April 16, 2013 at 7:28 pm #3110
1/4″ is plenty big. If it says amsteel and is gray and slippery..it is the marine version and most likely SK75. STRETCH IT hard before putting your thimbles in. It isn’t really stretch, it is ‘alignment’. It needs to be almost stiff before you can accurately measure it to fit. Because it is slippery..use long eye splices. I wove it up & down 3 times before inserting the core. Then I seized at the thimble. Do one end..then measure for the other.
You are talking ONLY the backstay, correct? It is not good enough for any shrouds, etc.April 17, 2013 at 4:50 am #3111
Has anyone worked with this stuff? http://www.lanex.cz/en/racing-line-d-f1
It seems to be pre-stretched, and has a surface finish to help counter wear. 1/4″ gives around 8300lbs load.April 17, 2013 at 3:14 pm #3112
I dont understand why all this discussion of different line. Amsteel, Robline,etc….
There are 3 basic types of line I have found that are universal to all manufacturers. Dyneema, Technora and Vectran. All three of these are the same from ANY manufacturer. Vectran is the ONLY line that has no creep. ALL lines stretch based upon their percentage of load vs breaking strength called “tensil strength”. The best way to make a comparison is to compare all three composites of the same size, say 1/4″ and given a specific length of a halyard say the jib(40′) and do a spread sheet to see the amount of stretch and what their load capacity is based upon a given load from their table. You will find Vectran has the highest strength, least weight and NO CREEP! I personally use Vectran for my main and jib and Dyneema for my wing halyards. I use the dyneema because it has a bit of shock absorbing charachteristic to it and stretch is not as much of a concern where with the main and jib zero stretch is crucial. Sutdy it for yourself and see…
There’s my 2 cents worth!!!April 17, 2013 at 3:37 pm #3113
There is a difference between amsteel grey and blue. Blue is sk75 dyneema, which is stronger with less creep than SK65 Grey. Other than that, yes, core materials are pretty much interchangeable between manufacturers. Braiding techniques will give greater or less diameter of the core vs cover material, and this is what gives different characteristics for the doublebraided lines. For single braids, there is negligible difference UNLESS you compare heat-set lines like DUX and traditional lines like Amsteel. There are big differences between these!
The cordage I used on Old School was vectran/dyneema blend for upwind halyards and double braid poly for the spins. I switched to a stripped straight dyneema for the genoa halyard last year because I found some cheap, and was having issues with the cover splitting on the vectran/dyneema blends (more of an issue with the cover than the core!)
This discussion is about backstays. I would NEVER use uncovered vectran as a backstay, as it is highly susceptible to UV degradation. If vectan is used in stripped halyards, it is advisable to sky the halyards if they are not going to be used for a while.April 17, 2013 at 3:58 pm #3114
I NEVER leave my halyards on the boat when its being stored. At the cost of replacement I prefer they last 4 years rather than 2. For the backstay I would use the Vectran WITH a cover. Btw, I “sky” my main halyard since I use a 2:1 purchase and that last few inches up there does get some UV exposure. My last main halyard lasted 3 years. Not bad! Also, has anyone calculated how much weight would be saved with a composite backstay? I figured roughly a 4lb weight saving over my rod backstay. I figure with my racing record I have to decide weather its feasable to squeeze a little weight savings along the whole backstay is worth the extra effort. In the overall scheme of things untill one is in the top three of their class its a futile effort but on the other hand the psychological advantage is priceless…..April 17, 2013 at 4:04 pm #3115
I did not weigh my rod when I took it off, but I doubt 4 pounds would be too far off the mark. 4 pounds @ average 18 feet off the waterline is huge! When I redid my rig a few years ago, I took everything out…conduit, wiring, wire halyards, etc, and replaced with modern stuff. I can’t tell you if it made a difference on the course, but I can say that it did not hurt!April 18, 2013 at 9:36 pm #3116
Just weighed my rod back stay, just the rod, not any of the block and tackle, about 32’long: 2.6lbs
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