Crosby 209A shackles rust!

[betwys1]

[QUOTE=Kettlewell;3839133]I've noticed that my Crosby 209A anchor shackles (the high test alloy ones) are prone to rust seriously. /snip/QUOTE]

I am surprised nobody in this thread mentioned using bronze shackles which excluding electrolysis concerns, seem to have the longest life: example
https://www.classicboatsupplies.com/...0shackle%20key.

[Bellinghamster]

Bronze vs. Galv: Working load limit of a 3/8 galvanized steel shackle is 2000 lbs, minimum breaking strength 10,000 lbs.
The 10mm bronze shackle you linked had a listed breaking strength of 2400kg (5291 lbs). If the same 5:1 safety factor is applied has a working load limit of 480kg (1058lbs).
Half as strong as steel. Of course, could be sized up accordingly to match or exceed the strength of the chain, but that could get bulky over the bow roller.

[rslifkin]

Originally Posted by Bellinghamster

Bronze vs. Galv: Working load limit of a 3/8 galvanized steel shackle is 2000 lbs, minimum breaking strength 10,000 lbs.
The 10mm bronze shackle you linked had a listed breaking strength of 2400kg (5291 lbs). If the same 5:1 safety factor is applied has a working load limit of 480kg (1058lbs).
Half as strong as steel. Of course, could be sized up accordingly to match or exceed the strength of the chain, but that could get bulky over the bow roller.

And that's comparing for a standard steel shackle, not a high strength shackle like the Crosby G209A mentioned in this thread. The G209A in 3/8" is rated for 2 tons (and I'm pretty sure that's metric tons, so 4400 lbs) working load with a 5:1 safety factor.

[Kettlewell]

And that's comparing for a standard steel shackle, not a high strength shackle like the Crosby G209A mentioned in this thread. The G209A in 3/8" is rated for 2 tons (and I'm pretty sure that's metric tons, so 4400 lbs) working load with a 5:1 safety factor.

For some reason the 209A shackles have a safety factor of 4.5:1, so breaking strain would be 19,800 lbs. I wonder if some of the other brands, like Campbell, Chicago, and Titan are hot dipped galvanized still at the 3/8" size and therefore probably more corrosion resistant? They seem to be from what I can read on the website.

[Chotu]

Just a random thing.... a 7/16" shackle is the right size for 3/8" chain.

That impacts the breaking strength numbers above. Favorably

[Kettlewell]

Just a random thing.... a 7/16" shackle is the right size for 3/8" chain.

That impacts the breaking strength numbers above. Favorably

In my case, the chain is 5/16 G43, so a 3/8" shackle just fits. I have read some people manage to get a 7/16" shackle on 5/16" chain, but I have tried several and they just don't fit.

[rslifkin]

Originally Posted by Chotu

Just a random thing.... a 7/16" shackle is the right size for 3/8" chain.

That impacts the breaking strength numbers above. Favorably

Correct. But the above mentioned 3/8" shackle is correct for 5/16" chain. And the 3/8" G209A has a working load just a little higher than the working load of 5/16" G43 chain.

[Chotu]

Ok. Apologies. I had thought we were on 3/8 chain.

[sailingharry]

Originally Posted by gulfislandfred

Do you use stainless steel tie wire, swivel, or any other stainless on your anchor system? Stainless will stay nice and shiny, as it sets up a current to steal the zinc off anything in its electrical path.
As you walk down the docks, look at the anchors on boats. Where there's a stainless swivel on a galvanized anchor and chain, you'll often see the first foot of chain is rusty. Not so common on boats with no stainless in the anchor system. Even a couple of inches of SS tie wire on a shackle will do it. Use galvanized tie wire, or zip ties to mouse your shackles.

I had a neighbor with a galvanized Rocna where the bar rubbed on his stainless bowsprit. No chafe/wear (the stainless was perfect) but the roll bar was rusted nearly through. I always assumed it was a galvanic reaction. Based on that observation, my secondary anchor is lashed to a pulpit leg for secure storage -- but the leg is wrapped with line to prevent contact!

[Kettlewell]

Do you use stainless steel tie wire, swivel, or any other stainless on your anchor system? Stainless will stay nice and shiny, as it sets up a current to steal the zinc off anything in its electrical path.
As you walk down the docks, look at the anchors on boats. Where there's a stainless swivel on a galvanized anchor and chain, you'll often see the first foot of chain is rusty. Not so common on boats with no stainless in the anchor system. Even a couple of inches of SS tie wire on a shackle will do it. Use galvanized tie wire, or zip ties to mouse your shackles.

Nope, galvanized all the way from anchor to rope, and I just use zip ties on the shackles. Interestingly, I do take my Mantus M1 off the roller and hang it on the stainless steel bow pulpit when I am on a mooring, in order to keep the sharp anchor well away from the mooring pendant. The anchor resides there on the stainless for weeks at a time, but has shown no corrosion where they touch. I suspect that is because these items are out of the water and other than moisture in the air there isn't enough electrolyte. OTOH, there are lots of people using SS anchor swivels and even quite a few using SS shackles. Lots of SS anchors in use too. Do they see problems? How about aluminum anchors connected to galvanized shackles and chain?

[Shrew]

I just replaced one. The the two other non-Crosby Shackles were fine. I replaced them all.

[Kettlewell]

I just replaced one. The the two other non-Crosby Shackles were fine. I replaced them all.

What did you replace them with?

[Jim Cate]

Does anyone know if galvanizing the Crosby shackles will affect the strength?

Jim

[Ozzlawrence]

Originally Posted by Kettlewell

OTOH, has anyone ever experienced an anchor shackle failure? I've never come close that I know of, despite some looking pretty nasty and rusty.

Certainly have! I was solo sailing from Snapper Island to Cairns on my way back from Lizard Island. I was absolutely amazed that I didn't lose the anchor. After arriving in Townsville and discussing the failure of the stainless shackle (and another attached to the vang earlier), the anchor shackle was replaced with a rated galvanised shackle.

[Benz]

[QUOTE=betwys1;3841207]

Originally Posted by Kettlewell

I've noticed that my Crosby 209A anchor shackles (the high test alloy ones) are prone to rust seriously. /snip/QUOTE]

I am surprised nobody in this thread mentioned using bronze shackles which excluding electrolysis concerns, seem to have the longest life: example
https://www.classicboatsupplies.com/...0shackle%20key.

The trouble is, the electrolysis concerns are huge: bronze will destroy galvi in an eyeblink.