorb shock. That said, one needs to take care when adjusting dock lines to accommodate the full range of tides (normal & wind) as well as wind conditions from any direction (including storms which can come on short notice). Next comes the question of double braided vs. three strand. I prefer double braided even though it is a bit more expensive, because it has less stretch than three strand...I'm trying to split the difference between polyester and nylon...some stretch for shock absorbing, not so much that I'm banging on the finger pier. Also, against those surprise storms that will damage your boat if a line chafes, I use two lines at the various locations. In my marina, it gets rough often and I see many people encounter some significant repair bills because of failed lines or improperly adjusted lines.
Also, double braid does not get as hard over time as does three strand, so handling on cleats is easier, and I think looks a bit better. With my lines doubled up as above, I generally don't worry about any storms less than 60-70 mph. When adjusting length of lines, keep in mind that stretch in a storm is going to be more than when you are just routine tying up, so allow for that. I find that handling 2 1/2 inch lines is easier than a single big line, and if I do get chafe damage, it usually has been on one of the two lines, so replacement of one small line is less than a big line. Since I leave the lines at the pier, the extra lines don't cause any additional deck clutter. Doubling lines is cheap insurance if you pier is in a rough location.
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Be aware that three-strand docklines are often better if you need to tie up to wooden pilings, as the double braids tend to bet picked apart by the splinters more than does three-strand laid lines.
Most docklines are usually nylon, mainly due to the stretch nylon has. Double braid nylon is a bit easier to handle, and doesn't have the tendency to hockle, like three-strand laid lines do. If you don't need to tie up to wooden pilings, get double braid nylon for your docklines.
Also, I highly recommend using woven cloth chafe protection, rather than hose, as one major cause of failure in docklines is from internal heat due to frictiion. Hose-type chafe guards prevent water from getting to the rope and soaking, lubricating and cooling it—woven fabric ones generally do not have this problem.
Most docklines are usually nylon, mainly due to the stretch nylon has. Double braid nylon is a bit easier to handle, and doesn't have the tendency to hockle, like three-strand laid lines do. If you don't need to tie up to wooden pilings, get double braid nylon for your docklines.
Also, I highly recommend using woven cloth chafe protection, rather than hose, as one major cause of failure in docklines is from internal heat due to frictiion. Hose-type chafe guards prevent water from getting to the rope and soaking, lubricating and cooling it—woven fabric ones generally do not have this problem.
For me the advantage of three strand nylon is that I can splice it myself much more easily. I agree with the comments above that the main reason to use nylon is that it stretches and is therefore more likely to absorb some os the shock of sudden loading better than the dacron.
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I second SD on not using hose for chafe protection. Our boat came with a 2 foot piece that I used for awhile and kept an eye on. (It wasn't the only line holding us.). The nylon line that I ran throught the hose actually melted in spots.
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I berth on a floating finger slip. Like others around my marina, my docklines are not very tight to allow some free movement. However in times of bad weather with strong waves, the surge caused the boat to shock-bang as the boat dance. I broke 2 Double Braid (WM-New England) and 2 DB with built-in rubber snubbers and broke a mounting screw for 1 of the cleats. Now I tighten all docklines to have as little slack (to prevent surging) and I use 2x 1/2" 3-strand for each cleats. Only thing is I don't know what material the 3-strand is made of. I do know in 3 months time it'll harden. Thanks for the feedback, I'll shop for 3-strand nylon. How can I if tell the 3-strand is nylon ?
Is it shiny and smooth when new or should I see some lint/fibre on the surface ?
Is it shiny and smooth when new or should I see some lint/fibre on the surface ?
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Splicing double braid nylon is not much more difficult that splicing 3 strand. Go get the appropriate fid from the local guy and give it a whirl. You find it easier than you thought.
Watch this video to see exactly how fast it can be done. I am sure he slowed down to allow for his commentary and explanations. Although he is doing a becket spllce, just make the eye larger for a mooring line.
YouTube DoubleBraid Becket Splice
Watch this video to see exactly how fast it can be done. I am sure he slowed down to allow for his commentary and explanations. Although he is doing a becket spllce, just make the eye larger for a mooring line.
YouTube DoubleBraid Becket Splice
Dock Lines
Nylon will stretch more, but usually it is the nylon lines that become harder as they shrink over time, whereas polyester lines tend to stay softer, and hold up to rubbing much better, as noted previously.
There was a good article on lines in general when I first joined Sailnet. Try the link here:
http://www.sailnet.com/forums/gear-maintenance-articles/19617-understanding-cordage.html
I prefer Polyester at least in fresh water, although I have both types on the boat.
Nylon will stretch more, but usually it is the nylon lines that become harder as they shrink over time, whereas polyester lines tend to stay softer, and hold up to rubbing much better, as noted previously.
There was a good article on lines in general when I first joined Sailnet. Try the link here:
http://www.sailnet.com/forums/gear-maintenance-articles/19617-understanding-cordage.html
I prefer Polyester at least in fresh water, although I have both types on the boat.
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Patrick Rea, many thanks for Youtube video. I've the fid from Samson but just don't know how to start. This video is very helpful indeed.
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Pdean, thanks for the link. Good info.
Trantor,
Assuming that your lines were relatively new, you should not have chafed four lines in a short period of time. As you know, chafing is almost always the mode of line failure and something appears to be accelerating this in your case. While double braid may chafe a little faster than 3 strand, either should work well in normal docking, even in rough harbors. It seems you may need the extra shock absorbing of the more stretchy 3 strand over the characteristics of double braid, but if you went through four lines in short order on double braid, you're likely to have some problems with 3 strand. Examine exactly where the lines failed. If there is a rough spot or sharp edge, even a very small one, it will cut through a line that is flexing in a short time. A smooth round head stanchion bolt did the job for me once. Are you using proper chafing gear at the contact points?...not plastic hose. How are the other boats of comparable size and exposure to the waves in your marina handling the situation. IF something is working for them, it'll probably work for you. Did the loose cleat bolt figure in on the chafing by contacting the line...why did it become loose? Any boat supply store will know what kind of line that they are selling, so you can go there and see what the manufacturer has marked on the reel of line or on the boxes for the line. Good luck.
Assuming that your lines were relatively new, you should not have chafed four lines in a short period of time. As you know, chafing is almost always the mode of line failure and something appears to be accelerating this in your case. While double braid may chafe a little faster than 3 strand, either should work well in normal docking, even in rough harbors. It seems you may need the extra shock absorbing of the more stretchy 3 strand over the characteristics of double braid, but if you went through four lines in short order on double braid, you're likely to have some problems with 3 strand. Examine exactly where the lines failed. If there is a rough spot or sharp edge, even a very small one, it will cut through a line that is flexing in a short time. A smooth round head stanchion bolt did the job for me once. Are you using proper chafing gear at the contact points?...not plastic hose. How are the other boats of comparable size and exposure to the waves in your marina handling the situation. IF something is working for them, it'll probably work for you. Did the loose cleat bolt figure in on the chafing by contacting the line...why did it become loose? Any boat supply store will know what kind of line that they are selling, so you can go there and see what the manufacturer has marked on the reel of line or on the boxes for the line. Good luck.
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NCC320, my lines broke at near mid point betw dock cleats and boat cleats. These instances it definitely shocking load that snap the lines although I do see chafing betw ropes on the boat cleats but that are just sign and not too serious ...for now. I'm not the only one having broken lines. The marina mechanic advised that I tigthen all docklines to prevent shocking-loads. He said that way, my boat will move up and down with the berth and with very little side movement to stress the lines. I'm doing that now.
Trantor,
Yours is indeed a puzzling situation. Three strand and keeping the slack to a minimum in the floating marina should help. Three strand 1/2 inch Nylon generally has a breaking strength of ~5,700 lbs. or greater. Assuming a safe working load of say10%, two lines on a cleat should handle 1140 lbs. of tensile force. That's a lot of pull unless you are in hurricane conditions. If the lines are breaking in the middle, then, if it were my boat I'd go to larger lines...maybe 2 x 3/4 inch. There is some point where the line size will be sufficient to prevent line being pulled apart in the middle. Just a thought....are you sure that the lines are either 100% polyester or 100% nylon? Recently, I was in one of the building supply stores and I saw something I have never seen before....a mixture of polypropylene and polyester. The line was three strand and white. Also, in our marina, I recently saw a good size motor cruiser tied up with polypropylene (this one was blue and white, I've seen it in stores, so I know that's what it was). Polypropylene generally doesn't have good stretch characteristics and looses its strength quickly in sunlight.
Yours is indeed a puzzling situation. Three strand and keeping the slack to a minimum in the floating marina should help. Three strand 1/2 inch Nylon generally has a breaking strength of ~5,700 lbs. or greater. Assuming a safe working load of say10%, two lines on a cleat should handle 1140 lbs. of tensile force. That's a lot of pull unless you are in hurricane conditions. If the lines are breaking in the middle, then, if it were my boat I'd go to larger lines...maybe 2 x 3/4 inch. There is some point where the line size will be sufficient to prevent line being pulled apart in the middle. Just a thought....are you sure that the lines are either 100% polyester or 100% nylon? Recently, I was in one of the building supply stores and I saw something I have never seen before....a mixture of polypropylene and polyester. The line was three strand and white. Also, in our marina, I recently saw a good size motor cruiser tied up with polypropylene (this one was blue and white, I've seen it in stores, so I know that's what it was). Polypropylene generally doesn't have good stretch characteristics and looses its strength quickly in sunlight.
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trantor,
Dacron is of virtually the same strength as nylon.
Nylon stretches 40% over original length at parting. Dacron, or polyester, about 70% of nylon. In my book, that's plenty enough elongation, especially if you're trying to keep your boat from horsing around. Another words, given the same strain on a properly sized mooring line dacron will stretch about 30% less than nylon under the same load. (People often mistake stretch for strength.) Dacron is worth it just for it's superior abrasion resistance. I'd use a laid line versus a braided one for the same reason; superior abrasion resistance.
Dacron is of virtually the same strength as nylon.
Nylon stretches 40% over original length at parting. Dacron, or polyester, about 70% of nylon. In my book, that's plenty enough elongation, especially if you're trying to keep your boat from horsing around. Another words, given the same strain on a properly sized mooring line dacron will stretch about 30% less than nylon under the same load. (People often mistake stretch for strength.) Dacron is worth it just for it's superior abrasion resistance. I'd use a laid line versus a braided one for the same reason; superior abrasion resistance.
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ok how does dacron rope looks like ? I don't think rope suppliers here is knows anything beyond nylon and polyester.
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Dacron is a name-brand of polyester, like Lexan is a name-brand of polycarbonate.
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