Dynema Dux

[sailaway78]

It is coming near time to replace the standing rigging on my boat. Or already is time. I have been researching the Dynema Dux and everything I find seems to be at least as good as, and in many cases better than 1 x 19 stainless. Of particular interest is the ability to splice, replace, repair much easier than with stainless wire. Would certainly be much easier to cut loose in case of a dismasting. The need to carry spares would require much less space, and I think would be much simpler. Initial cost apprears to be close to the same, and any future replacement, or repairs much less expensive. Strength is equal or greater. Stretch is claimed to be less. Rigging is pretty simple. Does anyone have any experience with this stuff. I know there will be lots of opinions, so lets hear them too. Not in a great big rush, but replacement is in my near future.

 

[Roger Long]

See if you can get them to guarantee you the same life and UV resistance as stainless

 

[Ed Schenck]

What about the forestay? Can you "wrap" a furler around it? That would be my main issue I think. Sounds great otherwise.

 

[sailaway78]

To answer

First off, I have not seen, nor been able to find, an answer to the UV question. There are a couple of reports of no chafe, or other problems, but nothing specifically relating to the UV question. However, UV does not appear to be a major problem with halyards and sheets, so my primary answer is that it will be OK. I don't know that this stuff has been available long enough for anyone to have a good feel for it's longevity. As for the forestay, I replaced the forestay last summer, so would not change it, and do not think I would want a roller furler on a non metallic forestay.

 

[kloudie1]

Sounds liike a good idea to be able to reduce so much weight aloft.. but my concerns are for chafe and UV sensitivity.. (as both Roger and Ed have already noted)
If one were to forward think, it may be that the Dynema price may come down in the future so that it can be replaced for less.. reusing the end terminals a couple of times.. Lots of other benefits like you noted, Phil.. carrying spares gets to be really easy. It will be interesting to see how the stuf works out because more and more folks are thinking of going that way.

 

[BobM]

I think Roger is on track. Although riggers suggest you replace your SS rigging every 10 years the reality of it is that there is plenty of 30 year old rigging out there. That is a lot of UV damage for any line to take. They are "predicting" a life of 5 years and anticipating much longer, but apparently lack hard UV data (see their FAQ's, pdf link about mid page). It is actually called Dynex Dux, which is made using Dyneema fibers.

http://www.colligomarine.com/Colligo-Synthetic-Systems/Dynex-Dux.htm

My 2C? It is my understanding that most SS rigging failures occur at the base due to water intrusion and corrosion in the swages. With the advent of easy to use, albeit somewhat expensive mechanical swage fittings I don't see a significant advantage in taking such a risk given the dearth of data.

For emergency use perhaps you could carry some mechanical fittings with extra long studs. I don't get it myself. They say that they have a boat in Mexico getting real time data. That is ridiculous. There are no doubt many standard tests for UV exposure that could be applied. I couldn't find any hard data either. Perhaps you could contact DSM, who makes the Dyneema fibers.

To me it looks like you could end up replacing your standing rigging every 10 years versus perhaps every 10-30 years for stainless for about the same cost. It could end up being a negative when you sell your boat rather than the positive new SS standing rigging would be.

Also, I wouldn't bet that the stuff is easier to work with or even cut. Dyneema fibers can stop bullets! Sounds like you have done your homework though and you know about this issue. Didn't we have a post like this in the past where cutting the line turned out to be a major issue?

I'd be interested in trying stuff like this for life lines first. SS rigging isn't "broke" in my opinion, but the whole concept of white plastic coating on SS lifelines sucks. I'd replace with thicker uncoated SS wire, but the number of swages involved still makes it pretty expensive. Be nice to just run some line and tie some knots.

 

[tommays]

Q&A 2010-002
Published: 14 January 2010

The Racing Rules of Sailing 2009 - 2012

49.2 When lifelines are required by the class rules or the sailing instructions they
shall be taut, and competitors shall not position any part of their torsos
outside them, except briefly to perform a necessary task. On boats equipped
with upper and lower lifelines of wire, a competitor sitting on the deck facing
outboard with his waist inside the lower lifeline may have the upper part of
his body outside the upper lifeline.

ISAF Offshore Special Regulations 2010 - 2011

3.14.6 Lifeline Minimum Diameters, Required Materials, Specifications
a) Lifelines shall be of :
- stranded stainless steel wire or
- single-braided Dyneema® rope

Question:

Does the term “wire” in RRS 49.2 include Dyneema® ropes as defined by OSR 3.14.6
a)?

Answer:

No. Rope of any description can not be considered as wire. Boats wishing to use the
provisions of the second sentence of rule 49.2 will need to continue to be equipped
with upper and lower lifelines of wire unless rule 49.2 has been changed by the sailing
instructions or class rules to allow the use of other materials.


lot of faith in it

 

[Moody Buccaneer]

It is coming near time to replace the standing rigging on my boat. Or already is time. I have been researching the Dynema Dux and everything I find seems to be at least as good as, and in many cases better than 1 x 19 stainless. Of particular interest is the ability to splice, replace, repair much easier than with stainless wire. Would certainly be much easier to cut loose in case of a dismasting. The need to carry spares would require much less space, and I think would be much simpler. Initial cost apprears to be close to the same, and any future replacement, or repairs much less expensive. Strength is equal or greater. Stretch is claimed to be less. Rigging is pretty simple. Does anyone have any experience with this stuff. I know there will be lots of opinions, so lets hear them too. Not in a great big rush, but replacement is in my near future.

Try to find someone that will size DDux for your boat that *will not creep*.

If don't mind having to retune your rigging every six months to adjust for "acceptable" creep ... go ahead ... have fun ...

Call your insurance broker, if the rig is covered now, will it be with DIY rope rigging?

I've been going around with this for over a year. The information on the website was still wrong the last time I checked.

To keep D Dux from creeping, you have to limit tension to under about 5% of rated strength. At this time I know of no reliable method to measure the tension in rope used for standing rigging.

I think this stuff may have an application, but no one has data on it yet.

There is a reason that real fiber rigging is parallel core PBO with a cover. Navtec does not use 12-strand rope for a reason.

If you would like to read the pissing match about this stuff:

Dynex Dux

That started in September 2008 ...

Yes, I'm the jerk RHough in that thread.

Randy

 

[BobM]

Nice thread on the other site Randy. I am a scientist, chemist, not an engineer, but I must admit that I was less than impressed with the responses you got. In particular it seems like there is a lot of fairly rudimentary weathering and stress testing Dux has not gone through. I thought his "we aren't in the business of spending our $ to test someone else's product" was a particularly telling comment. I'll pass. Each to his own though.

 

[tommays]

3.14.6 Lifeline Minimum Diameters, Required Materials,
Specifications
a) Lifelines shall be stranded stainless steel wire of
minimum diameter in table 8 below. Lifelines
shall be uncoated and used without close-fitting
sleeving.
**
Notwithstanding 3.14.6 (a), temporary sleeving may
be fitted provided it is regularly removed for inspection
**
b) Grade 316 stainless wire is
recommended.
**
c) A taut lanyard of synthetic rope may be used to
secure lifelines provided the gap it closes does
not exceed 100 mm (4 in). This lanyard shall be
replaced annually at a minimum.
**
d) All wire, fittings, anchorage points, fixtures and
lanyards shall comprise a lifeline enclosure
system which has at all points at least the
breaking strength of the required lifeline wire.

 

[Moody Buccaneer]

3.14.6 Lifeline Minimum Diameters, Required Materials,
Specifications
a) Lifelines shall be stranded stainless steel wire of
minimum diameter in table 8 below. Lifelines
shall be uncoated and used without close-fitting
sleeving.
**
Notwithstanding 3.14.6 (a), temporary sleeving may
be fitted provided it is regularly removed for inspection
**
b) Grade 316 stainless wire is
recommended.
**
c) A taut lanyard of synthetic rope may be used to
secure lifelines provided the gap it closes does
not exceed 100 mm (4 in). This lanyard shall be
replaced annually at a minimum.
**
d) All wire, fittings, anchorage points, fixtures and
lanyards shall comprise a lifeline enclosure
system which has at all points at least the
breaking strength of the required lifeline wire.

Make you wonder about people that sell DIY lifelines using Spectra ... CS Johnson is one of many ...

The are called "Lifelines" for a reason ... PVC coated 7x7 wire is a failure waiting to happen.

1x19 uncoated wire is the way to go.

Bonus Question:

Why did some manufacturers use lashing on the lifelines as OEM?

 

[Hermit Scott]

It would unnerve me to be able to dismast my boat with a pair of scissors.

 

[zeehag]

i am also seeking re rigging my ericson--the info gleaned from you is important-and like nice n easy--i donot tend to race , so racing rules are irrelevant!! LOL...shrouds and stays are the standing rigging--LOL--lifelines are optional!!!!!-- i use spectra line for my lifelines..LOL....i CAN!!--i am not bound by racing rules..thankyou for the input!!