Anchor metal appearance

[ffiill]

I am an amateur stick welder in so much as over the past forty years I do not practise it enough to become fully skilled.
However I do as a result look at welds from the horrendous stuff done to garden and office furniture to the stuff done on gas and more recent hydro pipes.
I have somewhere a classic mid 20th c book on the art of arc welding full of etched welds cut and polished sections and x rays.
This does not appear to be a weld and even the most sophisticated of machine grinding could not leave such a clean surface and a total impossibility with a hand held angle grinder and why grind the top of the weld off anyway.
Remember the weld theoretically should be between the two pieces of metal with the rod acting as a filler and supplier of the electric arc.
As for material waste when cutting out a shape I do all sorts of things with all kinds of steel plate section and tube and after a couple of years all that is left are a few miniscule bits of scrap.

 

[ffiill]

If it is a Rocna and if it is a weld you have opened a can of worms! Rocna shanks are cut by water jet in order to preserve the properties of the special steel from hot cutting. Welding this steel would require a complete heat treatment to recover its properties.

In my personal opinion much of what comes from Rocna is hype of the same variety that persuades housewife's to buy Persil because it washes their children's clothes whiter!
I dont doubt its strong sturdy self righting and setting but everything else which encourages amateur sailors to part with a lot of money appears to me to be unnecessary hype.

 

[J Neeves]

In my personal opinion much of what comes from Rocna is hype of the same variety that persuades housewife's to buy Persil because it washes their children's clothes whiter!
I dont doubt its strong sturdy self righting and setting but everything else which encourages amateur sailors to part with a lot of money appears to me to be unnecessary hype.

But it does appear to sell anchors - and there is a lesson in there somewhere..

Jonathan

 

[J Neeves]

The position now is that Roberto has tried not to confuse the issue of the 'marks' with the brand. However the brand has now been identified, correctly? As far as I can ascertain there are 2 schools of thought, its a weld or its not a weld, maybe just some sort of accidental localised marking. Advise has been given as to how it might be identified that the mark is a weld or not - and this has not yet been completed. We seem to be left with the idea it actually might be a weld and some suggest that a weld in this location would not be ideal. In order to clarify the position, once and for all, and to protect the innocent - it looks as if Roberto has a responsibility (to the manufacturer, if not to anyone else) to clarify the position.

Jonathan

 

[TernMarine]

I will throw cold water on all your theories ( as amusing as some of them are).
It is a galvanising "dribble" line that results from the run off hen the anchor is lifted out of the hot dip galvanising bath.
It is hung through that hole so the trail of runoff from the hole follows the line you see in the photo.
Depending on the temperature of the bath you have either no ne because it is hot enough or a very thick line because it is slightly cooler than it should be.
In this case it would have been slightly cooler than it should have been and resulted in heavy trail with accompanying slag as it cooled too quickly before all running smooth.
So, nothing more than a bad galvanising job that also shows in the corrosion on the surface.
Iv seen enough of them before to know.

 

[rob2]

At last a believable explanation! All that abuse, huffing and puffing when achieving a welded flat plate without a heat affected zone that would render it useless once the tide turned would make the anchor more expensive than the boat. Gentlemen, as I get steadily older I am trying to learn to keep my mouth shut until I am sure of what I'm looking at. Perthaps we should all consider this.

Rob.

 

[MM5AHO]

I will throw cold water on all your theories ( as amusing as some of them are).
It is a galvanising "dribble" line that results from the run off hen the anchor is lifted out of the hot dip galvanising bath.
It is hung through that hole so the trail of runoff from the hole follows the line you see in the photo.
Depending on the temperature of the bath you have either no ne because it is hot enough or a very thick line because it is slightly cooler than it should be.
In this case it would have been slightly cooler than it should have been and resulted in heavy trail with accompanying slag as it cooled too quickly before all running smooth.
So, nothing more than a bad galvanising job that also shows in the corrosion on the surface.
Iv seen enough of them before to know.

As a galvanizer I feel the need to clarify this.
"depending on the temperature of the bath..." - This varies little in most galvanizing kettles. The fairly standard temperature for normal galvanizing in a steel kettle for jobbing galvanizing work is 450C +/- 5 (ie 445 - 455). Immersion of the steel only cools the bath in extreme cases of very heavy steel, not like anchors. Overheating risks disaster for the kettle, so great care is taken to keep this temp steady. Zinc's freezing point is 419, so all this is happening only just above freezing point.
So nothing is "slightly cooler than it should have been..."
The rate of rise (on the crane lifting the steelwork) determines the rate of drainage of surplus zinc from the surface. If raised too fast, runs can happen. Ideal rate is 0.9m/min rise. Most use about 1m/min.
The hole shown might well have been the place from where the anchor was hung (suspended) by a disposable wire.
Its possible to get a run here of thicker zinc. But that would not result in the picture in the OP, where the zinc must have been thinner.

There's no such thing as "slag" in hot dip galvanizing.
There's "ash" (zinc oxides, and flux residues), that floats on the surface. And there's "dross", which is heavier than zinc and sinks to the bottom of the kettle where its removed by the galvanizer periodically.
Ash gives the appearance of brown dirt mixed with silvery grey partially oxidized zinc. There's no sign of any in the picture.
Dross looks like entrapped sand granules. No sign of that either.

In the image we see a line, vertically down from the hole, where the steel is exposed and surrounding steel still protected by zinc. We can conclude that the zinc was thinner along that line.
Its been suggested that this was a weld. If so, I suggest it had lower Si in the filler wire (assuming mig), or rod (assuming stick weld) and so galvanized to a thinner coating thickness that the surrounding metal. After extensive use the thinner galvanizing was depleted first, and rust starts there.
Galvanizing is a sacrificial coating. It oxidizes away. When its gone, the steel exposed starts to rust.

There's no evidence that this was a "bad galvanizing job" so far brought to light.
The suggestion of a thick like would have showed the opposite of what we see.

 

[Roberto]

thanks all for the interest

Just a bit of additional info: curious about what it could be, I walked along a few pontoons and discovered that there were quite a few anchors of different make (Delta, Bruce, Rocna, etc) with a hole somewhere along the shank that had a very similar appearance to the pictures I posted.
I am no expert and could not tell the difference in very detailed manner, but it was very, very similar. Of course I oculd not brush nor touch the anchors.
In *all* cases the "drip line" was not vertical with the anchor in stowed position, suggesting it may not be some kind of atmospheric corrosion.

Should anyone be interested, do have a look in your marinas for anchors with holes (tripping line or whatever) and check if you see something similar. I stress those I have seen were only only visible in rather (heavily) used anchors, new-ish ones did not show anything.

regards

 

[J Neeves]

I'm not sure why Roberto has not ground a small area at the interface to remove some of the corrosion and gal - and thus settle the issue. It could easily be repaired with paint (the side of the shank is not a high abrasion area) and if its corroding anyway then grinding (or polishing) to metal will make no difference at all, in fact provide a clean surface for the paint (painting anchors is very common - repaint at the end of each season.

I think it unlikely its a weld - simply too much hassle (expense). But stranger things, have and continue to, happen.

Jonathan