Anchors and anchoring


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Simon Currin
Simon Currin
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It's always entertaining when someone poses an anchoring question. I just lifted this thread from the OCC Forum. All very topical as earlier this month we were rafted up with Peter Smith in Nuuk who invented both the Rocna and the Vulcan.
Hello
We are in the market for a new main bow anchor and would like to ask the OCC comunity if anyone has any experience in the Vulcan anchor (made by Rocna). Pros and Cons?
We currently have a 20 kg Delta which we are very pleased with but it has been a bit beaten up.
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Whoa!! The start of an anchoring thread!!! Lookout for LOTs of opinions![/font]

Personally like both the Spade and the Rocna - but don't know the Vul[font=inherit]

[font=inherit][font=inherit]We have been using the Vulcan for 2 years now, picked it because no roll bar interface issue with our bow sprit. Deploys real nice and sets very quickly. Have had no holding issues with it in two years of use, including switching currents. If you an[/font][/font][/font]

[font=inherit]Further, we find setting and holding performance same as the Rocna.[/font]



[font=inherit][font=inherit][font=inherit]Just deployed my rocna for first time. Set instantly. Brilliant. My old 20kg Bruce would drag all over the bay before sort of setting. [/font]
[font=inherit]The rocna chart said I needed the 33kg version but this is massive and over sized. I got the 25kg instead and it’s a beast. Best insurance money I’ve spent. In my humble opinion [/font][/font][/font]

[font=inherit][font=inherit]Had you considered getting another Delta but bugger?Our 40kg is very good[/font][/font]

[font=inherit]Yes I have. Our 20 kg Delta on 37 feet boat has never let us down when set. But it struggles to set or not at all in very soft mud. There I figured the Vulcan would be better?[/font]

[font=inherit]Or a bigger Delta[/font]

[font=inherit]Rocna 33 has never let us down even in quite challenging conditions. Only issue is the amount of mud it brings up![/font]

[font=inherit]My concern about the concave anchors is just that and that they have reported problems on resetting after a wind shift due to the collection of material on the surface. See reports on Morganscloude.[/font]

[font=inherit]I understand that the Vulcan is the same as the Rocna apart from the the omission of the roll bar. Apparently the roll bar was omitted to it easier to stow on motor boats.[/font]
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[font=inherit]I have a Rocna 20 kg on a Tradewind 35 and it just works, only trouble I've had is among heavy weed growth in NW Spain.[/font]
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[/font][font=inherit][font=inherit][font=inherit][font=inherit][font=inherit]I vote for the Knox-anchor. We have the 27 kg and never have had any problems with setting.[/font][/font][/font][/font][/font]http://www.knoxanchors.co

[font=inherit]Well the split fluke is a no no for me. That's a chain catcher in wind shifts. Like a Danforth. I've seen it happen and it's a nightmare.[/font]


[font=inherit]I don't like Danforths either but this is a very different design.[/font]

[font=inherit]Good experience with using a Rocna Vulcan in the Chesapeake Bay's sand and soft mud. One size less than recommended, but sets well and holds fast--including through shifts of direction.[/font]

[font=inherit]Good info. The Chesapeake is mostly soft muddy bottom I understand and that's where our Delta is not doing well.[/font]

[font=inherit][font=inherit]How big is your boat? What area do you cruise? If you are usually in rock, or kelp, or sand, etc, different anchors would be better.[/font]

[/font][font=inherit][font=inherit]We cruise worldwide. Our boat is 37 feet.[/font]
www.syseawind.blogspot.se
www.facebook.com/syseawind[/font][font=inherit]Manage[/font]
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[/font][font=inherit][font=inherit]SYSEAWIND.BLOGSPOT.COM[/font]
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[font=inherit]I tend to prefer proven anchors. The Manson and Rocna seem to be popular. I still have my Genuine CQR, but, I will be getting a Manson or Rocna, I think. I was disappointed in the galvanize quality on a Manson here in the marina. I need to aske them about that.[/font]

[font=inherit]Why change? I have delta also .Have sailed anchored more than most worldwide[/font]

[font=inherit]Good question. I'm not so sure I will.[/font]

[font=inherit][font=inherit]We love our Rocna 51. Drop it and forget it (almost). Manson supreme are also good. (Get one a size larger than the website recommends. Bigger is better.)[/font]
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[/font][font=inherit][font=inherit]Been let down twice by the Delta so changed to Manson Supreme - brilliant. Had to modify bowsprit to accommodate the roll bar but all good. Thank you for starting an anchor thread - ages since I've been on one .....[/font]

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[font=inherit]The Rocna 33 sits comfortably on the bow of our Island Packet[/font]

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[font=inherit]For your boat maybe better a Rocna 33 ? ! Regards[/font]

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[font=inherit]I don't like the roll bar and reported problems with resetting in sudden wind shifts.[/font]

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[font=inherit][font=inherit]Interesting thread. We have had great service from our Delta and have chosen this again on new boat. We also vote for using a chum weight.[/font]

[/font][font=inherit][font=inherit]Suggest reading Eric Hiscock ' Come aboard '. Very good description of anchors and setting of them which is still contemporary.[/font]

[/font][font=inherit][font=inherit][font=inherit]The best book I have read on anchoring is this one. Written by a man who designed anchoring systems for science buoys. Ask your local library if they can get it for you through Interlibrary Loan.[/font]

https://www.goodreads.com/.../2340300.Oceanography_and...[/font][font=inherit]Manage[/font]

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GOODREADS.COM
[/font][font=inherit][font=inherit]Oceanography and Seamanship[/font]
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[font=inherit][font=inherit]It is a great book. His theory on optimal rides has proven well in practice. We sat through a cat 4 hurricane and a cat 2 one using his theory[/font]
[font=inherit]I bought the book in the 70’s. Unless it has been updated Roxana etc are absent[/font][/font]

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[font=inherit]FYI There are some good anchoring discussions on the OCC Forum - and unlike Facebook, they're archivable for future reference...[/font]
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[font=inherit]Just changed from a 30 kg Bruce to a 33 kg Vulcan. Holding is great in both, but Vulcan sets more easily, and penetrates harder bottoms.[/font]
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[font=inherit]The Vulcan is made by Rocna. Its shank shape was developed to more easily fit on power boats. We have tested it alongside the Rocna and Ultra and found its performance to be equivalent to those newer generation anchors. We still like the Ultra best, but its expense is a factor.[/font]
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[font=inherit]Actually shank shape was designed to contribute to roll into optimal setting position, that coupled with weighted shoe result in proper orientation without a roll bar. The upside is that the shank shape means it self deploys easier.[/font]
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[font=inherit][font=inherit]Just a general comment regarding this anchor thing. How quick it sets, one or two anchor lengths, doesn't matter as long as it sets properly. Holding power is important and should match your boat size. A good size CQR holds well enough while set. In my[/font][/font][font=inherit][font=inherit][font=inherit] opinion the most important criteria is how well it handels a sudden 180 wind shift. That's what gives you peace of mind. Knowing your anchors weaknesses is important. The only Delta weaknesses in my experience is in soft mud.[/font][/font][/font]
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[font=inherit]Delta is a plow. All plow anchors have have the same weakness that in surge conditions they will actually plow through the bottom. Conversly 3rd gen concave anchors will attempt to dig in deeper.[/font]
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[font=inherit][font=inherit]Well it's a common missconception that a plow anchor is the same as a farmers plow. Which only has one side to turn the ground upside down. A Delta or a CQR is more like chisel that digs down the harder you pull. Sometimes my Delta is so deep down I have to run over it to get it back on board.[/font][/font]
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[font=inherit]Well in Marsh and Blackpoint have seen furrows after a blow from CQR and Deltas. So my comment based on my eyeball.[/font]

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[font=inherit]What is Marsh and Blackpoint? Sorry for my lack of English vocabulary.[/font]
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[font=inherit][font=inherit][font=inherit][font=inherit][font=inherit][font=inherit] our experiance with our CQR was not great. Various places in Chesapeake, ICW and Bahamas we had periodic issues with setting, and dragging. We never had a good sleep. Once we traded for a Rocna saw a noticable difference in both settin[/font][/font]…See more[/font][/font][/font][/font]

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[font=inherit]Both are popular anchorages in the Bahamas.[/font]
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[font=inherit]How quickly the anchor sets is very important if you are in a crowded anchorage ... and frequently one is in a crowded anchorage.[/font]
edited by simoncurrin on 8/3/2018
bwallace
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Hi all, not sure where this post should be but I am sure it will eventually end up in the correct (bin)?

In last month e bulletin, there was an article entitled “why no one cares about yours travels”. I agree with what has been written, as we find the same.

My thought is can someone do a study or has a study been done to understand why when anchored in quiet anchorage, another boat comes in and 90% of the time wants to anchor near you? we can be in a large bay with plenty of room for safe anchoring and peace and quiet. But no we seem to be a magnet.
I know we are not alone in this quandary, so maybe someone has looked into the minds of these types of sailors

We are reasonably sociable folks, but can never stop wondering what are these people thinking about. Amazingly we came across one boat that it turned out were fairly well healed, lived in a large private’s residence, so you would think they would enjoy some space, No, they did not seem to take the hint to move further away.

I know we all have examples, and there are some deterrents you may use which again may make interesting reading!

Sail Safe

Brian and Sue
S/V Darramy anchored in a quite bay in the Peloponnisos 😎
Dick
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bwallace - 7/10/2019
Hi all, not sure where this post should be but I am sure it will eventually end up in the correct (bin)?In last month e bulletin, there was an article entitled “why no one cares about yours travels”. I agree with what has been written, as we find the same.My thought is can someone do a study or has a study been done to understand why when anchored in quiet anchorage, another boat comes in and 90% of the time wants to anchor near you? we can be in a large bay with plenty of room for safe anchoring and peace and quiet. But no we seem to be a magnet. I know we are not alone in this quandary, so maybe someone has looked into the minds of these types of sailorsWe are reasonably sociable folks, but can never stop wondering what are these people thinking about. Amazingly we came across one boat that it turned out were fairly well healed, lived in a large private’s residence, so you would think they would enjoy some space, No, they did not seem to take the hint to move further away.I know we all have examples, and there are some deterrents you may use which again may make interesting reading!Sail SafeBrian and SueS/V Darramy anchored in a quite bay in the Peloponnisos 😎

Hi Brian & Sue, Never underestimate the herding instinct. Dick Stevenson, s/v Alchemy
David.Frost
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We aboard Taipan have just been through a mini anchor drama. Having lived aboard and anchored around the world in over 1000 different anchorages during the past 18 years we were in total shock when our trusty Rodolfo "Other Type" disappeared off the bow as we retrieved it. The cause of this disaster was a 2-year-old S/S  Swivel. The 15mm pin connecting the two rings sheared. Oxygen deprivation corrosion. David had the gear on the ground a month before when we hauled out, inspected it closely and rewired all the shackles after inspection. It was not detectable. We were lucky as this failure could have been very dramatic in the middle of the night in a big blow. Lesson. No more swivel. We had to replace the anchor, at considerable expense here in Panama. We purchased a Rocna 40. This required only a minor bow roller modification. 
We hope to go back to the site off Panama and dive for Rodolfo. That anchor was 55kg. We are 50ft and now we are so overloaded with stuff after 18 years I hate to think what we weigh... but it's over 20 ton. Our chain is 10mm short link galvanised and is now 6 years old. Rodolfo was built (and signed) in Fremantle Australia, by an old fisherman and we purchased it second hand for $60. It doesn't owe us anything, It has never dragged but we did have to upgrade our windlass!!!
No more swivels on Taipan.

Dick
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David.Frost - 7/20/2019
We aboard Taipan have just been through a mini anchor drama. Having lived aboard and anchored around the world in over 1000 different anchorages during the past 18 years we were in total shock when our trusty Rodolfo "Other Type" disappeared off the bow as we retrieved it. The cause of this disaster was a 2-year-old S/S  Swivel. The 15mm pin connecting the two rings sheared. Oxygen deprivation corrosion. David had the gear on the ground a month before when we hauled out, inspected it closely and rewired all the shackles after inspection. It was not detectable. We were lucky as this failure could have been very dramatic in the middle of the night in a big blow. Lesson. No more swivel. We had to replace the anchor, at considerable expense here in Panama. We purchased a Rocna 40. This required only a minor bow roller modification. 
We hope to go back to the site off Panama and dive for Rodolfo. That anchor was 55kg. We are 50ft and now we are so overloaded with stuff after 18 years I hate to think what we weigh... but it's over 20 ton. Our chain is 10mm short link galvanised and is now 6 years old. Rodolfo was built (and signed) in Fremantle Australia, by an old fisherman and we purchased it second hand for $60. It doesn't owe us anything, It has never dragged but we did have to upgrade our windlass!!!
No more swivels on Taipan.

Hi David,
It is good to hear field reports such as yours; to often we remain silent about things that do not go well. I have long contended that swivels are not necessary on cruising boats (and are often the weak link) and that stainless steel has no place at all in a ground tackle system.
I am sorry this happened to you but appreciate the report and are glad the discovery was not more painful than a lost anchor.
I very much support your conclusion.
My best, Dick Stevenson, s/v Alchemy

bwallace
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Hi David,
Thanks for the report, And glad all turned out safely for all concerned, and hope Rodolfo eventually is recovered.

My request is can I forward your report to Vyv Cox, a specialists Metalurgy scientist, who writes for Yachting Monthly and is a friend of mine.

I await your reply

Brian and Sue
S/V Darramy in the Peloponnisos
David.Frost
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bwallace - 7/21/2019
Hi David,
Thanks for the report, And glad all turned out safely for all concerned, and hope Rodolfo eventually is recovered.

My request is can I forward your report to Vyv Cox, a specialists Metalurgy scientist, who writes for Yachting Monthly and is a friend of mine.

I await your reply

Brian and Sue
S/V Darramy in the Peloponnisos

Hi Brian and Sue. That would be fine and I also have photos of the offending swivel.... well what's left of it.  

bwallace
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Hi David,
Vyv has responded and asked for the photos, can you send to my e mail one.23@virgin.net

I am hoping he may be able to offer technical expertise which may be useful to other members on the forum.

I see you are from Australia. We had18 months on the East Coast and a fair bit of land travelling also. We loved the place.

Our time Panama was enjoyable as well.

Cheers

Brian the Pom!


bwallace
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Here is the reply I have received from Vyv Cox. David’s Photos helped with the diagnosis of the failure.

Reply:
Hi Brian,

Here is my response. Thanks for the opportunity to contribute. Please pass it on to your forum.

Best regards

Vyv

Failed bolt-type swivel ex SV Taipan

I suggest you refer to the page of my website that deals with connectors, http://coxeng.co.uk/anchoring/connectors/ but also other pages, particularly under Metallurgy.

The type of swivel used by Taipan is probably the worst that can be selected. I believe that most of this type are manufactured in Spain for the fishing industry and realistically should never be used for yacht anchoring. Not only does its axial strength depend upon a nut and bolt in tension, mechanically a very poor situation, but also it has very limited articulation in certain attitudes. I suspect that this has been a contributory factor in the failure. It can truly be said that in this case the swivel was the weakest link but others, particularly Kong, can be 1.5 times stronger than the chain.

Bolts almost always fail at the first turn inside the nut, as this is the point of maximum stress. In particular, fatigue failures in bolting are absolutely characterised by this failure mode, examples on the website. The Taipan failure has clearly suffered additional corrosion damage, which might suggest the failure mechanism to be corrosion fatigue. However, I suspect the actual cause to be stress-corrosion cracking (SCC), covered in detail on my website. The rough surface of the fracture face is typical of branched cracking rather than the single crack of fatigue. The temperature requirement for SCC is around 60 degrees C, easily achieved by deck fittings in warm sunny climates. Stress is clearly going to be high and concentrated at thread roots, with the additional effect of bending due to the poor articulation.

Stainless steel is a poor choice for moorings, where a shackle or other component may be immersed permanently in mud. However there are many cases, e.g. propeller shafts, folding and feathering propeller pins, where stainless steel under water is reliable and lasts for many years. My Kong swivel and Wichard shackle, both stainless steel, have been in anchoring service since 2005, anchoring for half of every year in the Mediterranean. Regular inspection is advised.

Some anchoring arrangements work well without swivels, in which case there is absolutely no need to fit one. We find a swivel brings handling benefits and after a trial season without one we made the decision to revert to using it. My website shows the method I developed and found most useful, with three links of chain between the swivel and the anchor. This has been widely adopted and is recommended by many anchoring experts.

Vyv Cox. engineer33@btinternet.com

David.Frost
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Thankyou for your advice and I hope many more sailors out there will read this
Best regards
GO

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