Rocna Anchor

[demonboy]

As regular forumites will know there is one subject that will rouse more furious debate than any other subject known to man, beast or Poseidon: anchors. The simple anchor is the one thing on our boat we need to trust more than anything else (except perhaps our vessel's ability to keep water out) so it is little wonder this forum witnesses grown men pull each others' hair out when arguing which anchor is best. We thought we'd pour some fuel on the debate.

We had a bit of cash to spend on an anchor last year and, after pulling some hair, making some enemies and speaking to the YBW forum elders, we opted for a Rocna. We promised its designer, Craig Rocna, to return an unambiguous account of our experience with his design, should we write an article for followtheboat. He was happy for us to do this but I must emphasise that he said explicitly “be honest”.

You know us, Craig, a Spade's a Spade...

Click here to read our initial thoughts. At the end of the article is the option to add your own comments/abuse. Feel free to do so!

 

[[2574]]

Interesting.

I've swapped a Bruce 20kg for a Rocna 20. I've used the anchor once about two weeks ago at Cawsand bay, Plymouth.

I was expecting great things but I can only report that my first ever experience was not good - I dragged the Rocna around the bay. We were in 8m of water and i'd laid 25m of 10mm chain. I gave up and relaid but this time used "the cup of tea method" of laying the chain (see another thread hereabouts on technique) and it seemed to settle okay. We spent the night on it and didn't move. When we pulled it up the mud/sand mix of Cawsand appreared to have had covered only about two thirds of the anchor shoe so i'm thinking that the anchor didn't bury itself overnight. We had light breezes so no real test for the anchor - more technique practice needed. If anyone can offer guidance on how they lay out their Rocna then I'm all ears........

rob

 

[demonboy]

Sorry, I didn't start this thread to add to the plethora of threads on anchors and anchoring, it was merely to point you to our account of the Rocna. I have touched on our technique in the article.

I would suggest from what you describe Robih that it is your technique that is at fault, not the anchor. I've written about our technique before on this forum so do a search first. If you can't find it then PM me and I'll tell you about my technique. It works for me.

 

[Anonymous]

We've never had any problems in Cawsand Bay with a Danforth or a Bruce. Holding is quite good and the RN know (often anchor alongside them).

 

[[2574]]

Yes our Bruce was always quick to bite at Cawsand so I've no doubt that I just need to learn some technique to layout the Rocna. Here's hoping anyway.

I've seen a while ago a comment from you that you couldn't fit a Rocna without extensive modifications to the roller on your N42. I've had a roller made for our N39 and found it a very good arrangement - I'll send some photo's to Craig at Rocna for him to add to the knowledge base so in due course you can have a look if it is of interest.

rob

 

[Anonymous]

[ QUOTE ]
Yes our Bruce was always quick to bite at Cawsand so I've no doubt that I just need to learn some technique to layout the Rocna. Here's hoping anyway.

I've seen a while ago a comment from you that you couldn't fit a Rocna without extensive modifications to the roller on your N42. I've had a roller made for our N39 and found it a very good arrangement - I'll send some photo's to Craig at Rocna for him to add to the knowledge base so in due course you can have a look if it is of interest.

[/ QUOTE ]Yes, I had to get rid of the Bruce as it doesn't work well in much of the W Med unless you sharpen it with an angle grinder. I was going to buy a Rocna and then went for a Delta instead...not being negative about the Rocna, I have no experience of them.

We are happy with the Delta and I won't change now. As a second/kedge I swear by the Danforth design or Fortress. They really do pierce the weed and hard sand.

Incredible that the Rocna should do badly at Cawsand....the sales talk is about just letting it go and waiting for a massive pull. Would be interesting to hear back from Craig or others, on that.

 

[charles_reed]

The only reservation I have about the Rocna is the tremendous premium you have to pay for the roll-over bar, compared to the well-established and tested Bugel.

Whatever the anchor that fades into insignificance compared to 1) choice of bottom and 2) technique. IMHO of course.

 

[Anonymous]

Whatever the bottom or the anchor, you do need to be able to motor back on it with a fair bit of welly and not drag, otherwise you are not 'anchored' in any meaningful sense of the word. In some bottoms I give it half an hour before going hard astern; just tug it back to set it, then leave it, before re-starting the engine and checking it properly.

 

[MacMan]

We anchored a few times in Cawsand with our Spade - no problems. No real technique needed. Just lob it over it sticks - first time - nearly every time with 3 months at anchor last year. I was wondering if the Rocna was better than our Spade but perhaps not. And would be interested to hear if anyone has could explain the difficulties with a Rocna at Cawsand.

 

[rivonia]

Hi where did you get the anchor testing report/results from? My question to you is because I cannot agree with it, due to the fact tha the Fortress has had many tests over the years and come out on top. According to the US coast guard it is THE BEST anchor.

 

[craigsmith]

[ QUOTE ]
We were in 8m of water and i'd laid 25m of 10mm chain. I gave up and relaid but this time used "the cup of tea method" of laying the chain (see another thread hereabouts on technique) and it seemed to settle okay. We spent the night on it and didn't move. When we pulled it up the mud/sand mix of Cawsand appreared to have had covered only about two thirds of the anchor shoe so i'm thinking that the anchor didn't bury itself overnight. We had light breezes so no real test for the anchor - more technique practice needed. If anyone can offer guidance on how they lay out their Rocna then I'm all ears........

[/ QUOTE ]
Rob from the above the most obvious issue to see is that you mention 25m of rode in 8m of water, which corresponds to let's say 9m distance between the sea-bed and the roller. That's a scope ratio of less than 2.8:1, and that's assuming the 25m figure is accurately measured.

The Rocna will handle short scope very well, relative to other anchors, but setting it at such a low scope will be difficult, especially if you put too much force on it. What happens is the anchor starts to bite, and even the tip area of the fluke can provide quite a lot of (horizontal) resistance. This then starts to straighten the chain, whereupon a lot of vertical force is put on the anchor - before it's properly set. If the anchor isn't set, the only thing that's stopping it lifting off the sea-bed is its own weight (trivial in context).

This is a common problem in very difficult sea-beds, but applies to any if the scope is too low and too much "back-down" force is used. An article on the Rocna Knowledge Base about setting and retrieval touches on this.

In any case, with any temporary drag embedment anchor (what we all use), decent scope is mandatory, and that applies to the Rocna too.

 

[craigsmith]

[ QUOTE ]
We promised its designer, Craig Rocna, to return an unambiguous account of our experience with his design, should we write an article for followtheboat. He was happy for us to do this but I must emphasise that he said explicitly “be honest”.

[/ QUOTE ]
Hey just one correction, I'd like to take the credit but I'm not the designer - Peter is! /forums/images/graemlins/ooo.gif

 

[demonboy]

Fidelis,

You are falling into the trap of turning this thread into a hair-pulling contest. The original post was to direct you to an article on our experience with our new Rocna compared to the CQR. Noting to do with Fortress.

The article, btw, comes from Sail magazine I believe.

 

[demonboy]

Er, yes, I knew that Craig. Ahem. /forums/images/graemlins/blush.gif

 

[Anonymous]

[ QUOTE ]
The article, btw, comes from Sail magazine I believe.

[/ QUOTE ]Yes, but that article has been challenged many times, over many years, on this forum, by anchor designers.

 

[demonboy]

Of course it has! I wouldn't expect anything less of this forum /forums/images/graemlins/wink.gif

 

[Anonymous]

[ QUOTE ]
Of course it has! I wouldn't expect anything less of this forum /forums/images/graemlins/wink.gif

[/ QUOTE ]But surely when technical data has been questioned so many times by people in the business, it is best to make that clear? Especially when it is being produced, yet again, as a commercial endorsement of a poster's own product? /forums/images/graemlins/smile.gif

 

[demonboy]

[ QUOTE ]
...by people in the business

[/ QUOTE ]

The real people in the business are yotties like you and me, David, who are actually using the anchor in real-life, day-to-day situations, dropping and weighing it many times in a month, not people who kick and scream and shout in internet forums arguing the toss over charts.

The fact is I have a Rocna and it works far better than my CQR. So far I'm happy with it and that chart contributed towards my successful purchase decision.

 

[Anonymous]

[ QUOTE ]

The real people in the business are yotties like you and me, David, who are actually using the anchor in real-life, day-to-day situations, dropping and weighing it many times in a month

[/ QUOTE ]Jamie, I agree. I wasn't taking issue with your opinion and experience, only the re-publication of a very old and dubious test /forums/images/graemlins/wink.gif

 

[demonboy]

Furry muff.