Broken strand on my front rig, looking for opinions.

[meirriba]

Judging from your picture it is not only a single broken strand.
The strands next to it suffered a trauma as well.
I suggest you stay at port until stay is replaced.
Just an opinion of a (retired) surveyor...

[Dsanduril]

Personally this is a pretty easy DIY job, but your confidence level is critical. If I were doing it, here is how I would proceed:

1. Measure the existing wire - You'll need the diameter and approximate length of the wire, the size of the pins where it connects to the beam, the size and type of the terminals. Take pictures of everything. Go to whatever shop you would use (with the pictures) and see if they have the materials in stock. If they don't, have them order the materials. Also check their schedule on making the cable - You could, at this point, decide to switch to swageless terminals and even make the cable yourself, but that is more complicated. Wait until all materials are in stock.
2. Check the weather - make sure no big blows are due for a couple of days.
3. Support the mast with halyards - Run a spare genoa halyard to a strong point on one bow, run a spinnaker halyard to the other bow. Make these up very tight, they will be taking the place of the forestay (with the genoa) that would pull up on the crossbeam.
   
4. Ease the rig at the shrouds (unless you can do it at the forestay/genoa, but many cats have no accessible turnbuckle here) - Carefully mark the screws on the turnbuckles on both the port and starboard shrouds. I wrap a piece of tape around the screw just where it enters the body of the turnbuckle - you want to be able to get these back to exactly where they were. Loosen the turnbuckles 1-2cm on each side of the boat - this removes pressure from the forestay (and thus the crossbeam).
   
5. Tighten the halyards again, this helps to take any pressure off the crossbeam.
   
6. Remove the old wire - Mark the turnbuckle screws (same as for the shrouds). Ease the turnbuckle and pull the pins at each end of the cable.
   
7. Get the new cable fabricated - take the whole thing to whatever shop you are using. Ask them to duplicate the cable. With the old cable in hand they should be able to make up the new one to the same length and same fittings.
   
8. Install the new wire - Confirm that the shop got it right and the cable length matches the old one. Lay out the new wire over the seagull striker and put the pins in each end. Tighten the turnbuckle back to where you have it taped.
   
9. Put everything back - Loosen the halyards slightly. Re-tighten the shrouds to your marks. Check that all is in place. Replace all cotter/split pins. Put the halyards back where they belong.
   
10. Enjoy the sunset

I'm sure I forgot 10 or 20 little things I would do in the process, but that's the basic steps. It probably takes nearly as long to write (or to read and process the information) as it does to go through most of the steps. Personally I'd feel quite comfortable in tackling this task (and have done on our own boat), but that's a very personal decision with an expensive stick hanging on the whole thing. Good luck.

[44'cruisingcat]

Originally Posted by riki

Hi folks, thanks for chiming in, all opinions very well appreciatred.
As for the rest of the riggingit has already been inspected by the rigger and there are no problems and has already been partially replaced.
I am tempted to change the rig myself but i am not sure about how to proceed concerned specially about the pressure the beam receives from the standing rig of the genoa. I'll try to explain better: once i loose the rig that i have to change i'm afraid that the rig of the genoa will pull the alluminium beam......or i am wrong on this one?
Very simply: do you think that it's just a matter of taking off the old rig and replace it or should i be aware about other details?
Cheers

There will be static tension in the forestay that will be placing a bending load on the forebeam.

I'd measure the bridle pin to pin, and get a new one made. Once you have the new bridle on hand, loosen the turnbuckles on the shrouds a few turns (keep count). The forestay should become loose.

This will unload the forebeam. Then you can replace the bridle and re tension the shrouds.

[AndyEss]

Design factors of safety are based on various assumptions, and can include rigorous analysis, past experience, presumptive tables.
Theoretically, with a factor of safety of two, for example, you could cut away 49% of a strength member and still have it hold.
The problem in this situation is the strength member (forestay) is already failing i.e the stay has a proven factor of safety of less than one.
You are lucky - don't push your luck.
Fix it, replace it, but don't count on that stay holding your expensive mast.

[JPA Cate]

Originally Posted by 44'cruisingcat

There will be static tension in the forestay that will be placing a bending load on the forebeam.

I'd measure the bridle pin to pin, and get a new one made. Once you have the new bridle on hand, loosen the turnbuckles on the shrouds a few turns (keep count). The forestay should become loose.

This will unload the forebeam. Then you can replace the bridle and re tension the shrouds.

Good one, 44'. Good thing someone realized it is a cat.

[Dsanduril]

Originally Posted by JPA Cate

Good one, 44'. Good thing someone realized it is a cat.

Originally Posted by Dsanduril

...
Ease the rig at the shrouds (unless you can do it at the forestay/genoa, but many cats have no accessible turnbuckle here) - Carefully mark the screws on the turnbuckles on both the port and starboard shrouds. I wrap a piece of tape around the screw just where it enters the body of the turnbuckle - you want to be able to get these back to exactly where they were. Loosen the turnbuckles 1-2cm on each side of the boat - this removes pressure from the forestay (and thus the crossbeam)....

About half the responses here recognize the nature of the boat and the OP's question, the rest think it is a forestay or something along those lines.

[jmschmidt]

You wrote "front rig, the one on the beam in front" What are you talking about? Is this the forward lower shroud on one side or the other? If you can't describe a key part of your boat in accurate terms should you really be sailing at all?

If you first language is not English then say it in you native language and someone here will translate. Sorry to be so harsh but this tells me a lot.

And GuyFromTheNorth was right on, there could be corrosion in the swage barrel. The underlying course of strands appear rust colored.

[smj]

Originally Posted by jmschmidt

You wrote "front rig, the one on the beam in front" What are you talking about? Is this the forward lower shroud on one side or the other? If you can't describe a key part of your boat in accurate terms should you really be sailing at all?



If you first language is not English then say it in you native language and someone here will translate. Sorry to be so harsh but this tells me a lot.



And GuyFromTheNorth was right on, there could be corrosion in the swage barrel. The underlying course of strands appear rust colored.

Your biography is full of experience delivering catamarans yet you can’t figure out what he’s describing even though it’s in the multihull forum? I understood him completely and I’m a self professed dumbass.

[FLLCatsailor]

I hope you don’t have an issue and the investigators from your insurance company don’t find this post.

Stay on the dock until you get it sorted.

[Red Sky]

Wanna have 4 people all say “Oh shit” at exactly the same moment...have a rig failure.

[44'cruisingcat]

Originally Posted by AndyEss

Design factors of safety are based on various assumptions, and can include rigorous analysis, past experience, presumptive tables.
Theoretically, with a factor of safety of two, for example, you could cut away 49% of a strength member and still have it hold.
The problem in this situation is the strength member (forestay) is already failing i.e the stay has a proven factor of safety of less than one.
You are lucky - don't push your luck.
Fix it, replace it, but don't count on that stay holding your expensive mast.

The fact that the wire has started to fail doesn't mean it was under specified. Wire has a finite life.

[cal40john]

As bad as a mast coming down is, wouldn't this be worse? What gives first after the pelican striker goes? Wouldn't this cause the bows to flex in and cause major fiberglass damage in the hulls?

[Sos]

Originally Posted by Time2Go

Having been dismasted on my friends boat
due to a stupid decision to go out with a
similar “broken strand” ( lower shroud)
I’d stay put and fix it or have it fixed
Now a follow up question for the riggers and
scientist types
I have been told that when a strand breaks
like the one in the picture, the decrease in strength
comes from the fact that the swage becomes
compromised and that the rig comes down
because the cable pulls out as opposed to
actually parting. This is what happened to
us which caused the mast to come down
Comments please
would like to understand the physics
cheers
neil

I would be surprised if the swage could fail due to a broken strand. The strand is still in the swage so the pressure should not reduce?

[44'cruisingcat]

Originally Posted by cal40john

As bad as a mast coming down is, wouldn't this be worse? What gives first after the pelican striker goes? Wouldn't this cause the bows to flex in and cause major fiberglass damage in the hulls?

It really depends on the forebeam. But yes, in some cases it could cause quite a bit of damage.

[riki]

Thank you for all the information and for taking time to respond.
Got an online quote for the rig (quite cheap) and even if very tempted by the DIY way, as i never did it before and never saw doing it, i prefer to wait the rigger and avoid messing with such a delicate part: i don't feel this time to learn how it works the hard way.
Cheers