Crosby 209A shackles rust!

[Kettlewell]

I've noticed that my Crosby 209A anchor shackles (the high test alloy ones) are prone to rust seriously. It's not a huge deal as long as you inspect them frequently, but I found it disturbing to pull one that had been marinating in the bottom of my anchor locker only to see the metal seriously deteriorating. Other ordinary anchor shackles from Crosby and other brands do not show this level of deterioration under the same conditions. Maybe galvanizing is not as good as it used to be?

[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.

[rslifkin]

As far as failure goes, if the shackle is adequately speced with a working load at least as high as the chain (and therefore a higher breaking strength, as shackles usually have a 5:1 SF vs 3 or 4:1 for chain), failure should be rare. You'd generally see noticable deterioration well before the shackle is compromised enough to risk failure.

[GordMay]

Crosby 209A shackles are mechanically galvanized, in sizes 3/8", and under.
➥ https://www.thecrosbygroup.com/catal...chor-shackles/

According to the American Galvanizers Association, the hot-dip coating [±0.6 oz/ft2/mil] has over 30% more zinc, per unit volume, than the mechanical coating [±0.45 oz/ft2/mil].
The corrosion protection is directly related to the amount [density] of zinc, in the coating.
The mechanical bond, between zinc and steel, and zinc to zinc, is considerably weaker than the metallurgical bond, found in hot-dip galvanized coatings, by several orders of magnitude.
➥ https://galvanizeit.org/uploads/publ...al_Plating.pdf

[Benz]

Higher-strength alloys often corrode faster. G70 chain will deteriorate in damp salty conditions long before G40 is affected. Wichard's high-strength line of stainless shackles corrodes before the regular 316 ones do. It's the trade-off for greater strength.
The quality of galvanizing on the OP's shackle has less to do with it than the composition of the metal.

[s/v Jedi]

Clean with steel brush then prime with Ospho then spray with zinc spray. I believe it’s from CRC.

Best to keep the shackle attached to the anchor on the roller so it dries, cleans and is observed more

[Kettlewell]

Crosby 209A shackles are mechanically galvanized, in sizes 3/8", and under.
➥ https://www.thecrosbygroup.com/catal...chor-shackles/

Thanks for that information! That explains it then. I use the 3/8" 209A shackles (WLL 2 ton) to connect my G4 chain to the anchor and my line. Over the weekend I was sorting through various old hardware on my boat and I even noticed that some 209A shackles I hadn't used yet had a light coating of surface rust just from moisture on the boat. By the way, I looked up the regular Crosby 209 3/8" shackles (WLL 1 ton), and they too are "mechanically galvanized."

[Chotu]

Acco chain is exactly the same. Was very disappointed to see mine rust instantly after buying it.

It's a rusty mess, but too expensive to not use it and buy more (which I doubt is any better).

So, I get happy anchoring in sand where it grinds the rust off a bit.

Pathetic what we are paying top dollar for these days

[rslifkin]

Originally Posted by s/v Jedi

Clean with steel brush then prime with Ospho then spray with zinc spray. I believe it’s from CRC.

Best to keep the shackle attached to the anchor on the roller so it dries, cleans and is observed more

Good point. I do this every year or so with any wear spots in the anchor galvanizing. The zinc spray doesn't hold up as well as the original galv, but it's better than rust on a spot where the galv has been scratched through.

[s/v Jedi]

It’s sold under various names and Pettit sells it for spraying propellers.

https://www.crcindustries.com/zinc-i...-13-wt-oz-571/

[Kettlewell]

So, has Crosby changed how they galvanize shackles? I've got some antique Wilcox-Crittenden and other galvanized shackles decades old that look much better than some current-gen Crosby's used for a season.

[s/v Jedi]

Originally Posted by Kettlewell

So, has Crosby changed how they galvanize shackles? I've got some antique Wilcox-Crittenden and other galvanized shackles decades old that look much better than some current-gen Crosby's used for a season.

My Crosby looks great but I have a 3/4” which reportedly had better galvanizing.

(just checked, I have the G-209 without the “a” so not an alloy version. I can use a 3/4” shackle on my 3/8” G7 chain because I have large end links)

[Kettlewell]

My Crosby looks great but I have a 3/4” which reportedly had better galvanizing.

( just checked, I have the G209 without the “a”)

Yeesh! What size chain does that fit, or is used for something else? I too have some giant shackles like that I have used for mooring pendants for several seasons and they look much better than these Crosbys that are rusting. The rust was actually pitting the metal.

[s/v Jedi]

Originally Posted by Kettlewell

Yeesh! What size chain does that fit, or is used for something else? I too have some giant shackles like that I have used for mooring pendants for several seasons and they look much better than these Crosbys that are rusting. The rust was actually pitting the metal.

I was just editing to add that 3/8” G7 chain, enlarged end links, custom order at Acco chain.

[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.