Rocna Size

[Delfin]

Originally Posted by Kettlewell

To be fair to Rocna, a high percentage of other anchors are also made in China these days, including the Lewmars (except for the CQR), which includes the popular Delta anchor. I would guess that most of the knock-off Delta designs, Bruce look alikes, and other plows are Chinese too.

With respect, the issue is not a criticism of the Chinese manufacturers, or Chinese manufacturing in general. Rather it is the allegation that the Chinese manufacturer was directed by Rocna to use mild steel all the while they were representing to the world that they used the appropriate high tensile steel for an anchor designed with a very thin shank. So far, Manson's off the shelf test seems to confirm this allegation. One thing to think about is the very low standard of QC required of an anchor manufacturer. Xray a few welds, and test the metal to see that it is what the specifications require. Not a high burden, so I don't think I would buy the argument that it was all the fault of the Chinese.

Given Rocna's representation of having SHHP and RINA certification when they do not, as well as their tendency to fiddle with anchor testing to distort the findings, I am inclined to think that if a problem exists, it won't prove to be a rogue Chinese manufacturer, but a rogue NZ owner.

[Delfin]

This is pretty much what I have posted elsewhere, but I thought it of general interest here as well. We all care about the safety of our vessels, which is perhaps why this subject interests me.

I decided to go ahead and test a Rocna myself, rather than rely on other's observations. Since I very much need an easily handled stern anchor, I decided to buy the Rocna 22# shown below at West Marine. I figured that if it passed the center punch test, I'd have a good stern anchor that I could also use on my tender, but if it failed, I can always take it back since it would have been falsely advertised. The pictures below show the results of the test.
To start, I used a steel center punch on a piece of mild A36 channel I had lying around. The force used was what you would use to mark a drill spot. The dimple made is shown in the second photo, and the whole piece of channel next to the Rocna in the third.
I then used the same force on the fluke of the Rocna and made the dimple shown in the fourth picture. Rocna says the flukes are made of mild steel. The fifth shot is the dimple made in the shank, which Rocna says is made of 800 MPa high tensile steel. As you can see, the dimple is the same basic indent as that created on the channel, and the Rocna flukes.
To have a reference point of steel with known hardness at the other end of the scale from mild steel I used one of my Japanese chisels, which the catalog shows has a hardness of Rockwell 63, Brinell 255 or exactly the same as 800 MPa steel. I was at first worried about trying to duplicate the same force on the test on the chisel to be fair. I need not have worried. The chisel, shown in the sixth picture was unscathed other than scuffing off some smudge left from woodworking. The center punch however, as shown in the seventh picture is ruined.
I'll decide soon whether I return this anchor as is, or have it further tested, but I thought this indication that the allegation that Rocna is not making their anchors out of the materials they say they are making them out of would be of interest.
Since the Rocna is designed with a thin shank to get the weight distribution optimized, the use of the specified grade of steel is essential if the anchor isn't to present a probable risk of bending under normal side loading and a danger to boaters. Since these anchors set extremely well, the likelihood of side loading one is increased as they are retrieved from deeper burial.

[Steve Pope]

Good Idea! Let your punch do the talking. Now will Rocna respond?

[Delfin]

I doubt it. What can they say? "We specify high tensile steel because our design requires it, but to save a few bucks we use mild steel and lie about it...."

My guess is that they will find someone to blame, and they will sound like the Inspector in Casa Blanca - "I am shocked, shocked to find out there is gambling in this place...."

The better question is how will the retailers of Rocna respond to this kind of information? Keep selling an anchor that will likely bend under normal use? Recall thousands? Can't wait to find out which retailers are as ethical as they say they are.

[JiffyLube]

I replied to your post on this, but one of the moderators decided my reply was either to political or controversial for this thread so they deleted it. It's not your fault they deleted my reply, to your support of products made in that country. I guess they just didn't like how I explained in my words, how we have been letting that country become number one in the world in manufacturing.

Originally Posted by Alecadi

Rob , not wanting to argue for the sake of just arguing.
I've been in China and worked in the industry there for European engineering companies.
Believe me the steel industry is one of the best you can find in the world. China is moving fast, already in front of Japan soon it will be in front of the USA. Wake up. What you said was PERHAPS true some years ago not anymore.
The Steel industry in China represent HALF the word capacity!!
The number one steel producer in the world is INDIA, not Pitsburgh...

Company like Baosteel have the BEST technologies available in the world, Integrated K-H from Thyssen-Krupp, NSC, Arcelor,
system from SMS, Siemens, even Wean United from the US.. etc etc..

They have among the strictest procedures in production, operation, maintenance, quality control and customer services.

They have ISO 9001, API Logo (USA) and JIS

They provide steel to GM, Ford and Chrysler
Nissan, Fiat, VW, Citroen, Honda etc...

and Home appliance manufacturers, shipbuilding, oil and gas transmission pipes, packaging and stainless steel material...

This is 21st century and they are still learning and expanding.

So if you still don't want to buy made in china...

[markpierce]

My boat was bult in China. I'm trusting its quality will compare well to the rest of the world.

[careka]

Rocna, will have to replay on this. We are waiting.


and


Wather will cut any steel, if the pressure is high.

[frant]

Originally Posted by Delfin

This is pretty much what I have posted elsewhere, but I thought it of general interest here as well. We all care about the safety of our vessels, which is perhaps why this subject interests me.

I decided to go ahead and test a Rocna myself, rather than rely on other's observations. Since I very much need an easily handled stern anchor, I decided to buy the Rocna 22# shown below at West Marine. I figured that if it passed the center punch test, I'd have a good stern anchor that I could also use on my tender, but if it failed, I can always take it back since it would have been falsely advertised. The pictures below show the results of the test.
To start, I used a steel center punch on a piece of mild A36 channel I had lying around. The force used was what you would use to mark a drill spot. The dimple made is shown in the second photo, and the whole piece of channel next to the Rocna in the third.
I then used the same force on the fluke of the Rocna and made the dimple shown in the fourth picture. Rocna says the flukes are made of mild steel. The fifth shot is the dimple made in the shank, which Rocna says is made of 800 MPa high tensile steel. As you can see, the dimple is the same basic indent as that created on the channel, and the Rocna flukes.
To have a reference point of steel with known hardness at the other end of the scale from mild steel I used one of my Japanese chisels, which the catalog shows has a hardness of Rockwell 63, Brinell 255 or exactly the same as 800 MPa steel. I was at first worried about trying to duplicate the same force on the test on the chisel to be fair. I need not have worried. The chisel, shown in the sixth picture was unscathed other than scuffing off some smudge left from woodworking. The center punch however, as shown in the seventh picture is ruined.
I'll decide soon whether I return this anchor as is, or have it further tested, but I thought this indication that the allegation that Rocna is not making their anchors out of the materials they say they are making them out of would be of interest.
Since the Rocna is designed with a thin shank to get the weight distribution optimized, the use of the specified grade of steel is essential if the anchor isn't to present a probable risk of bending under normal side loading and a danger to boaters. Since these anchors set extremely well, the likelihood of side loading one is increased as they are retrieved from deeper burial.

Not sure that your metalurgy is correct. The hardness of a material is not proportional to its UTS. The same grade of heat treatable steel can have its hardness adjusted by the heatreating process and hardness becomes a tradeoff to ductility. The chisel would have been forged in the low hardness state and then heat treated or tempered to hold the edge on the blade. The hardness of the chisel must be careful balanced with ductility so that it doesn't shatter in your hand. Doubt that the anchor shank is heat treatable material so hardness not the issue and not an indicator of UTS.

[sailingaway221]

Errrr... I dont really care what they made it out of ... if it was cotton wool and worked and lasted as well as mine has then they can call it graphine for all i care.

[sailingaway221]

Originally Posted by Delfin

I doubt it. What can they say? "We specify high tensile steel because our design requires it, but to save a few bucks we use mild steel and lie about it...."

My guess is that they will find someone to blame, and they will sound like the Inspector in Casa Blanca - "I am shocked, shocked to find out there is gambling in this place...."

The better question is how will the retailers of Rocna respond to this kind of information? Keep selling an anchor that will likely bend under normal use? Recall thousands? Can't wait to find out which retailers are as ethical as they say they are.

Errr. anyone hear of a failed Rocna yet? Mine has definitley not bent at all in 2 years of continuous use and has held through 1 hurricane so far......I doubt very much that the center punch test will be the downfall of Rocna....

[Delfin]

Originally Posted by frant

Doubt that the anchor shank is heat treatable material so hardness not the issue and not an indicator of UTS.

If you look at the Rocna site, you'll see that they advertise that their shank is constructed of "quenched steel", but you are correct, that does not mean that it is tempered in the same way a chisel would be. The reference point of the chisel was used because it has the same hardness as Bisalloy 80, which is the steel used in the Sarca Excel, and I believe the Manson Supreme, and which I referred to as MPa 800 steel. I should have been more specific on how I was managing the comparison. However for the simple purpose of testing to see whether the Rocna shank had the same hardness of the material used in their competitor's products, I think the test is valid if crude. It is also consistent with the Manson tests of the Rocna, which found that they were using MPa 460 steel, and the not MPa 800 steel they advertise.

Incidentally, the result is also consistent with a similar test performed on a Manson with a center punch reported on another forum. In that test the center punch bounced off the Manson shank and did not indent it the way the punch indented the fluke of the Manson.

[s/v 'Faith']

Originally Posted by sailingaway221

Errr. anyone hear of a failed Rocna yet? Mine has definitley not bent at all in 2 years of continuous use and has held through 1 hurricane so far......I doubt very much that the center punch test will be the downfall of Rocna....

Did you see this?



It is in this thread.

[Delfin]

Originally Posted by sailingaway221

Errr. anyone hear of a failed Rocna yet? Mine has definitley not bent at all in 2 years of continuous use and has held through 1 hurricane so far......I doubt very much that the center punch test will be the downfall of Rocna....

Does your Rocna have the name stamped on the bottom of the fluke as shown in the pictures above? If so, then yes, according to their former production manager there have been many reports of bent shanks on Rocnas. Glad yours hasn't, and if it is the Chinese Rocna, as long as you don't subject it to side loading you may be fine.

[Delfin]

Originally Posted by markpierce

My boat was bult in China. I'm trusting its quality will compare well to the rest of the world.

Mark, Chinese manufacturing isn't the issue here. The analogy would be if Diesel Duck specified 1/8" Corten steel for Coot, but told the Chinese builder to use 1/8" A36 instead to save a few bucks.

[sailingaway221]

Yes..... the reason it bent is because it is designed to bend and not to break.... If it had been heat treated as a chisel it would have been brittle and snapped...... bending your anchor shaft under extreme load isn't a bad thing... for it to bend like that it has a tremendous load on it..... and it did not fail...... it held. I would say this guy hooked something and bent the shaft around it...... however even after doing this the anchor did not " fail" ( break ) and set the boat free. Just a little point but the Rocna I have on my boat has a MUCH thicker shank on it than this. It looks like this guy has a small anchor that he loaded up with a lot of weight from a funny direction.... this is not a bad anchor ( under extreme load from 90 degrees to the blade angle of the anchor the shank held the boat in place, showing the shank is strong and the anchor holds even when pulled ofrm 90 degrees to the intended direction of force ) .... its a bad job of anchoring or retrieval.

Failure...meaning the anchor actually broke ( not the chain or the shackle or the swivel ) and set the boat free ...... Not the shaft bent when I pulled it under a rock and bounced my boat up and down on it and reversed around it in circles a few times. Look at the picture and imagine if the shank had not bent to face the pull it was under... there would have been huge load on the shackle and the attachment point on the anchor with a much higher stress .... to me the shank bending saved it breaking.

I wouldn't be at all surprised if that anchor still worked even after the bending... I LOVE my Rocna. Best thing on my boat....just after the girlfriend!