SO 34.2 Standing Rigging

[MickeyB]

d**n and blast.  My 7mm main rigging snapped at the join on deck.  I took a look and it appears all need replacing, suppose it is about time, at least 10 years old.  Luckily the other 10+ rigging will keep the mast up, but I have jury rigged the line for safety.

So, if I am doing the entire rigging, should I go with Dyneema.  Thoughts? Advice?  Have you done this?

If I go with wire, or Dyneema, can I do it myself?  Do I have to measure each or can I get the measurements required somehow?  I have shamefully ignored much of the rigging as it just gets on and does the job, so I am learning lots now.  I always looked for splits etc, but never actually investigated rigging, which is proving to be rather interesting and a HUGE subject.





Any and all advice happily accepted.

Mike

[johannes]

Personally I would not go for dyneema on a cruising boat. I think the technology is too immature, I would like to see the real-world experiences from more people over longer time. Dyneema creeps over time so it has to be re-tensioned regularly. It is also less resistant to chafe and cuts.

Replacing wire rigging is reasonably simple. Unstep the mast, either yourself or pay someone to do it. When the mast is horizontal, disconnect all the rigging and measure to <1 cm accuracy. Place an order for new shrouds with the correct type of terminals. There is probably a local supplier, or a web store in your country, and they should have instructions how to measure.

When the mast is down, do some maintenance on it: wash it, rinse with the fresh water, and go over it with car polish. Use chrome polish on the stainless steel parts. Inspect everything and replace worn or suspect parts. You may want to replace the electrical cables depending on their condition.

When you step the mast, first attach all shrouds and stays and hand-tension the turnbuckles (don't forget the special grease for the threads). There are several guides online how to tension the rig, or pay a rigger to do it. It is not a particularly difficult DIY job.

[rene460]

Hi again Mike, that is an interesting fracture pattern.  The break is clean and photo is good enough to put in a text book, but I can’t remember what the caption should be, possibly some type of fatigue?

But the point is that it is a failure and I assume that all the rigging is a similar age.

The trouble with the stainless steel we all use on our boats is that it really does not like the chlorides that are in sea water, though the appropriate grades seem to last well at normal temperature.  So the real problem is the early sign of corrosion (intergranular or chloride stress corrosion I think it is called) is not at all visible.  This is in contrast with the galvanised wire used of old, on which the rust was clearly visible and under the rust it was still mostly sound.  So as far as the wires are concerned, you could judge the condition of a galvanised wire, but you can’t tell on a stainless wire.  The most consistent advice I have seen is that the first broken strand is the sign that the wire should be replaced, even though the other strands look ok.

But the threaded rods of the turnbuckle!  The root of the threads can be a bit sharp allowing the salts to hide there.  Hard to tell of its one “rough one” or typical.  Or is it vibration due to wind on the rigging?  I would suggest that one breaking is a probably a sign that all should be replaced for another ten years peace of mind.  And with with roll swaged connections, you would replace the wire while you are at it.  Much better than waiting until a critical one goes.

I am particularly interested in this one as we are also approaching ten years.  I had it inspected top to bottom by a rigger at seven, so I will be getting it carefully looked at this time, later this year.  Or the insurance company may make the decision.  Again, most interested in what others think.  Some problems mean when a fault is found, trouble shooting is definitive, but like the bearing wear, this is another of the difficult ones.

rene460

[johannes]

The threaded part breaking is unexpected, it makes me suspect there was an original manufacturing defect, or later damage specific to that point. The whole turnbuckle assembly in the pictures has a lot of surface corrosion. It is a good idea to service the turnbuckles every few years. This is what I do every year, but then of course I take off the mast every year:

- Disassemble all parts
- Clean everything with degreaser
- Clean the threads on the turnbuckle and the shroud terminals with a high-pressure washer
- Polish all surfaces with chrome polish
- Inspect for damage
- Add new turnbuckle grease to the threads before reassembly

The part I am most worried about is where the terminal is pressed on the wire. The joint is not really possible to inspect.