Dyneema dux on my folding tri

Discussion in 'Multihulls' started by rubyjeaan, Apr 16, 2012.

  1. rubyjeaan
    Joined: Feb 2012
    Posts: 59
    Likes: 2, Points: 0, Legacy Rep: 20
    Location: Klamath Falls, Oregon

    rubyjeaan Junior Member

    What would be the pro's & cons on using this on a folding tri? Looks like the way to go to me. Will be starting the building phase of the project soon. Will be using all Marine grade mahagony ply & cedar stringers, shooting for light.
    ..Michael..
     
  2. Stumble
    Joined: Oct 2008
    Posts: 1,913
    Likes: 73, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    It doesn't exist would be the first one... It's called Dynex dux.

    For standing rigging it is slightly larger diamater than wire, but at 1/7 the weight.

    The long term testing is still being done, so you can't expect more than 8 years

    Um.....
     
  3. cavalier mk2
    Joined: Mar 2010
    Posts: 2,132
    Likes: 56, Points: 48, Legacy Rep: 214
    Location: Pacific NW North America

    cavalier mk2 Senior Member

    I'd say go for it, I've been going that route on running backstays etc.... and can't find any problems, plus it isn't hard to splice.
     
  4. Stumble
    Joined: Oct 2008
    Posts: 1,913
    Likes: 73, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    I should have mentioned, get in touch with colligio marine. They are the ones spending the only on r&d for Dynex rigging, and have a number of specialty pieces that make the on a lot easier. Like solid 5:1 thimbles that won't crush under even extreme loads and the like. Plus they have a lot of other neat applications for the stuff.
     
  5. Samnz
    Joined: Nov 2008
    Posts: 235
    Likes: 4, Points: 0, Legacy Rep: 47
    Location: Auckland

    Samnz Senior Member

    iv got it on my sidestays. very stretchy. but nice and light and very strong.

    too stretchy for beam stays tho
     
  6. Stumble
    Joined: Oct 2008
    Posts: 1,913
    Likes: 73, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    Samnz,

    Dynex Dux has about the same stretch as wire when sized for load, if sized for creep (recommended) it actually has less than the wire you would typically find.
     
  7. Samnz
    Joined: Nov 2008
    Posts: 235
    Likes: 4, Points: 0, Legacy Rep: 47
    Location: Auckland

    Samnz Senior Member

    thats not what I have found on my boat. what kind of vessel/application are you using it on?
     
    Scuff likes this.
  8. Stumble
    Joined: Oct 2008
    Posts: 1,913
    Likes: 73, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    Tow boat hawsers, standing rigging, life lines, personally.

    Bridge sleuce gates, bridge temporary supports, commercial fishing nets - read about.


    There is a similar line called Amsteel blue which is the same chemical formula that some people have used instead of the Dux mistakenly, but it is not the same. The Dux is a whole different animal. It comes off the spool almost as stiff as wire, and needs different handling..
     
  9. teamvmg
    Joined: May 2008
    Posts: 124
    Likes: 4, Points: 0, Legacy Rep: 22
    Location: christchurch,uk

    teamvmg Senior Member

    that's not Dux then!
     
  10. Stumble
    Joined: Oct 2008
    Posts: 1,913
    Likes: 73, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    Just for compleatness sake, 7x19 316 stainless wire has an elongation at breaking strength of 4.5%. By comparison Dynex Dux has an elongation at breaking of 3.7%.

    Given that Dux is sized for creep, not MBL like wire, the possibility that someone is seeing actual stretch is next to impossible, assuming what you have is Dux, not something else.
     
  11. Samnz
    Joined: Nov 2008
    Posts: 235
    Likes: 4, Points: 0, Legacy Rep: 47
    Location: Auckland

    Samnz Senior Member

    comparing it to dyform 1/19. 7/19 is far to stretchy for standing rigging.

    if you can name a raceboat that uses dux for standing rigging id be very surprised, they all less stretchy material, i.e PBO, carbon etc

    If you pretension and ropecoat the spliced stay it helps a lot. some of the stretch is the splices bedding in. This is hard to do without a rather large loadcell/testbed. And getting someone to do it starts getting expensive
     
  12. Stumble
    Joined: Oct 2008
    Posts: 1,913
    Likes: 73, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    Sam,

    You are correct that ultra high budget boats are using either PBO or carbon rigging with an elongation at BL of around 2%, vs around 2.2% for Dyform, or 3.7 for Dynex. The difference is that because Dynex is specced for creep, not MBL, or stretch the loads relative to MBL for the Dynex are low enough that stretch just isn't observed.

    For instance, if a boat currently using 1/4" 1x19 304 stainless wire wanted to convert to Dynex...

    The current wire has a MBL of 8200lbs, or a SWL of 3280.
    Dynex is sized to keep creep to a minimum, so you need to keep the working load below 20% of MBL, so the proper size Dynex would be 16,400mbl. But that isn't made, so you have to go up to 9mm, with a MBL of 25,000lbs. This would give you creep elongation yearly of about .1inch, and a working load of about 10% of MBL of the line.

    At 10% MBL Dynex Dux stretches less than the wire specced for the same application.
     
  13. teamvmg
    Joined: May 2008
    Posts: 124
    Likes: 4, Points: 0, Legacy Rep: 22
    Location: christchurch,uk

    teamvmg Senior Member

    Where did you buy this stuff SAMNZ?
     
  14. upchurchmr
    Joined: Feb 2011
    Posts: 3,269
    Likes: 249, Points: 63, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    Rubyjean,

    I'm interested in the rope, but more in your folding tri. Have you posted any pictures or plans for your boat?

    Marc
     

  15. rubyjeaan
    Joined: Feb 2012
    Posts: 59
    Likes: 2, Points: 0, Legacy Rep: 20
    Location: Klamath Falls, Oregon

    rubyjeaan Junior Member

    Marc,

    Building a Horstman MT 26, but currently waiting on word from another boat ready to buy. Will post more as I figure out just what I'm going to do. Michael..
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.