Rusting Rocna

BrianH

BrianH

Well-Known Member
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Messages
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Location
Switzerland
www.brianhenry.byethost18.com
In 2008 I ordered a 15kg Rocna anchor from the then European distributor in Holland. It arrived at my home well packed and then taken to the boat in Italy, still in its original packaging and in perfect condition, to be mounted on the bow roller in place of the original (28 year old) CQR.

After one year of exposure, 13 day's of usage in 7 different anchorages, none of which were in other than sand or mud, the anchor has significant rust spots on the upper stock where the galvanising has gone. The areas of corrosion had not been in contact at any time with any other material so that electrolysis can be ruled out.

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An e-mail to Rocna Anchors support asking for comment has not been answered or acknowledged.

Has any other Rocna user had any unusual rust problems?
 
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made in China?

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That had crossed my mind - the delivery date would fit the news of the change of manufacturing. However, until Rocna Anchors have the courtesy to respond and explain it will remain supposition.
 
From the photos it rather looks as though the galvanising is peeling or chipping off. Is that how it looks in real life? Normally when a dipped galvanised item is damaged the zinc deforms; it can expose iron but the protection from proper galvanising extends some considerable distance. I've never seen anything quite like the example you have posted.

I can't think why China would be an issue; some very fine products come out of China and rubbish can come out of any factory anywhere in the world, if the QA and engineering are poor. My Delta was made in China and that's fine, after a lot of use over two years.
 
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From the photos it rather looks as though the galvanising is peeling or chipping off. Is that how it looks in real life?

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The top example looks like it has been chipped away, perhaps it could have been knocked by the cheeks of the bow roller as it was hauled by the anchor winch, although I cannot remember any incident and certainly expect a level of robustness that could survive that. The CQR that it replaced had no such damage.

The second picture is more of internal rusting breaking through.

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I can't think why China would be an issue

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Nor I under the normal scheme of things. Nevertheless, a change of fabrication to a subcontractor means change and who knows what can slip through a new production environment? My own thoughts about that had nothing to do with Chinese production, per se.
 
Galvanising shouldn't chip or peel. Also, the electrolytic protection extends (i.e. should extend) way beyond the edge of the damage (that is the reason we use galvanising rather than coatings such as paint) while your photo suggests that there is rust right up to the chipped edge. That suggests to me that the zinc is not in electrical contact with the iron in that area. That is possibly why it has chipped. Maybe the surface wasn't properly cleaned and de-greased before they dipped? I've seen nothing like it before.
 
The rust looks grainy wich makes me think of impurities in the metal wich shouldn't happen unless it is cast.
Chinese galvanizing can be quite good,actually.I had a crappy chinese anchor once that didn't hold but never rusted.
 
it almost looks as if, in the second pic, that there has been an electrical short "eating" away the metal. Do you have shore power, or has someone used an electrical lead over the bows ?
 
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it almost looks as if, in the second pic, that there has been an electrical short "eating" away the metal. Do you have shore power, or have you used an electrical lead over the bows ?

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Yes, I have shore power when in the marina but only when aboard and, as I moor aft-to, the lead comes over the stern.

This rusting was visible as soon as I came aboard this spring - I had not noticed any when I laid up last October.
 
the more I look at pic 2, more I think it doesn't look like the high-tensile steel that Rocan uses. The grain size is just "wrong". I can't see rust pits like those appearing without a manufacturing defect such as a blowhole, or through action of an external agent.

I'm sure Craig will be along in due course to set matters right.
 
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the more I look at pic 2, more I think it doesn't look like the high-tensile steel that Rocan uses. The grain size is just "wrong". I can't see rust pits like those appearing without a manufacturing defect such as a blowhole, or through action of an external agent.

I'm sure Craig will be along in due course to set matters right.

[/ QUOTE ]You can see the grain size in the photo? well after 30 years as a Metallurgist I must admit I can't.
What I can see from the pics is poor galvanising with an apparent lack of the Zn-Fe layer which should (will) form if the HDG process is correct.

Most probable causes (based on the pics) are either incomplete cleaning or incorrect temperature / fluxing.
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Artificial Intelligence is no match for Natural Stupidity.
 
I have just taken the anchor down and back up again - the second picture, which is on the top of the shank just before it bends towards the flukes and very deep (90mm) is clearly where it strikes a centre dip in the pulpit. I usually take care to lean it over as it seats but presume there have been times when distracted and not careful enough.

So, mea culpa, the rusting on the second picture is clearly a result of impact(s) when retrieving. Presumably, the first must be too, although the shank is too narrow at that point to impact anything.
 
I dont think your responsible at all. An anchor is intended to be hauled into a metal bow roller/cheeks and intended to be used on rough stone seabeds.That doesnt look like normal wear and tear to me. Anchors that have had hard use for decades dont usually look like that.
 
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So, mea culpa,

[/ QUOTE ] No. That's wrong. Anchors are subjected to rocks, coral and all sorts of abrasive and hard things underwater. The whole point of galvanising is that it is a) soft, b) bonded to the steel and c) protects an area beyond the galvanising itself (it is a sacrificial system). Under those conditions it takes huge damage to result in rust. Your photos suggest that the zinc is not properly bonded to the steel -- i.e. bad galvanising.
 
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You can see the grain size in the photo? well after 30 years as a Metallurgist I must admit I can't.
What I can see from the pics is poor galvanising with an apparent lack of the Zn-Fe layer which should (will) form if the HDG process is correct.

Most probable causes (based on the pics) are either incomplete cleaning or incorrect temperature / fluxing.

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Quite right. I'm not a metallurgist but I did have a hot dip glav plant as well as the steel fabrication factories. It is possible to get tramp elements in the steel that make the galv go funny but the problems above look just like bad galvanising. Not possible to tell from the photos whether the metal was inadequately cleaned before dipping or if some porosity or surface contamination caused the galv process to fail. But hot dip galv isnt just a coating - it form a sort of intermediate alloy with the steel which is why it should never peel off.

Of course it matters if the item is made in China. Would you expect a Chinese car to be as good as a German one? No you wouldnt, and part of the reason would be that the materials used are not yet of the same quality. Ultimately they will be as has happened in Japan. But for ther moment its cheap and cheerful.

Plus I very much doubt that the anchor has been galvanised to a recognised standard like the Euronorms. I might be wrong in saying that and would be delighted to be corrected. But thats the reason why the galv shackles you buy these days are so cr*p.
 
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<span style="color:blue"> I'm sure Craig will be along in due course to set matters right. </span>

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He is usually much faster to react!.. Perhaps we should talk about the Manson Supreme?? /forums/images/graemlins/laugh.gif

João
 
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I have just taken the anchor down and back up again - the second picture, which is on the top of the shank just before it bends towards the flukes and very deep (90mm) is clearly where it strikes a centre dip in the pulpit. I usually take care to lean it over as it seats but presume there have been times when distracted and not careful enough.

So, mea culpa, the rusting on the second picture is clearly a result of impact(s) when retrieving. Presumably, the first must be too, although the shank is too narrow at that point to impact anything.

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Hello Brian,

It seems obvious that you have not received my email returned to you immediately after you contacted us.

We stand by all of our anchors and will repair the galvanising under our warranty.

There is obviously a galvanising problem with this anchor and it must be repaired at our cost.

There is always going to be problems like this occuring with all anchors from time to time and I am not going to say that our anchors are not going to suffer from galvanising problems in the future.

Galvanising can chip or be removed by any number of reasons, the important thing is that we stand by them and stand by our warranty. We have no control over the way our anchors are handled once on a vessel, likewise we have no control over the treatment and processes applied during galvanising. We can only set the specifications for the contractors and trust that they will adhere to those specs.

A walk down any marina will show that every anchor, no matter how well made, will eventually rust to some degree.

We can only do our best to extend the life of each anchor we produce.

This anchor is not a Chinese manufactured anchor and was produced out of the New Zealand facility.

Please email me directly at grant@rocna.co.nz and we can co-ordinate regalvanising of you anchor when and where convenient for you.

It doesnt matter to me if you think you may have damaged it yourself, I will still have it repaired to your satisfaction.

Grant King
Production Manager
Rocna Anchors
 
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...we have no control over the treatment and processes applied during galvanising. We can only set the specifications for the contractors and trust that they will adhere to those specs....

Grant King
Production Manager
Rocna Anchors

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Have you worked in manufacturing long?

/forums/images/graemlins/laugh.gif

Andy
 
Thanks for your response Grant, I'll write later today - it's 01:00 here and I'm tired. As I'm cruising the Italian Adriatic and the integrity of the anchor's functionality is not in question, there is no hurry. Subject is closed from my point of view.

Best, B.
 
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