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Dyform wire rigging


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Now that I'm taking the newborn and wifey away on the boat I've become a bit more paranoid about safety, plus i'm thinking of getting my old tub back on the racetrack this winter and hence the rig will get a bit of a thrashing.

 

Hence, I'm looking up the mast realizing that the dyform standing rigging hasnt been replaced since before i bought the boat 10 years ago, and the receipts from the previous owner suggest all standing rigging was replaced in 1998 ie 18 years ago.

 

So, what is the general consensus on when to replace this stuff and is there any tell-tale signs of potential failure I should be looking out for?  

 

FWIW, the rig is a keel stepped alloy section approx 19 m in length, fractionally rigged, with triple inline spreaders (running backstays) with mast-top jumpers.

 

Any insights would be much appreciated.

 

 

 

 

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The insurance companies are saying 10 years, replace.

 

Not all but some so I'd start there, you may have no option if you want to stay insured.

 

Look close and if it looks dodgy them it very well could be. Obviously any broken strands means replace now. 

 

Good point.

 

Does anyone here know if PIC's standard T&C's call this out in their standard policy wording? I really don't want to call them and alert them at this stage.

 

There was nothing obvious to McC when he replaced the running backstays, but he did say "it should be fine for cruising"  when I asked . . . which says alot.

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Good point.

 

Does anyone here know if PIC's standard T&C's call this out in their standard policy wording? I really don't want to call them and alert them at this stage.

 

There was nothing obvious to McC when he replaced the running backstays, but he did say "it should be fine for cruising"  when I asked . . . which says alot.

I think you have just done that

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Good info, thanks Knotty. I'd also heard that Dyform was getting hard to source hence if I decide to replace like for like i may need to look at Hammastrand or something similar

 

Are there any general rules-of-thumb regarding longevity, price and performance for the four main options, being SS wire, galv wire, Dyform/Hammastrand and rod?

 

The reason i ask is that apart from my fore-stay that has a foil on it that dictates size, I'm open to changing if theres compelling reasons to do so. 

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TL, your post made me think about people who decide to go up a size in rigging wire ( often in Wellington - can be windy there :-)). This is potentially not a great idea - extra weight aloft etc, but more importantly the designer chose a wire size for the loads expected, and the supporting structures are designed with those loads in mind, plus a factor of safety. Normally a chain plate, for example, will be stronger than the wire that should be connected to it - better to loose a rig than have a great hole in the side of the boat AND lose the rig! So, if you go up a wire size, other, more serious failures may occur.

Going down a size with similar load capabilities due to new tech, for example, is a completely different thing though, and is often desirable.

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IT is right, If you go down the oversize path on anything and aren't a full engineer who can do all the stress analysis then you should put in place a known weak link that is spec'ed to break at whatever the designer wanted it to break at.

 

On our boat we replaced the rigging with rope that was nearly 3x the break load of what the Designer wanted, As such the shackles from the deadeyes to the chainplate are spec'ed to the designers break load

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I think its all about a happy compromise IT.

 

In my case, I like things slightly over-engineer so the chain-plates and rig stay up no matter what and the whole boat (its a keeler) uses its pendulum effect to rollover and release the load before anything gives way, however that probably not the case with an offshore multi-hull  :razz:

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Yeah KM, it's not just buying the wire again, it's the rig, and the sails and the rest of the damage it does when it all falls over the side due to one bit of crap wire, gear, or termination... Rigging is not a place for compromise.

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