Quote:
Originally Posted by Mark Johnson
Can any of you guys with years of experience using synthetic rigging, fill me in on the following?
The comparison that I would like to see between Dux and 316 SS wire, is @ 18 or 20 years old. Of the countless thousands of boats in our area, (Eastern NC), there has only been one dismasting in the last 5 years to my knowledge, and it was a new racing boat under extreem conditions. If one removes from the conversation the < 5% who are cruising all over the world, or live full time in the tropics... The other 95% around here spend winters in the Bahamas, are daysailors & local cruisers, or make a couple of one or two year Caribbean cruises... still spending the majority of their years in our moderate lattitudes, and brackish water. Of this 95% of cruisers, almost all go over 18 or 20 years before changing out their rigging, some even go to 30 years, (admittedly at their own risk)! Has your accelerated UV testing made a compairison to wire at this 18 + year life span, under the above circumstances?
Another point I am curious about... I have switched to some DUX synthetic rigging 6 months back, they are for my running backstays, and DUX seems like a perfect application here. I normally leave them "made up" and fairly snug, to use as a handhold when boarding the boat. When using the staysail, I will put 4 more turns on the "quick adjust" handle turnbuckles, but so far, haven't given them the acid test.
I go to the boat daily, and have noticed that @ 75 degrees F, the runners are quite snug, but @ 40 degrees F, perhaps that same morning, they hang completely limp. Since solid materials expand when heated, and contract when cooled, it can't be that the DUX has gotten longer on a cool morning. I assume that the metal mast has contracted at a rate vastly higher than the DUX, creating loose runners in the morning. Presumably with wooden or composite spars this is less of a problem,. My wire rigging has never done this "changing tune with temperature", and I imagine that it's because the wire expands and contracts at a rate somewhat similar to the metal mast.
With aluminum mast that are long & skinny, (like mine), and dependant on consistant shroud tension to keep the mast in column, wouldn't this become a problem if I tune the rig in the summer, then go sailing on a cool fall day? Has anyone else noticed this characteristic? I have done a LOT of reading on synthetics, and have yet to see this subject brought up...
Best regards, Mark
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Hi Mark, please see the FAQ's on our site about Colligo Dux Rigging.
We now have enough data to say 5-8 years for a replacement interval of Dynex Dux in the Tropics. This data is still coming in and we are watching it closely. As an engineer and a sailor, I can tell you that I wouldn't feel comfortable going offshore with a stainless rig on a saltwater boat over 10 years old unless, possibly, I knew it was washed with freshwater almost daily. Maybe with stayloks that were completely inspected, certainly not swage fittings. To my knowledge, most of the wire rope manufacturers recommend 8-10 years as a replacement interval for stainless wire. I am sure Brion has a valuable opinion here.
On the tuning, 2 things.
1. The coeficient of thermal expansion (COTE) of dyneema is less than that of aluminum, so you get a difference in expansion rates in the temperature ranges you see on a boat. If you do some calcs on an aluminum mast you would probably be surprised on how much growth you can expect. The COTE of Steel is also different than aluminum but not as much and is usually masked by the higher amount of pretension with turnbuckles.
If you use turnbuckles with some amount of pretension you will usually not see the loosening of the shrouds, if you use lashings than you will probably notice it as the amount of pretension will probably not be enough to cover the thermal expansion of the mast. Some of our customers have noticed this and after tensioning in colder weather they have enough pretension to not see the issue again. If you have a rig that requires more pretension (or better control of tension) we recommend using turnbuckles for pre-tensioning.
We also now have Loos gauge calibrations for several sizes of Dux to help with setting the tension.
You will have a little more maintenance with Colligo Dux, especially with lashing tensioners, but you should expect this as you need to inspect for chafe more (than steel) also. All synthetics, PBO, Carbon, Dyneema, Aramids, etc put more responsiblity in the hands of the sailor as there are alot of unknowns as none of them have been used as long as Steel.
You will not find a synthetic rig that will give you the same amount of confidence as steel for probably about another 100 years or so.
John Franta, Colligo Marine