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Old 29-07-2012, 22:42   #46
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Re: Well Done Rocna

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Originally Posted by impi View Post
Ok ... I had a really good chuckle at your 'Lord of the rings' comment

Obviously you are involved with anchors? You speak from a very technical platform but we heard much of this before and still ... how many boats do you know of that have been damaged due to a faulty Rocna ?

Personally ... none I know of and I know a serious number of SERIOUS world cruisers using them. Do you think we are all just lucky?

Honestly ... the whole thing is just a 'storm in a tea cup', and of course that's the way competitors to Rocna would like it, and there are plenty of them lurking about ...
Rocna's design was always good; the problem was we were told that one grade of steel was crucial to its proper working as an anchor, and it was built with a lesser grade. Now, with CMP owning Rocna, we are now told that a lower grade then originally speced is OK.

What is one to believe?
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Old 29-07-2012, 22:50   #47
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Re: Well Done Rocna

I have a 88 pound Rocna and am extremely happy with its performance. I call it a handbrake...cause that's what it feels like when we set it. I went for the biggest that would fit in our anchor well. We are on a 47 ft cat and we sleep well at night.
Kudos' to Rocna.
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Old 29-07-2012, 22:53   #48
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Re: Well Done Rocna

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It would be my understanding that when anchored in an area subject to tide what might normally happen is at the chage of tide the yacht re-orientates itself, gently, and as the tide flow increases, gently, the anchor would either pull out or swivel round. The anchor will make these manouvres 'slowly'. In the event the anchor did not swivel or pull out and was oreintated 'backwards' the load would be along the length of the shank. In the scenarios I describe and envisage I can see no reason for any anchor to bend. If the anchor is aligned at 90 degrees - it is possible (it would bend) but it is unlikely it would bend prior to swivelling or pulling out.
***SNIP***
There would apear to be too many still out there, ready to bend (easily) as evidenced by Steve's post, above.
I don't think things played out quite like you envisage. For about three hours centered on peak current flow, our boat would "sail" up on the anchor due to our deep fin keel. Once the rode was about 90 degrees to port or starboard off the bow, the boat would fall off. Occasionally the boat would "sail" up so far the rode would get wrapped around the keel when the boat fell off. This was obviously an untenable situation, so with some experimentation I was eventually successful with setting the rudder so the boat would essentially heave to and "park" at the maximum pull. I don't know how much force we were putting on the rode, but it was bar tight and we were amazed at seeing the rode extending straight out 90 degrees from the bow. The point being that for hours there was a significant pull on the rode and the anchor was deeply buried in dense mud (we verified the bottom when we eventually pulled up the anchor to leave). Then at each tide change, the boat would slowly fall back, drift across the anchor and then sail up to the opposite side of the anchor as the current increased. This essentially pulled the anchor to the right each time it happened, and that was the direction of the bend. Given the fact that the boat always sailed up to the same side of the anchor (i.e, to the same side of the shank) in the manner it did, I think it is safe to say the anchor didn't just flip over but tried to pivot sideways over and over. Given the density of the mud and the fact that our GPS showed us within a circle of diameter I would expect given the length of our rode for the four days, I suspect the anchor slowly turned as opposed just flipping over and resetting each tide change. And given the amount of pull I saw, I am certain the anchor was deeply buried each time.

Anyway, long story short, I think your statement that "If the anchor is aligned at 90 degrees - it is possible (it would bend)" is what happened in this case, and your statement that the anchor "bent easily" was a misstatement, or at least it was in my opinion. Given the shank had about 1/4" of bend after the four days of what I describe above and we remained locked in place despite the poor conditions (from an anchoring perspective), I was quite pleased with the performance. Especially with the fact that it apparently reset all those times and held solidly. Would I prefer to not have had to deal with exchanging the anchor? Sure, but if the new anchor performs as well as the old one and has an even stronger shank, I am perfectly happy with it...
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Old 29-07-2012, 23:07   #49
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Re: Well Done Rocna

I would concur with something I detect in your last post, lightening up can be good for the soul!

I confess I know of no-one who has suffered anything more than inconvenience as a result of their bent anchor. But I'm not sure that is the issue. They might have suffered from apoplexy when they discovered the background - but that was not your question and it probably depends on the personality. But I do know of one owner of a Rocna, bent in a situtation almost word for word the same as the one you describe (different Caribbean island, different brand of multi), who had it replaced - and the replacement bent as well! They were unlucky, bought at the beginning of the fiasco and had it replaced before the fiasco was discovered. And they are blue water cruisers, roughly completed half their circumnavigation (and knew little of the story).

Rocna has actually served some good. Companies are on notice, they are being watched and will not be easily, nor cheaply, forgiven. It was a good lesson. It has also brought anchors (and anchor companies) into the limelight and people are a bit more questioning (and more questioning of magazine reviews, on anchors and other things). Hopefully companies will note that slagging off the competition can be counter-productive and many do not like it (and by analogy do not like people who do it). It might be 'good clean fun' for some, but not all.

I like to think I know a little bit about anchors and much of my experiance has been learnt, like yours, at anchor or anchoring, every day, day after day. One has a different view, of anchors, if your home actually relies on one (and we do get defensive of our anchors in same way we are defensive of anything to which we are wedded).


I'm sorry but my only exposure to trolls recently was the film (I read the books at school). I did wonder if the location of the filming and the old location of Rocna was the clue (and tried to follow that line of thought without success, though there could be some amusing twists) - but I was way way out! Is it an 'americanism' or am I just getting old?
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Old 29-07-2012, 23:33   #50
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Re: Well Done Rocna

Pyxis,

Thanks for the background.

There is some 'information' on your story - its all a bit seat of the pants but

Most marine diesels with a clean prop produce about 100kg of thrust for every 10hp at cruising revs. So if you have a 50hp engine and it moves your yacht at 6 knots then you have about 500kg of thrust. Conversely if your yacht sits in 6knots of tide then the resistance, load on the chain, is about 500kg. Someone somewhere will be much better able to conduct the calculations. Might be more under the conditions you describe or less if your yacht is smaller, 30hp engine moving it at 6 knots would be 300kg etc. But very much guesstimates.

Rocna and others have done some calculations on anchor shanks, and most modern anchors have similar shank profiles but the load necessary to (start to) bend a Rocna shank with a yield stress of 780 mpA would be

20kg 795kg
25kg 745kg
33kg 710kg
40kg 1122kg

but with a 480 mpa shank (and some were 355 mpA)

20kg 489kg
25kg 459kg
40kg 691kg

I do not have figures for the current spec of 650 mpa yield stress.

And the reason the 20/25/33kg anchors have similar yield loads is they are all built from 16mm steel plate (there is no scaling)
- other anchor makers are guilty of the same problem, the next plate size up is 20mm - its too thick!

Experiments have been conducted on an actual anchor (10kg) to verify the calculations and they seem to be fairly accurate. At the loads quoted a slight bend will develop, over an approx 20 second period (over 4 days - no idea). Interestingly the thrust developed by the engine of a yacht is sufficient to bend a Rocna with a 480 mpA shank.
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Old 30-07-2012, 09:13   #51
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Re: Well Done Rocna

I'm thinking that if the differnce between the anchor failing and not failing is whether it is 35k yield steel or 45k yield steel.... they have a design problem.... I'm amazed that any anchor would bend as often as apparantly is occurring, they all bend now and then, but if the shank is bending from a change in tides and the anchor's not stuck in a rock etc... somethings wrong! JMHO
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Old 30-07-2012, 11:55   #52
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Re: Well Done Rocna

Rocna's history is long and there have been many voices. Some calm and some shrill. Rocna's reputation has taken a very well deserved beating. With time and a good track record they may recover. Time will tell if the current Rocna anchor spec it up to real world conditions.

But in any case it would be foolish to place blind trust in that anchor. Or any other anchor for that matter.

Attached is a photo to remind us where it started.

Regards

PS If Rocna were to start building anchors to the original NZ spec and steel I would buy one asap. They do fit my bow roller better than the Manson I replaced my Rocna with. (there were a number of problems with the Rocna I replaced, a 33 KG model)
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Old 30-07-2012, 12:39   #53
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Re: Well Done Rocna

What your photo neglects to show is the size of the anchor for the weight of the particular vessel ... I go on the fact that I live on my anchor every day and have anchored every day in various parts of the world ... would not change my Rocna out for any other based on my experience of what it has done for me in conditions where other boats dragged and broke loose. One thing about Rocna ... may have had undersized (for the job) shanks bend but never heard of one popping out!

In my book ... this is NOT PLACING FOOLISH BLINDNESS in an anchor ... anything but!

We all know avb3 intentions in previous Rocna blogs and I smell the intentions of others to bring disrepute to Rocna ... aint gonna happen that easy ... not as long as my Rocna keeps digging in day after day without so much as a mishap! I just don't buy this stuff and would not be surprised if JoJo has his own hidden agenda here!

NOW .. if one of you 'technical anchor know all's' would make a comment such as ... 'in the old days Rocna 25kg would hold a mass of x tons' but due to new steel grades todays Rocna requires a 33kg for the same tonnage ... yeah ... I would listen to that! But instead all we have are 'Trolls' (people who discredit a product for their own purposes) bringing the ENTIRE product to it's knees.

Happily, there are still a number of serious sailors out here who see right through it all ... I am one of them!
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Old 30-07-2012, 12:50   #54
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Re: Well Done Rocna

JonJo,

Wikipedia is your friend! Find out all about "trolls" here: Troll (Internet) - Wikipedia, the free encyclopedia)
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Old 30-07-2012, 12:54   #55
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Re: Well Done Rocna

What I find interesting on these posts, is the PROFILES of the individuals who continuously post negative comments have nothing worth seeing under 'about me' ... but if one looks at JonJo for example ... joined in 2011 ... see posts or threads ... just about all are to do with Rocna.
I may have retired to sailing, but I had enough businesses and more than enough experience to see where this is all coming from!

We cruisers want to go on sailors experiences ... wont buy into this crap!
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Old 30-07-2012, 13:00   #56
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Re: Well Done Rocna

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JonJo,

Wikipedia is your friend! Find out all about "trolls" here: Troll (Internet) - Wikipedia, the free encyclopedia)
Good one Videobear ... will have to watch my response to 'trolls' as I'm afraid I may have become one.

I just hope that serious people cruising out there with their families don't buy into these guys. We have a mate sailing a very similar boat to ours and currently in the USVI's ... nearly 'came unstuck' a number of times on his anchor with his entire family on board. In Fortaleza, their 'then anchor' dragged and damaged the vessel without them having seen the cracks ... vessel almost sank at sea.

I convinced him to buy the same anchor we have and he has NEVER BEEN HAPPIER saying it is incredible to have the holding they now enjoy.

Wont mention the other brand of anchor as suffice to say, if cruisers have drama with their anchors, they can feel safe on a number of others INCLUDING Rocna!

This ... from EXPERIENCE!
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Old 30-07-2012, 13:17   #57
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Re: Well Done Rocna

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Originally Posted by impi View Post
What your photo neglects to show is the size of the anchor for the weight of the particular vessel ... I go on the fact that I live on my anchor every day and have anchored every day in various parts of the world ... would not change my Rocna out for any other based on my experience of what it has done for me in conditions where other boats dragged and broke loose. One thing about Rocna ... may have had undersized (for the job) shanks bend but never heard of one popping out!

In my book ... this is NOT PLACING FOOLISH BLINDNESS in an anchor ... anything but!

We all know avb3 intentions in previous Rocna blogs and I smell the intentions of others to bring disrepute to Rocna ... aint gonna happen that easy ... not as long as my Rocna keeps digging in day after day without so much as a mishap! I just don't buy this stuff and would not be surprised if JoJo has his own hidden agenda here!

NOW .. if one of you 'technical anchor know all's' would make a comment such as ... 'in the old days Rocna 25kg would hold a mass of x tons' but due to new steel grades todays Rocna requires a 33kg for the same tonnage ... yeah ... I would listen to that! But instead all we have are 'Trolls' (people who discredit a product for their own purposes) bringing the ENTIRE product to it's knees.

Happily, there are still a number of serious sailors out here who see right through it all ... I am one of them!
My intentions in previous Rocna threads was to bring to light the deceit that the previous owners performed in pretending that they were producing an anchor to one specification, when in fact it was produced to a much lower specification.

The previous owners also were at best economical with the truth on RINA certification.

CMP builds good chain. It is disappointing that they are now building Rocna anchors to a lower specification then Peter Smith originally called for. In fact, Peter insisted that the anchor required his original specifications to work properly.

Now, he apparently is OK with the new, lower steel specifications. Why? That has not been explained clearly.

I do not understand why CMP is not producing to the original specs. The NZ and Canadian built Rocnas are some of the best anchors around. Great design, and built to a spec that is unquestioned. Anything that came afterwards is suspect.

So, AVB3 has no agenda except requiring clarity and the truth.

That is not too much to ask, is it?
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Old 30-07-2012, 13:36   #58
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Re: Well Done Rocna

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My intentions in previous Rocna threads was to bring to light the deceit that the previous owners performed in pretending that they were producing an anchor to one specification, when in fact it was produced to a much lower specification.

The previous owners also were at best economical with the truth on RINA certification.

CMP builds good chain. It is disappointing that they are now building Rocna anchors to a lower specification then Peter Smith originally called for. In fact, Peter insisted that the anchor required his original specifications to work properly.

Now, he apparently is OK with the new, lower steel specifications. Why? That has not been explained clearly.

I do not understand why CMP is not producing to the original specs. The NZ and Canadian built Rocnas are some of the best anchors around. Great design, and built to a spec that is unquestioned. Anything that came afterwards is suspect.

So, AVB3 has no agenda except requiring clarity and the truth.

That is not too much to ask, is it?
Did you ever work for Rocna?
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Old 30-07-2012, 13:39   #59
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Re: Well Done Rocna

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Originally Posted by impi View Post
What your photo neglects to show is the size of the anchor for the weight of the particular vessel ... I go on the fact that I live on my anchor every day and have anchored every day in various parts of the world ... would not change my Rocna out for any other based on my experience of what it has done for me in conditions where other boats dragged and broke loose. One thing about Rocna ... may have had undersized (for the job) shanks bend but never heard of one popping out!

In my book ... this is NOT PLACING FOOLISH BLINDNESS in an anchor ... anything but!

We all know avb3 intentions in previous Rocna blogs and I smell the intentions of others to bring disrepute to Rocna ... aint gonna happen that easy ... not as long as my Rocna keeps digging in day after day without so much as a mishap! I just don't buy this stuff and would not be surprised if JoJo has his own hidden agenda here!

NOW .. if one of you 'technical anchor know all's' would make a comment such as ... 'in the old days Rocna 25kg would hold a mass of x tons' but due to new steel grades todays Rocna requires a 33kg for the same tonnage ... yeah ... I would listen to that! But instead all we have are 'Trolls' (people who discredit a product for their own purposes) bringing the ENTIRE product to it's knees.

Happily, there are still a number of serious sailors out here who see right through it all ... I am one of them!

That anchor is the very well know Venice Anchor. The specs of the anchor, boat, rode and conditions are quite well documented. (it is not my photo by the way)

As for your anchor, rode, boat combination it appears that you have an extensive history with them and they have earned your trust. Why would you force that trust on others (and other combinations)?

You have a vested interest in your anchor. That is fine. I owned a Rocna once and returned it. I found that I had doubts in the anchor that I could not live with. Others may or may not have doubts. We should let others choose freely after listening to many views.

Speaking of your anchor, where and when was it built? What size is it.

I do hope that you can refrain from making this a personal attack on me or on others. It appears that you have strong opinions - perhaps others do also.

I can't speak for the others (ABV3, JOJO etc) but I do not have an agenda (hidden or otherwise). I do have doubts about the initial few years of China made Rocnas and lesser doubts about the current China made Rocna. I would truely love to have a 33 or 40 Kg NZ or Canada Rocna.

Speaking of agendas, it appears to Me that You have an agenda. It appears to me that your agenda is to shut up people who do not trust Rocna. I could be wrong.

Let me ask a question: Would you trust one of the sub 400 MPa steel rocna anchors on your boat adverse conditions? One like the Venice anchor?

Regards!
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Old 30-07-2012, 13:52   #60
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Re: Well Done Rocna

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That anchor is the very well know Venice Anchor. The specs of the anchor, boat, rode and conditions are quite well documented. (it is not my photo by the way)

As for your anchor, rode, boat combination it appears that you have an extensive history with them and they have earned your trust. Why would you force that trust on others (and other combinations)?

You have a vested interest in your anchor. That is fine. I owned a Rocna once and returned it. I found that I had doubts in the anchor that I could not live with. Others may or may not have doubts. We should let others choose freely after listening to many views.

Speaking of your anchor, where and when was it built? What size is it.

I do hope that you can refrain from making this a personal attack on me or on others. It appears that you have strong opinions - perhaps others do also.

I can't speak for the others (ABV3, JOJO etc) but I do not have an agenda (hidden or otherwise). I do have doubts about the initial few years of China made Rocnas and lesser doubts about the current China made Rocna. I would truely love to have a 33 or 40 Kg NZ or Canada Rocna.

Speaking of agendas, it appears to Me that You have an agenda. It appears to me that your agenda is to shut up people who do not trust Rocna. I could be wrong.

Let me ask a question: Would you trust one of the sub 400 MPa steel rocna anchors on your boat adverse conditions? One like the Venice anchor?

Regards!
To the contrary I really respected your input and when I looked at your profile I could quickly see who it was I was talking to.

My only agenda since I am retired is to enjoy my life at sea and being part of a forum with other cruisers means I can defend products under attack that I have discovered to be an enhancement to our safety.

Possibly my 'strong opinion' on this matter is the amount of time I spent checking my Rocna night after night where Ana and I were so afraid something may go wrong .... all because some clowns 'with hidden agendas' were making a meal out of 'Rocnas fall'.

Of course our experience has been somewhat different and so I am pretty passionate about challenging people who made us feel this way in the previous Rocna forums.

One post from me there will show that I was fearful of the fact (at the time) I had purchased one of these ... suffice to say it has been a SPECTACULAR anchor, not only for us but a number of fellow cruisers out here!

My Rocna is a chinese brand 33Kg purchased ... hmmm... I would guess around 2 years ago ...

Trust the anchor ... I am not an expert on steel but know enough to know I would rather have a shank bend than snap ... been in some pretty stormy seas as mentioned before ... my Rocna has done neither ..

Anyone know of someone who has lost their boat due to a Rocna failure?
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