New shrouds, looking recommendations (update: new T-terminal broke)

[Ülari]

Hi,

Since one of my upper shroud has scratch and needs to be replaced, I am considering going for Dyform. Idea is to replace all 4 shrouds. And now I am looking for a Finnish company that can do it if I send them measurements. I think it would be a simpler solution than finding a way to get it done in Estonia, since places that do terminal pressing does not sell Selden parts.
I was hoping someone here can point me to right direction.
Also pros and cons of Dyform vs standard wire?

[Cage]

If you're just replacing the shrouds, then any shop capable of the job is fine. At least in our boat the shrouds have terminals with holes in them and they are fastened with rig bolts both in the mast end and in the turnbuckles. I think our shrouds have terminals made by Bluewave (not sure, though).

I also recommend replacing the fastenings (or whatever they are called) in the mast where the shrouds are attached. From what I've heard, breaking one of those fastenings is a common reason for rig failure.

We bought our shrouds from https://rig-man.fi/en/.

[harald]

Dyform is regular wired rolled between rollers so the parts are triangular in section. This makes the Dyform wire a little stiffer per area. Most OD-rules don't allow rod, Dyform is the stiffest available wire.

We renewed our wires with Dyform in 2006. Baltic Rigging did them for 190 €. But I think that firm doesn't exist anymore.


This has been discussed here: https://www.fe83.org/forum/viewtopic.php?t=1889 It might be a good idea to check the rake of the mast when ordering new shrouds.

Discussion about rake and renewing of shrouds here: https://www.fe83.org/forum/viewtopic.php?t=727 and here: https://www.fe83.org/forum/viewtopic.php?p=12615

[Panu]

Dyform is regular wired rolled between rollers so the parts are triangular in section. This makes the Dyform wire a little stiffer per area. Most OD-rules don't allow rod, Dyform is the stiffest available wire.

Hi there

In general you can affect the strenght of material by 3 ways:

• Changing material's chemical composition

• Heat treatment

• Cold forming

Dyform uses Cold forming in addition to ( as a "side affect") reducing air gaps between each wire threads. This has direct affect on wire's density (mass / lenght, kg/m) and strength because roll forming makes wire more "solid" and harder.

[Ülari]

Cage, I have hole terminal in turnbuckle end and T-terminal in upper end. Replacing the T-terminal mast backing plate is good advice, didnt even think about it myself, but now seems very logical.

While I know about the benefits of dyform, I am more interested if FENE hull is stiff enough to make the difference. But I think I will get some price quotes first, because if difference is minimal, this should not be even a question.

Harald, looking at picture. Your new shroud T-terminals does not look like original. I have read from Selden manual that T-terminals must match their backing plates. Did you replace them also?

[Cage]

Ah, true, I was completely focused on the forestay. The main and lower shrouds of course have the T-terminals in the mast end.

I ordered the same guy that did our new shrouds (incl. forestay) to change the backing plates. Our new backing plates have bigger holes than our previous ones, which doesn't matter in normal use, except that when raising or lowering the mast the lower shourds have a tendency to fall out.

[harald]

As far as I can remember the T-terminals where exactly the same as the old ones. I didn't even think about changing the plates back then. That day will probably come.

[Ülari]

So about about 4 years ago I replaced all my standing rigging, with dyform (compact strand) 5mm shrouds + forestay. Using Bluewave T-terminals (although, I actually ordered OEM Selden T-terminals, it looks like they were actually Bluewave). On Friday my lower shroud T terminal broke. It was a delivery trip, so we did not have mainsail on, but waves were huge (3-4m) and just as we had put genoa on, it broke. Probably it shock loaded when crashing down from wave. Lucky that we did not have main on, so mast did not broke. Now we put back on our old lower shrouds and I noticed that other side T-terminal had also crack in it. So I guess moral of the story is to always use OEM fittings in that critical places. In few weeks we unstep our mast, then I can check upper shrouds. They might be fine, since longer wire length gives more stretch and therefore lower shock loads, or maybe BlueWave terminals are just rubbish. 5mm shroud should be enough, 6- would definitely be overkill.
Another Idea I had was that maybe lowers should not even be Dyform, so that when it can stretch a bit more, it will have less shock loads on terminals. I will definitely give update when I unstep Lagle III-st mast and have inspected upper shroud T-terminals.

[Ülari]

Saga continues:

We took the boat out of water and as it turns out, upper shrouds also had cracks in same spot.

Company who made wrong T-terminals sent new ones free of charge, but as it turns out some time ago Selden has redesigned T-terminals. They are a bit thicker than my old original Selden shrouds had and they do not fit into old backing plates. So I guess it is time to change the backing plates also. New backing plates have 4 rivet holes, current ones are fixed using 3 rivets (I am not sure if plates inside have 4 or 3). I hope that new plates will match existing rivet holes.