My new Rocna anchor seems a bit soft

[Deleted User YDKXO]

I bought a new 55kg Rocna anchor over the winter and I had my first chance to use it a couple of days ago. When retrieving the anchor, my SWMBO noticed that the sideplate of our bow roller had gouged a chunk out of the shank

She then got an ordinary serrated kitchen knife and was able to slice a couple of millimetres into the shank without problem

I presume that this is a case of poor galvanising? Should I be concerned that over a prolonged period of use that the galvanised layer will be further damaged and the steel underneath will start to corrode? I have already complained to the yard that supplied the anchor and I am waiting for their response

 

[kashurst]

Stainless steel is usually harder than mild steel so your knife will dig into it. Also if the steel rocna clouts the stainless side plates of the bow roller assembly it will mark it. However I could be wrong, so best to query it.

 

[longjohnsilver]

Sell it by the slice on eBay, you'll probably make a profit

 

[Cheery]

Sell that knife to the contributors on the fouled prop thread.

 

[Hurricane]

Is it an original Rocna or a comaptible.
We haven't fitted ours yet but ours does have an original Rocna label and serial no etc.

 

[SAMYL]

If it is the galvanising that she sliced into then I'm not surprised. Zinc is really quite soft.

 

[Nick_H]

If it is the galvanising that she sliced into then I'm not surprised. Zinc is really quite soft.

Max thickness of galvanising is about 0.25mm, so if the knife went in 2mm then it's well into the base metal

 

[hlb]

Surprised at you Mike. Give the ronca a burial at sea, then buy a proper plow or whatever. It will last forever,if it does go a bit rusty. Give it a coat of Hammerite.

 

[Deleted User YDKXO]

Is it an original Rocna or a comaptible.
We haven't fitted ours yet but ours does have an original Rocna label and serial no etc.

As far as I can tell it is a genuine item as it has a quality control label on it

and a serial number

The Rocna label also states the manufacturer as Canada Metal Pacific who took over the Rocna company in 2011. If it is some kind of knock off then it is a good one

 

[Deleted User YDKXO]

Max thickness of galvanising is about 0.25mm, so if the knife went in 2mm then it's well into the base metal

Well 2mm was a guestimate but it was certainly more than 0.25mm

 

[longjohnsilver]

As far as I can tell it is a genuine item as it has a quality control label on it

and a serial number

The Rocna label also states the manufacturer as Canada Metal Pacific who took over the Rocna company in 2011. If it is some kind of knock off then it is a good one

Does it float? If so maybe it's not genuine

 

[SAMYL]

Max thickness of galvanising is about 0.25mm, so if the knife went in 2mm then it's well into the base metal

Neither of those photos show a cut 2mm deep, much more like a scrape. The piece on the guy's finger is like a bit of tinsel.

I have seen galvanising hardened when it was dripping off the metal and much thicker than 2mm.

 

[Nick_H]

I have seen galvanising hardened when it was dripping off the metal and much thicker than 2mm.

Agreed, but an anchor would be hung from it's eye for galvanising, so there wouldn't be any build up on the shank.

I suppose there's no real need for an anchor to be made of a hard grade of steel, but that does look very soft, and if nothing else it will suffer more dings which will eventually start to rust

 

[z1ppy]

At the risk of starting a long and painful debate, i remember reading a few years back a long and aggravated thread on here about how some of the Roncas were made with below spec steel and it was around the time of the CMP Buy out?

 

[Deleted User YDKXO]

At the risk of starting a long and painful debate, i remember reading a few years back a long and aggravated thread on here about how some of the Roncas were made with below spec steel and it was around the time of the CMP Buy out?

Actually that happened just before the CMP buy out in 2011 (?) but supposedly the quality has improved since CMP took over the company

 

[Deleted User YDKXO]

I suppose there's no real need for an anchor to be made of a hard grade of steel, but that does look very soft, and if nothing else it will suffer more dings which will eventually start to rust

It is very soft. I checked my old Delta anchor which we still have on board and there was no damage on it of the kind we have already experienced on our Rocna. Yes what concerns me the most is that the galvanising will be damaged in various places and eventually the steel underneath will start to corrode. Anyway the good news is that the yard who supplied the anchor have seen my pics and agreed to take the matter up with the local Rocna dealer

The pity is that I would like to continue with the Rocna because the one time we did use it, it performed very well.

Note to Hurricane. Be careful when going astern to set the anchor. The Rocna seems to set quicker and harder than the Delta

 

[Hurricane]

Note to Hurricane. Be careful when going astern to set the anchor. The Rocna seems to set quicker and harder than the Delta

Thanks - I was hoping that would be the case.
From what I've seen when snorkelling our old Delta always made a rut in the sea bed for at least 3m before setting.
I believe that Rocnas set immediately.

We are back home at the moment and deliberately didn't fit the Rocna whilst we were out there during the last couple of weeks.
I'm going out again next Wednesday to lift JW and do bottom maintenance.
The plan is to fit the new anchor when the boat is back on the pontoon (turned round so that her bow is over the pontoon).
I will take some pics and have a close look at the zinc.
In the meantime, here's a pic of ours showing the Rocna logo.

 

[Deleted User YDKXO]

In the meantime, here's a pic of ours showing the Rocna logo.

Seems like there is a nick in the galvanising above the label already!

 

[Neeves]

It would not be very difficult for a Chinese entrepreneur to copy a label. There are copy Rocnas about, you see them on eBay, but I think it unlikely you have one (but not impossible)

Galvanising anchors is difficult. Ones like the Rocna can be made from 3 different steels and each steel reacts in the bath differently, there is a whole history about different steels and how Rocna addressed it - but I'm sure you do not really want to know. Rocna has tried cast and welded flukes and these would usually be a milder steel (but cast flukes can be variable), the shank should be of a highish tensile steel and roll bar something different again (it needs to be bent to shape the other two steels need to be resistant to bending). Because the steels react different to galvanising when the anchor is completed the galvanising on each steel can look 'different' and commonly they are all spray painted with a cheap aluminium paint.

You might be looking at cheap paint.

Galvanising is a metallurgical reaction between the molten zinc and the steel and the galvaniser is trying to make, with varying degrees of success ZnFe alloys, there are usually more than on layer, and the exterior layer is zinc. Zinc is wasted on the exterior of anchors, because its soft and wears off, very quickly, but customers like bright shiny objects (hence the aluminium paint - see above and why we see lots of stainless anchors, shiny does not mean good) and some zinc is 'left on'. The zinc is mostly removed or reduced in a vibrator - (I don't know much about these but I understand the Chinese are famous in the technology ) or a spinner (think spin dryer).

As I mention Zinc is soft - you might be looking at some thick areas of zinc.

It seems very unlikely you can hand cut any steel with a knife, whatever the knife is (most stainless is softer than even mild steel, steel for a knife usually not being what we might consider to be the same as 316 stainless - so there is stainless and stainless).

The galvanised layer could be any thickness upto about 150 microns. If it is really thick, 150 micron, it commonly flakes easily during use. If its too thin it will wear out quickly - the optimum seems to be about 120 microns. The underlayers, those ZnFe alloys are harder than the steel and harder than the HT steel they used to use in the shank. So if you are cutting through the galvanised layer it is possibly not well adhered. But forget the idea galvanising is soft, the zinc is soft but good galvanising is harder than the steel it is protecting.

If its a very soft steel, and you can make a real impression with a knife then it will also bend easily. Lay the shank between 2 supports and jump on it - it it bends, take it back. This might not work if you are sylph like and healthy and you might need to jump from higher up.

Personally I think you probably have a genuine Rocna with some bad finish and that finish will not impact performance one iota. But take another look and, maybe, jump on it.

Jonathan

 

[Deleted User YDKXO]

Jonathan thanks for your comprehensive reply. If the top coat on the Rocna were an aluminium paint that might explain why it was so easy to damage it compared to our previous Delta which was also bought new but was never as bright as the Rocna and may not have had a paint finish. Manhandling a 55kg anchor to a place where you can jump up and down on it is going to be difficult with our boat being moored stern to so I will continue to use it but keep a close eye on it for bending and any further damage

The yard that supplied the anchor inspected it and dismissed the damage as normal wear and tear so until such time as the anchor shows more serious damage I'm going to live with it