Dipping shackles in anti corrosion paint/metal paint

[Brentwales]

Has anyone dipped their shackles in anti corrosion or metal paint and notice any difference in the corrosion? Wondering whether it's worth doing mine on the anchor and mooring shackles.

 

[duncan99210]

Shackles should either be galvanised or made of stainless steel so should be reasonably resistant to corrosion. Dipping mooring or anchor shackles in paint of any sort won’t actually last very long, as it’ll wear rapidly. So, basically, it’s a waste of time (in my opinion anyhow).

 

[pvb]

I doubt that it'll make any difference.

 

[neil_s]

Tar on the threads was considered the best treatment - I find Waxoyl, especially the black underbody seal, pretty good.

 

[Brentwales]

Tar on the threads was considered the best treatment - I find Waxoyl, especially the black underbody seal, pretty good.

Interesting, I'd seen the stuff you can by for antirust for cars, but wondered how well it would last. Do you use it on shackles and how often would you say you need to replace them?

 

[TernVI]

I have used Loctite thread locking compound on mooring parts to good effect.
In addition to a mechanical prevention of it coming undone.
Bitumen paint has its uses, but most mooring corrosion seems to be where rust is quickly rubbed off by motion, so a bit of paint won't help much in most situations.

 

[NormanS]

I use BIG BEEFY shackles, and counter intuitively, I smear the threads with copper grease. They are well moused with monel wire, with a cable tie as a backup.

 

[bitbaltic]

Shackles should either be galvanised or made of stainless steel so should be reasonably resistant to corrosion. Dipping mooring or anchor shackles in paint of any sort won’t actually last very long, as it’ll wear rapidly. So, basically, it’s a waste of time (in my opinion anyhow).

Just been looking at anchor shackles on the Jimmy Green website and that’s exactly what they say.

 

[Neeves]

I use BIG BEEFY shackles, and counter intuitively, I smear the threads with copper grease. They are well moused with monel wire, with a cable tie as a backup.

This is the only answer.

If you can - weld the cotter pin or peen it - forget the wire unless its the only option.

Painting is a complete waste of time and may give you a false sense of security.

Just look at a worn shackle, or chain. The steel is 'eaten' through as a result of a combination of abrasion and corrosion - you are on a hiding to nothing if you think a 20 micron paint coating is stronger than 1" of steel - or will add any more life than an extra 2 days.

If paint worked - we would all paint our anchor chains and chain makers would go out of business.

Shackles, swivels and chains for a mooring cost peanuts just buy the next or 2 sizes up.

Jonathan

 

[William_H]

As said it is all about wear where the shackle touches the chain etc. Only answer is lots of metal to make it last longer. ie bigger shackles. Stainless steel can be used and will not wear but will play havock with iron that they contact so all stainless steel or not at all. Grease tar etc is good if you anticipate needing to undo the shackles but corrosion and seizing is good to keep pin in place (along with sizing with wire) ol'will

 

[Neeves]

The usual reason motivating reduction of wear on ground tackle (or anything else) is to reduce costs and frequency of servicing.

Unless someone can offer an alternative view I really don't see the point of using a stainless shackle, or chain, or swivel. The stainless may not corrode, if the whole assembly is stainless but you are going to increase the rate of galvanic corrosion if you mix the metals. Abrasion is all about the hardness of the metal - there is a direct correlation between hardness and rate of wear and most stainless is soft and will abrade more quickly than a steel shackle. If you use a steel shackle from a reputable manufacturer (which will be more expensive than a no brand shackle) then the shackle is likely made from a high alloy steel and will be harder than that no name product. For a good steel shackle look for Van Beest's Green Pin shackles - obtainable across Europe. But make sure you buy VB Green Pin shackles - their shackles are well known and 'Green Pin' is their brand - and nefarious suppliers will paint their pins green.

Of course stainless shackles will commonly be more expensive than a steel shackle.

But I'm willing to be educated - why mention stainless shackles at all? To me they should not even be considered as an option - unless you are flush, the whole assembly stainless and you opt for duplex stainless (and you don't want to know what a duplex shackle retails for )

Jonathan

 

[TernVI]

There's limited value in buying something like a Green Pin shackle, made of high quality, heat treated steel, then degrading it by welding.
The high specs of Green Pin shackles are out of the window as soon as you've left them in the sea for a week or two.

The normal approach for moorings is to buy cheap shackles and weld them. Just use the biggest possible and don't assume too much in terms of breaking strain. Quite often, mooring contractors buy up lots of used gear, it might be top quality stuff that's been used for industrial lifting but it's old and likely rusty. Or it might be low grade stuff. It doesn't matter, because the load on a yacht mooring is not huge. But the shackles and chain need to be big so that when they've lost half their metal through wear and corrosion, there's still plenty left. I've seen old moorings lifted, two ton clumps of concrete come up on chain that's 80% rusted away. Sometimes they break, because the sinker is stuck in the suction of the mud, maybe 5 T goes on the crane and the broken chain comes up rusted away to a few sqmm.

In my view, stainless can have a use above the water, but again, use big stuff. If you need to trust that a swivel will rotate, you may find a stainless one your best choice, above the buoy. If you don't want rust on your deck, stainless chain is one answer. If you only need a short length, it's not expensive to have it plenty big enough.

 

[Keith 66]

Years ago i put new chains on a half tide mooring, dipped the shackle pins in stockholm tar before i screwed them up (ordinary galvanised shackles) Ten years later replaced the chains, took bolt croppers & hacksaw with me. Tried the shackles & they came undone with zero corrosion on the threads. Cant be bad!

 

[Neeves]

There's limited value in buying something like a Green Pin shackle, made of high quality, heat treated steel, then degrading it by welding.
The high specs of Green Pin shackles are out of the window as soon as you've left them in the sea for a week or two.

I would like to see some data to support any of this.

Members here own 'original' Rocna using a 800 MPa steel in the shank and that shank is welded to the fluke. Despite years of usage of many of these NZ made models - there is not one record of crown failure. In its original version Rocna was Proof Tested, as is the Anchor Right Excel (and both used a 800 MPa steel in the shank and the shank was welded to the fluke). Both anchor passed the Classification Society Proof Tests.

HT steels welded correctly can retain strength and be found to be within specification.

No-one would use a high tensile shackle in a mooring application for its higher strength, or not only for its higher strength. The HT shackle would be chosen for its abrasion resistance. Steel companies have been selling HT steels for their abrasion resistance (primarily to the mining (or related industries). Spot welding, to secure the pin, is not going to impact abrasion resistance of the shackle.

Obviously if you don't mind a shorter life for your mooring ground tackle then buy cheap and cheerful. If you want increased certainty the follow then data. More steel, higher abrasion (HT) resistance.

Some of us buy Crosby G209a shackles - these are quench and tempered, I think the best available - and we use them to secure our chain to the anchor. It does not take long for us to accumulate 'a week or two' exposure to the seabed - you are suggesting they are questionable, basically, as soon as they are used.

Your data would be interesting.

Jonathan

 

[Deleted member 36384]

I imagine TernV1 means welding that is not in compliance with a welding procedure. Of course welded steel can maintain its specified strength but only if welded according to a tested method.

I can not weld, hence any attempt by me to weld closed a pin would likely result in deterioration of the metal properties around the welded area.