Rocna Size

[Bash]

Originally Posted by ActiveCaptain

In all seriousness, what percentage of people who bought a Rocna like me know any of the hardness specifications of their anchor? I honestly never saw any numbers or looked into them when I decided to try the thing. All I cared about were the real world results that a variety of people were experiencing with the anchor.

My guess is fewer than 2% of people with Rocna's know what these ratings mean.

I think your estimate is low here. Previous to purchasing my Rocna, I knew of Rocna's specs because their people had been touting those specs to support the fact that their anchor was so much more expensive than that of the competition. This may indeed have been a big part of why I ultimately purchased a Rocna. Previously, I had gone from a real Bruce (three boats ago) to a knock-off "bruce" (two boats ago), and was very much aware that cheap materials made for anchors that performed poorly. So when Rocna made the argument that they were using the good stuff, I went ahead and bought one.

Make no mistake: I'm hanging on my Rocna as I write this. But even though mine was made in Canada, I have significantly less faith in it than before this thread was started.

[Steve Pope]

Like Bash I love my Rocna, tried and true, NZ made at the time Peter was overseeing their manufacture and before his selling to the present owners. would I purchase another one, No, as until this apparent failure of the stock of the several photographed on this site plus however many have been bent but havn't been photographed has been satisfactorily explained by Rocna.

[Cormorant]

I'd like to see some side-force tests that will give practical answers to some of our theoretical questions. Most anchor tests do include 90 and 180 degree veers, but the focus is usually on resetting ability, not on the conditions that might lead to shank bending.

(Though the 1995 Sailing Foundation tests in Puget Sound bent the shank of a Fortress 37 -- mostly because the durn thing held tight under 4000+ lbs of pull, from all angles.)

One test would be "real world" based -- set anchors in hard clay/sand bottom, or whatever will hold the flukes the strongest. Back down to several thousand lbs pull -- whatever pull it would take to simulate, say, 50-knot winds on a 40-foot boat, with some significant wave action thrown in. This is something any cruiser might realistically encounter in the course of several years. Hold steady on that pull for a half hour, maybe angling off 5 degrees side to side to simulate a boat at anchor in storm winds and waves. Get the anchor good and dug in. Then simulate a strong wind change -- veer off 90 degrees and pull sideways at X lbs for 10 minutes. Does the anchor reset, or does the shank bend? Inquiring minds want to know.

Paradoxically, in a 90- or 180-degree veer, at some point there might be such a thing as too much holding power. You want an anchor that holds rock solid in a straight pull but is willing to rotate and reset quickly if pulled from the side, rather than letting the shank bend.

Then a destructive lab test -- clamp the anchor in place and begin pulling on the shank at 90 degrees. At how many pounds pull does it begin to deform? Keep pulling. Does it ultimately break? Would an anchor ever hold to the bottom at this X pounds side pull?

Not sure what company or organization would be willing to fund it. . . . But it would certainly lay to rest a lot of speculation.

[estarzinger]

This is the famous venice 2009 bent anchor.

What does anyone make of the bent stainless swivel (that I have circled). It's a bit puzzling to me. That's a pretty hefty chuck of stainless. I would have thought it would take some hard work to bend it that way. Also, the bend looks to be in the opposite direction to the bend in the anchor. I am not questioning the authenticity of the photo because that seems to have been well established, but just trying to better understand the loads and situation that could have caused the stainless to bend. Any thoughts?

[Shawn67]

Again referencing YBM but for side pull test numbers....

Yachting and Boating World Forums - View Single Post - I hate to do this...but
I hate to do this...but - Page 60 - Yachting and Boating World Forums

If those are accurate the bis80 shanks are over 70% stronger then the 450mpa shanks.

Shawn

[noelex 77]

Originally Posted by estarzinger

This is the famous venice 2009 bent anchor.

What does anyone make of the bent stainless swivel (that I have circled). It's a bit puzzling to me. That's a pretty hefty chuck of stainless. I would have thought it would take some hard work to bend it that way. Also, the bend looks to be in the opposite direction to the bend in the anchor. I am not questioning the authenticity of the photo because that seems to have been well established, but just trying to better understand the loads and situation that could have caused the stainless to bend. Any thoughts?

The swivel is not bent its designed to be that shape. The idea is that its unstable upside-down so it rotates the anchor when retrieving it. It automatically rotates the anchor the right way on the bow roller.

If the shackle jammed (which is a common problem on anchor stocks) it would however, create a much longer lever arm and explain how the anchor bent.

[Opie91]

Originally Posted by impi

I posted this on another thread. Im really concerned having bought my Rocna now.

Guys excuse the lengthy response - but after having purchased my 33 Rocna and then reading this forum, I went back an challenged the supplier.
I take no responsibility for the contents of the letter that was sent to me but here below is what I received:

The purpose of this letter....

As a result of the discussions on the forums and speculation regarding the steel quality of Rocna anchors, Manson Anchors undertook testing comparing the strength of two Rocna anchors against their own anchors. This testing uncovered a discrepancy in the strength of the steel used in the Rocna compared to our own published specs.
This was naturally a great concern to us, as our recent material testing has shown no such discrepancies. On further investigation, we discovered that for a short period of time (during the first quarter of 2010) Grant King, who was Production Manager at the time, approved material from a different steel supplier on the basis that it was equivalent spec to that previously used.
Manson’s testing indicates that this is not the case, and that while still a high tensile steel, it is in fact of a somewhat lower specification to that previously used.
We are confident that although the high tensile steel used during this period was of lower specifications, anchors made with this material are still fit for purpose. We have not seen any increase in warranty claims that would indicate cause for concern.

I went to Rocna's website to look at their warranty policy and found this about construction quality:

Coverage
Rocna warrants that the product will conform to its specifications and will be free from material defects in and failure of material and workmanship from the date you purchase the product.
In plain English: This means the warranty covers standard things like the grade of steel and welding quality, and will not fail when used as intended.

I do not own a Rocna, but would not have a warm and fuzzy felling about something that was "fit for purpose".

Has anyone tried to return a "China" made anchor due to quality defects? It seems to me that is the way to find out if Rocna will stand behind their product.

[estarzinger]

Originally Posted by noelex 77

The swivel is not bent its designed to be that shape. The idea is that its unstable upside-down so it rotates the anchor when retrieving it. It automatically rotates the anchor the right way on the bow roller.

Ah, thanks, yes I just found it on google and you are right, its designed to be that shape. Had never seen one of those before.

[GordMay]

Originally Posted by estarzinger

Ah, thanks, yes I just found it on google and you are right, its designed to be that shape. Had never seen one of those before.

I've neither seen one of those offset swivels, live nor online.
What brand is it, or what website url?

[estarzinger]

Originally Posted by GordMay

I've neither seen one of those offset swivels, live nor online.
What brand is it, or what website url?

Anchor Trimfix Single Swivel

see about half way down this page:

Fortress Marine Anchors, Guardian Utility Anchors, Anchor Trimmer Douglas Double Swivel, Anchor Trimfix Single Swivel, Danforth Type Anchor Other From Italy

[Silent Knight]

Originally Posted by Cormorant

I'd like to see some side-force tests that will give practical answers to some of our theoretical questions. Most anchor tests do include 90 and 180 degree veers, but the focus is usually on resetting ability, not on the conditions that might lead to shank bending.

(Though the 1995 Sailing Foundation tests in Puget Sound bent the shank of a Fortress 37 -- mostly because the durn thing held tight under 4000+ lbs of pull, from all angles.)

One test would be "real world" based -- set anchors in hard clay/sand bottom, or whatever will hold the flukes the strongest. Back down to several thousand lbs pull -- whatever pull it would take to simulate, say, 50-knot winds on a 40-foot boat, with some significant wave action thrown in. This is something any cruiser might realistically encounter in the course of several years. Hold steady on that pull for a half hour, maybe angling off 5 degrees side to side to simulate a boat at anchor in storm winds and waves. Get the anchor good and dug in. Then simulate a strong wind change -- veer off 90 degrees and pull sideways at X lbs for 10 minutes. Does the anchor reset, or does the shank bend? Inquiring minds want to know.

Paradoxically, in a 90- or 180-degree veer, at some point there might be such a thing as too much holding power. You want an anchor that holds rock solid in a straight pull but is willing to rotate and reset quickly if pulled from the side, rather than letting the shank bend.

Then a destructive lab test -- clamp the anchor in place and begin pulling on the shank at 90 degrees. At how many pounds pull does it begin to deform? Keep pulling. Does it ultimately break? Would an anchor ever hold to the bottom at this X pounds side pull?

Not sure what company or organization would be willing to fund it. . . . But it would certainly lay to rest a lot of speculation.

Perhaps Rocna should fund it?

The other paradox is that, as far as I know, Rocna have produced not one shred of documented evidence in support of their claims. No test results. Nothing.
They promised to produce independent test results several weeks ago ("as soon as possible").
Nothing.
They promised to produce copies of documents from their own QA system.
Nothing

[estarzinger]

Originally Posted by Cormorant

I'd like to see some side-force tests that will give practical answers to some of our theoretical questions

Originally Posted by Silent Knight

Perhaps Rocna should fund it?

I would be surprised if West Marine had not already done the bench test.

They could do it in 2 hours at almost no cost - take a ROCNA and a Manson and a Delta out of inventory, clamp the flukes to a strong bench, pull the shank sideways with a load cell, measure the strain at each incremental 1cm of deflection, note when elastic deformation yield strength is passed (when it will not snap back to original alignment) and when ultimate tensile strength is passed (when it breaks), graph and compare.

Given what we now know about the steel quality and shank dimensions, I suspect the results show the Chinese Rocna's elastic yield are on average measurably less than the Manson. And the remaining question is whether it is 'suited for purpose' - which is really a judgement call rather than analytical.

[Delfin]

Originally Posted by Opie91

Has anyone tried to return a "China" made anchor due to quality defects? It seems to me that is the way to find out if Rocna will stand behind their product.

Yes, I did to West Marine, and they covered it immediately, even though what I returned was a pile of cut up metal.

The Rocna warranty seems a bit contradictory. The language guaranteeing that the anchor "will conform to its specifications" is clear, although their "plain english" interpretation of what that language means certainly is not. You can't tell whether the anchor meets specifications unless you test it, and the anchor isn't intended for cutting up and testing. Catch 22! However, if you bought it from a reputable retailer, their business practices, and not Rocna's, should determine the outcome of a return.

[Shawn67]

"Has anyone tried to return a "China" made anchor due to quality defects? It seems to me that is the way to find out if Rocna will stand behind their product."

I'm not sure that tells you if Rocna is standing behind the product or not.

For example in Delfin's return it was West Marine that accepted the return. The store manager made the call to accept the return, not Rocna. IOW, West Marine stood behind the product they sold. We don't know what will happen next when West Marine initiates the warranty claim with Rocna.

Shawn

[Delfin]

Shawn, in all chain stores I know of, to get shelf space you have to unconditionally warrant your product. For example at Costco, you can bring back anything you buy from them basically anytime and they will give you a refund. The manufacturer builds the cost of such returns into their pricing. So, Rocna will credit WM for any returns, whatever their warranty says. If they don't they won't be selling any more anchors to WM.