Ausbos

Dynice DUX Rig - Looking for feedback

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Hi All, I have finished splicing my first lower shroud and just wanted to get some feedback/advice/criticism on my plan (see photo) before doing the rest. The DUX has been spec'ed for creep using Colligo's stretch table, so the DUX is approximately 3 times the strength of the original wire.

Basically, I am trying to simplify the tensioning of the rig. I want to do this by not having to tie the lashings while simultaneously tighten them. To accomplish this I am using a "whoopie sling" which can be adjusted by pulling the handle when not under load. These whoopie slings have a break strength of 70% of line strength, so should still be well above the old wire strength.

When not underway and I want to tension the rig, I'll rig up a LFR on the deck and lash it with the LFR on the line (see photo). I can then tighten this using a winch or whatever and once I have it at the tension I want I can pull the handle on the sling and release the lashing. 

When underway, if the rig is too loose on the lee side I should be able to just pull the handle to tighten it up.

My one concern is that the sling could loosen itself in some rolly conditions where the rig is swinging back and forth. If anyone can comment on this that would be great.

Can anyone see any problems with this setup?

shroud.jpg

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One thought is to make sure the sling has enough adjustment in the eye, but you should be able to math it out.  

Im not sure I would trust the sling not to creep loose. 

Worse comes to worse you can just replace the sling with a lashing. 

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Without having any testing results to back it up I would seriously question the 70% retained breaking strength for the whoopie sling.  Actually got a bit curious and a cursory search found this:


Recently the reduction to 60% of average break strength for Amsteel Blue whoopie slings was suspected to be a low value. Testing showed that it is actually around 80% depending on the size of the rope. On every test done the break location was at the point of the adjustable whoopie tail exit.

In collusion, the locking brummel has less impact on break strength reduction than the "sudden transition in size where the adjustable section exits the bury". If a traditional buried eye replaced the brummel, the same strength reduction would be expected because the adjustable bury exit is the weakest link.


Best regards,

Mark Pederson
R&D Engineer


Samson: The Strongest Name in Rope
www.samsonrope.com

 

So you might be ok strength wise with your setup.  In any event you do need to anchor the bitter end of the whoopie sling or it will easily slide with a bit of cyclic load.

 

I would personally NOT use that setup for a critical application such as shrouds without a safety lashing at least

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