Anchoring techniques

[craigsmith]

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---- said on these forums a number of times: tandem anchoring cannot be relied upon.

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In total agreement : it is a relic of the days when the fisherman type was the norm, but I came across it again in a relatively recent book by a French 'expert' on anchoring.
As a result, and faced with staying in a Hebridean anchorage with ''F10, perhaps F11'' forecast for the area, I shackled my twin CQRs in tandem for the first (and last) time. At the height of the storm we were suddenly on our way to open water, with a lee behind Cape Wrath as our most likely salvation. Thanks to an anchor watch and a quick-starting engine, we got the ironmongery up before being driven into the big stuff roaring past the point half a cable away. We removed the second anchor and relaid the first, which then held hard in its usual exemplary fashion.
A few moments thought, and all became clear: an anchor designed to bury deep is inhibited by shackling anything to it: Tandem ? NEVER AGAIN!

[/ QUOTE ]You might also say you must avoid shackling the rode to the anchor, lest it prevent it burying...

Or perhaps your CQRs were set up in a similar fashion to that of the anchors of the skipper in this MAIB case study. No doubt he has been scared off using tandems too!

No slight intended, but you do not give details (you shackled the tandem to the trip-eye of the primary? that is incorrect!). If anything is learned by people reading this thread, it should be that tandem anchoring is a complex thing, and the theory must be properly understood, else it can do more harm than good.

It is the poor tradesman who blames his tools (or in this case, how they are set-up).

 

[duncan]

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The trip-line of the Delta is NOT designed for a tandem anchor and is the WRONG place to attach its rode - this will have unbalanced the Delta, and is the mostly likely cause of the system failure, since the Bruce on its own is far too small to be effective

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I was about to chastise you Craig for having the anchors the wrong way round but, 'cos you wouldn't make such an elementary mistake, rechecked the article to find that the words and pictures don't match!

As my original thoughts went along the lines of the boat having been anchored to the set bruce but without the delta being in play at all (possible from picture) I am now with you and agree that with both set the bruce could prevent the delta responding correctly to the veer as they were rigged (according to the words).

 

[graham]

Re: Tandem set technique

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Absolutely not, that is a logical fallacy. If both anchors have dragged far enough that the tandem has entered the trough of the primary, you have problems in any case.

Furthermore entering another anchor's drag trough often allows the anchor to bury more deeply. It is not a bad thing per se. We have seen this frequently in testing.

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That also makes sense but leaves me with a bit of a dillema.

I do try to keep an open mind to new ideas but how do I decide which of you experts (Craig/Hylas) should be listened too?

your experiments seem to have left you completely at odds on this.

 

[craigsmith]

Re: Tandem set technique

Give me the opportunity and I will be extremely critical of Hylas's "experiments"; it seems clear to us that he himself does not understand the theories entirely and is not giving the technique a fair chance. His experiments are valid only in that they prove that tandem anchoring will give you problems if it is not done properly. Many of the comments he makes in his cut-and-pasted post above (the long one) are utter nonsense.

However, we also dislike recommending tandem anchoring. It seems a popular topic, especially recently on this board, but is a method that should almost never have to be used. Your primary anchor and rode should be sized to handle 99% of all scenarios. If it is not, the solution is not to go adding complexity to the system with dual anchors etc - it is to fix the current problem (i.e. upgrade).

I suggest that if you do intend to use tandems, you
1) learn all the theory as best you can from people like us
and
2) practise deployment, setting, and retrieval in managable conditions before having to depend upon it.

 

[duncan]

Re: Tandem set technique

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your experiments seem to have left you completely at odds on this

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I don't see them as completely at odds...........on another thread hylas agreed that if you had 2 anchors on board, the same size and pattern, and were able to check they were both set, anticipated a constant prolonged direction of wind then putting a good gap between them etc (to give each clean ground) was sensible and that you could expect better holding from the pair than a single BUT generally it should be avoided and you should be able to ride to a single appropriate bower anchor. If constant veering was anticipated to be a problem setting the 2 at 60 degrees on seperate rodes has been suggested as the better solution by both too if my memory serves. I believe Craig agrees that complications such as tandem set up's are best avoided as well butif you are going to do it then................

Overall I remain convinced that it they both wrote definitive books on anchoring techniques they would agree 98% - it's just that in choosing which element of a post to respond to in a thread they end up presenting apparantly differing perspectives!

 

[graham]

Re: Tandem set technique

I think that inevitably different experts will not agree on everything but basically both of you seem to concur that one decent anchor is the better option rather than a tandem set up.

 

[hylass]

Re: Tandem set technique

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I think that inevitably different experts will not agree on everything but basically both of you seem to concur that one decent anchor is the better option rather than a tandem set up.

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This is very common everywhere.

Then you have several "expert" opinions:

- Hylas - designer of the Spade anchor and author of a book about anchors and anchoring.. AGAINST it

Jean Louis GOLDSHMID - Former Technical Director of "les Glenans" the most prestigious French sailing school- AGAINST it

Craig Smith: ?????? FOR it (but admitting this is a rather cemplicated technique)

This would help you to make your own opinion!... /forums/images/graemlins/grin.gif

 

[Mirelle]

Less \"anchoring technique\" and more seamanship would have been better

This very silly saga occurred because the "skipper" was preoccupied with "anchoring technique" - faffing about with backing anchors and weights - and forgot the basics. Heaven help the poor saps he/she was supposed to be "training".

Anchoring is easy: use a big anchor and a sensible length of heavy chain. If the forecast is for poor weather, set an anchor watch.

This is not rocket science; the Romans and the Vikings managed it.

And making a Pan broadcast on going aground...words fail me.

 

[Guest]

Re: Less \"anchoring technique\" and more seamanship would have been better

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And making a Pan broadcast on going aground...words fail me.

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Wouldn't it rather depend on the situation they went aground in? Going aground in a sheltered area on soft mud is one thing. Going aground on something harder in a place which might become more exposed if the weather changes in some respect is another... It's hard to judge all the circs from the printed word, so up to the skipper to assess, isn't it?

 

[jenku]

Re: Tandem set technique

There IS one totally fail proof technique of tandem anchoring: one anchor and one frogman with a big hammer on the same rode. When the anchor drags the frogman hammers it back in. /forums/images/graemlins/wink.gif

 

[PeterStone]

Re: Less \"anchoring technique\" and more seamanship would have been better

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Heaven help the poor saps he/she was supposed to be "training"

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Well..he certainly demonstrated how not to do it and the consequences of such an action. Let's hope that they have learned a valuable lesson. It has certainly reinforced my own opinions on good anchoring technique.

 

[Mirelle]

Re: Less \"anchoring technique\" and more seamanship would have been better

Frankly, I don't think, from the written report, that they were ever in a situation that justified a "Pan" call. The boat was not damaged, and floated off as the tide rose.

Pathetic