Re Galvanizing- Learn from my mistake -

[jefndeb]

Hello all-

I had my primary anchor chain (140' of 5/16) hot dip re-galvanized at a local galvanizing foundry, which I think was a mistake in the end...

When I called to ask the foreman about this he said he could do it but that to expect "a few" links might be stuck together. He said all I had to do was to tap a few of them with a rubber mallet to break them loose. He only quoted me $100 so I figured it to be a good idea....Wrong...

I had to spend about 4 hours beating each link with a large heavy hammer over a big piece of wood to break the links apart. And I still didn't do a good job because there are still links stuck together. I probably also broke loose half the zinc coating in doing so

I considered silly stuff like renting a cement mixer and rolling the chain around to work the links loose but I had to do something, I should have bought all new chain but I didn't realize the chain would look like it overdosed on viagra.

I also bought 2 cans of cold zinc spray, which is really just paint with some zinc in it, and tried to re-coat the chain.

Anyway, I do not recommend this to anyone unless the facility is setup to hot dip chain.

I worked it around our Lewmar Concept 1 windlass 3 or 4 times when we anchored this past weekend and it worked fine other than a few kinks and twists here and there, and there are tidbits of zinc chips everywhere in the windlass area and anchor locker.

I say all this because I was under the impression, based from the survey and my ignorance that I had 3/8" anchor chain, which seemed correct for my 40 foot trawler. I had also installed a Rocna 25kg anchor last summer and felt I had a reasonably good setup.

But today a dock neighbor today gave me 120' of fairly new Trident 3/8" BBB anchor chain. This chain he gave me looked surprisingly bigger than my chain which made me question the size of mine.

Turns out after doing some measuring that I have only 5/16" chain.

And it looks like my gypsy would have to be replaced to accept this new 3/8" chain.

Question I am asking after all this bla bla is -

Is there a ABYC recommendation chart to shows vessel length/weight to show proper anchor chain sizes per vessel size?

Thanks, sorry for the long story.

Jeff

 

[Simi 60]

Always make sure the galvaniser tumbles it.

 

[Russell Clifton]

Rocna has a chart: https://rocna.com/fitment-guide/

 

[DavidM]

That Rocna chart looks pretty good. I look at the maximum holding power of the anchor (and that in itself is subjective) and try to match it with the chain's WLL (working load limit). Note that the Rocna chart is for G40 chain (similar to G4) which has about 50% higher WLL than lower strength BBB chain. If you want to use BBB chain then go up one size from the Rocna chart's recommendation.

The shackle is also important. If using off the shelf shackles use one size up from the chain because they are made with mild steel which doesn't have the same strength as G40 chain. You can buy high strength shackles that have the same WWL as the same size chain.

David

 

[Hippocampus]

Was under the impression that due to the toxicity and difficulty of doing this correctly it’s gotten very hard to find anyplace to regalvi chain for use as rode.
Where did you get it done? Is my impression correct?
We’ve been reversing chain then replacing it. What are other people doing?

 

[Airstream345]

Interesting post and timing as we just went through the process of replace or re-galvanize? our chain.

There is a place in Ballard WA that can re-galvanize anchor chain. They use a centrifuge to ensure full coverage and reduce "sticky links". They charge by the pound and can only tumble 200# at a time. This means they need to break up longer chain and re-weld when it comes out. Sandblasting rusty bits costs more at $120/hr. Turn around time was estimated to be 4-6 weeks.

After pricing everything out and considering all of our options we opted to just replace with new chain from WA Chain. About 30% more than re-galvanizing but in stock which means ready to go for summer cruising.

Many folks in our marina simply replace the last 50' using a link or flip the chain around to the clean side.

We bought 300' of 1/2" BBB. Cost was $7.15/ft. Not the sexiest use of boat bucks but I'm of the mind you don't want to wonder about your ground tackle decisions when you're hunkered down in an anchorage and it's blowing 50.

 

[DDW]

The traditional way to do this is not to break apart the links after galvanizing (which also removes a lot of the galvanizing) but to use a chain vibrator as the chain is pulled from the melted zinc. There are not many companies with this equipment anymore.

 

[Simi 60]

Was under the impression that due to the toxicity and difficulty of doing this correctly it’s gotten very hard to find anyplace to regalvi chain for use as rode.
Where did you get it done? Is my impression correct?
We’ve been reversing chain then replacing it. What are other people doing?

Reversing chain was the worst thing we did
Sure we ended up with decent stuff on deck but had 40 meter's of festering mess below that whenever it came out in deep anchorages made a shocking mess on deck with flaking rust.

Now we don't reverse the chain and because we anchor daily the worn section comes up clean and when, several years later, it gets the the stage that it's twisting and skipping through the chain wheel, I chop the affected section and go again, so usually drop 30m and still have a good 50m

For us, an imported box of made in Japan, rated, forged, Acco/Peerless 13mm split links
https://www.peerlesschain.com/products/Oval-Connecting-Links/
joins that section onto the next fresh 80m section.
These links exceed the chain strength.

I Sikaflex the links together to keep water out before peening the pins over.
I also have a soft shackle in there as back up and it seamlessly runs through the chain wheel.

For further details on c- links with destructive testing see here.
C-links – Cox Engineering

 

[Hippocampus]

Thanks so much guys. A huge amount of new information for me and of excellent quality. So that’s now a permanent line item in the budget. Due to cruising grounds and a disre to still use 5:1 instead of the 3:1 some people say is adequate with nextgen anchors this is a considerable expense as I prefer a all chain rode (300’) with rope only used as a tail. . I also don’t like Chinese sourced chain. Who are you using for chain?

 

[DDW]

These links exceed the chain strength.

For further details on c- links with destructive testing see here.
C-links – Cox Engineering

To be completely accurate, the best of the links did not quite make chain strength in the destructive tests. But probably close enough.

 

[Simi 60]

To be completely accurate, the best of the links did not quite make chain strength in the destructive tests. But probably close enough.

Well, they never tested a 13mm link.

The PWB 13mm grade L we use has a SWL of 1700kg and a 4:1 safety factor so 6800kg
https://www.nobles.com.au/en-au/product-catalogue/grade-l-chain

The Acco link has an SWL of 2040kg and a 4:1 safety factor so 8160kg
https://www.peerlesschain.com/products/Oval-Connecting-Links/

Link is stronger than chain

 

[Airstream345]

Thanks so much guys. A huge amount of new information for me and of excellent quality. So that’s now a permanent line item in the budget. Due to cruising grounds and a disre to still use 5:1 instead of the 3:1 some people say is adequate with nextgen anchors this is a considerable expense as I prefer a all chain rode (300’) with rope only used as a tail. . I also don’t like Chinese sourced chain. Who are you using for chain?

Ours is ACCO chain from a reputable supplier (I've heard stories of suppliers saying it's ACCO or USA made when it's not).

Regarding modern anchors, we find our Rocna 55 to do an amazing job in terms of a reliable, good set here in the muddy bottoms of the PNW. We usually drop 4:1 and then back down (drift, then reverse then reverse to 1500 RPMs). I'll payout more if needed and add the bridle (another 20') and we don't move.

With 300' of 1/2" BBB at 2.8 pounds per foot this often means we're usually sitting on the weight of our chain unless it's really blowing or a big tidal swing.

If anything getting the anchor back up can be our biggest challenge. Nine times out of ten we have to get right on top of it, pull the chain tight and drive over it to release it.

While I avoid 3:1 anchorages knowing how these modern anchors perform I'd be comfortable in a calm, tight anchorage with less scope out.

 

[DDW]

Well, they never tested a 13mm link.

The PWB 13mm grade L we use has a SWL of 1700kg and a 4:1 safety factor so 6800kg
https://www.nobles.com.au/en-au/product-catalogue/grade-l-chain

The Acco link has an SWL of 2040kg and a 4:1 safety factor so 8160kg
https://www.peerlesschain.com/products/Oval-Connecting-Links/

Link is stronger than chain

The point was that the Acco link did not achieve its claimed strength when tested. Again, probably enough but I wouldn't bet my life on the brochure strength.

 

[janice142]

I also bought 2 cans of cold zinc spray, which is really just paint with some zinc in it, and tried to re-coat the chain.
Jeff

I did this too, attempting to "save" my chain. Here's what I did: First I scrubbed down the chain with phosphoric acid (ospho), then washed in fresh water. The Next day I used a paint brush to insure there was no dirt or dust on the chain.

Then the spray paint. I used multiple thin coats (3, 4, 5? I lost count) letting my chain dry thoroughly between coats. A week later my chain was again rusting through.

Zinc paint did nothing for me. I bought new 1/4" G4 from http://Defender.com

Anyway Cap'n Jeff, this is an idea that seems good when sitting on the aft deck. In reality, it did not work for me, and I was out cost of the paint.

 

[ORIF]

That Rocna chart looks pretty good. I look at the maximum holding power of the anchor (and that in itself is subjective) and try to match it with the chain's WLL (working load limit). Note that the Rocna chart is for G40 chain (similar to G4) which has about 50% higher WLL than lower strength BBB chain. If you want to use BBB chain then go up one size from the Rocna chart's recommendation.

The shackle is also important. If using off the shelf shackles use one size up from the chain because they are made with mild steel which doesn't have the same strength as G40 chain. You can buy high strength shackles that have the same WWL as the same size chain.

David

Is 1 size up possible?
Can’t remember what I did in my set up.
It may be that I tried to go 2 sizes up and couldn’t because the pin size wouldn’t fit through the chain so I settled for a 1 size up. But I think it wouldn’t allow even one size up. I’ll check later.

I’ve heard that you can have the chain manufacturer make the last link one size bigger. That way it’s factory done and not a weak link. I’m assuming it would involve a custom order or living near the chain manufacturer to get the new link put on. Anyone have experience with this?

 

[Simi 60]

Is 1 size up possible?
Can’t remember what I did in my set up.
It may be that I tried to go 2 sizes up and couldn’t because the pin size wouldn’t fit through the chain so I settled for a 1 size up. But I think it wouldn’t allow even one size up. I’ll check later.

I’ve heard that you can have the chain manufacturer make the last link one size bigger. That way it’s factory done and not a weak link. I’m assuming it would involve a custom order or living near the chain manufacturer to get the new link put on. Anyone have experience with this?

Big load rated shackle in anchor
Smaller load rated shackle that suits the chain but with a throat large enough to go over the bigger shackle is the easiest solution and what we do,

We chop 30 metres+ - off of our chain every few years due to deformity and loss of galv so doing it this way means not having to worry about getting that link re done

 

[ORIF]

Big load rated shackle in anchor
Smaller load rated shackle that suits the chain but with a throat large enough to go over the bigger shackle is the easiest solution and what we do,

We chop 30 metres+ - off of our chain every few years due to deformity and loss of galv so doing it this way means not having to worry about getting that link re done

I’m probably missing something but does the big load rated shackle on the anchor add anything in this application?
Seems like you’re still limiting your strength to whatever the smaller shackle at the end of the rode is rated and a second failure point is added.

 

[Simi 60]

I’m probably missing something but does the big load rated shackle on the anchor add anything in this application?

Yes, you are missing something.

You can get a shackle that suits the big anchor but wont fit chain
You can get a shackle that suits chain but wont fit big anchor
But these two shackles will fit each other

Seems like you’re still limiting your strength to whatever the smaller shackle at the end of the rode is rated and a second failure point is added.

Strength of shackle is stronger than the actual chain, you could even get a HT shackle

Failure points are only there if you let them be.
Every time we weigh anchor the s/s zip tie or split pins depending on shackle are checked.
All pins are loctited as well.