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Old 01-26-2009, 06:21 PM   #15
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Originally Posted by redbopeep View Post
you can set two anchors on one rode and greatly increase your chances of staying put. .

This technique is known as "TANDEM" anchoring and it has never be proved to increase the holding.

On an imaginary level, it might seem like two anchors should hold better than one. This is however only true when both anchors can set perfectly. Whatever anchoring technique you use, there's never a guarantee that both anchors are going to set well. On the contrary, once the first anchor is set in the seafloor, it will hinder the other anchor from setting also.

When an anchor has dragged, a trench formed behind it and this quickly backfilled with loose un-compacted sand. These areas can be still visible after several tides and may explain why some popular anchorages are criss-crossed with patches of poor holding.

Then, if the most proximal anchor set, they are very good chances (?) that the distal anchor will fall down in this loose bottom, with, as a consequence, a poor holding! and this is enough to explain why two tandem set anchors doesn't have twice the holding of one single anchor..

Therefore attaching two anchors to one rode, known as tandem anchoring, should be avoided.

Now, Redbopeep, may I suggest you to look at the anchors you are using??

- CQR, has been invented about 80 years ago! Much progress has been made since that time…

- Fisherman, this anchor has been invented in antic time, more than 2000 years ago!

May I suggest also you to try one of the "next gen" anchors? Then you will never think of using a complicated and unsafe technique…
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Old 01-26-2009, 06:57 PM   #16
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Hi Stephen,

Once more I should fight against all these "perceived wisdom"

Chain is the best way to avoid chaffing of the chain on the sea bottom...

It is the anchor that holds the vessel, note the rode... or if it is the case with your boat, it's time to look at another more efficient anchor!

Quote:
It is only in the worst conditions that the anchor cable is taut
With standard scope and rightly sized chain, the chain will start to be taut with winds up to 25/30 knots (see catenary formula) then if it is the chain which hold the boat you will get into trouble!

Holding of a chain alone on a sandy bottom is about twice its weight... nothing compared to the holding of any 'New Gen" anchor

Quote:
I for one would not sleep soundly if I did not have chain all the way from the vessel to the anchor.
If using an all chain rode, you MUST have any kind of elasticity, such as an efficient snubber or to use a mix chain/ rope rode.

For more explanations see: "tuning an anchor rode": alain.fraysse.free.fr/sail/rode/rode.htm
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Old 01-26-2009, 07:21 PM   #17
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Hmm, perceived wisdom?

Quote:
If using an all chain rode, you MUST have any kind of elasticity, such as an efficient snubber or to use a mix chain/ rope rode.
Ever seen a ship with a snubber? The only function a snubber performs is to make the boat ride more easily. If there is sufficient chain of sufficient dimension out this is not necessary. It would protect your paintwork though.

But to be fair, I have not tested a "New Gen" anchor. Perhaps I should and then reassess my opinion

Aye // Stephen
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Old 01-26-2009, 07:40 PM   #18
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Originally Posted by Ancoralatina View Post
...
Gracious. We all have our own opinions don't we?

Stephen, I agree that all chain is preferred--and this is our rode situation on this boat and the last one. And--is a must for the rode between the two anchors if one employs the series (tandom?) system I described.

Regarding the anchor in series technique I described, it does work both in theory and in practice it is a good technique, properly used, to assure holding. I can only vouch for the use of a plough primary and plough or fisherman series anchor, though as that is all I know will work for certain from my own experience or experience of a close friend who is a merchant mariner. I would be sure there are many other more experienced seamen who can discuss the matter than I. I just know it works. It is thought that the tandem anchor (in the case I suggested a fisherman) does its job not by providing any great "extra" holding at all but rather providing an ability to catch in case the primary anchor (in the case I gave CQR (Plough type) as example) drags. One is not doubling their holding power but rather simply trying to keep the holding power one started with

The primary is set first (and one hopes the secondary isn't needed) I do suggest the fisherman in that though it is difficult for it to be used as a successful primary anchor, when things drag, frequently the bottom is not as one thinks it is--there are rocks, trash, whatnot causing problems for the primary anchor, and in these situations a fisherman CAN catch onto seagrass, rocks or other debris which are making it difficult for other anchors to stay fast.

There are numerous types of anchors one may choose to use. And, many more modern than I reference. However, my own experience with appropriately sized CQR (plough), danforth/fortress (fluke) , and fisherman is they all work in bottom conditions suited to each. As an aside, I do believe that most sailors are trying to hold fast with anchors far too small for their boats and with too little chain on a combo chain/rope rode.

Fair winds,

P.S. Yes, I like good "old" technology that works Just because something is "modern" doesn't make it better... than 80 year old or thousands of years old technology. Only the advertisers and marketing folks will have you believe that!
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Old 01-26-2009, 08:01 PM   #19
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Ancoralatina, you seem to have very strong opinions about anchoring. What kind and size of boat do you have or are you a merchant mariner (and if so, what type of ships)? What are your cruising grounds or planned cruising grounds? What type of difficult anchoring conditions have you personally experienced that bring out such strong opinions?

Many people are sucked into advertisements and marketing glitz by various marine products--including anchors--it is always most interesting to learn about the experiences of other mariners with their own ground tackle rather than just hearing about an advertiser's product sales pitch.

Fair winds.
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Old 01-26-2009, 10:17 PM   #20
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Originally Posted by redbopeep View Post
Ancoralatina, you seem to have very strong opinions about anchoring.
Yes I have strong opinions about anchor and anchoring, all based both on matematics and on a very large expérience :

- King and size of boats ? I’ve been sailing for more than 50 years from dinghy to blue water cruisers, doing competition at National level, racing and fulltime living aboard for nearly 20 years in half of the seas of the world.

Last years, I’ve been involved in designing and testing anchors in one of the worst place of the world, Tierra de Fuego, Patagonia, and Antarctica….

I perfectly know all the "perceived wisdom" I can read on this forum and I will be more than pleased to deeply discuss them..

You may note that I didn’t make any sales pitch, not talking about any product brand. Please discuss technique and do not try to avoid answering technical questions behind such an excuse

But now ? may I ask you the same questions ? What kind and size of boat do you have, What are your cruising grounds and what is your anchoring experience ??

Fair winds and peaceful anchorages
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Old 01-26-2009, 10:32 PM   #21
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Originally Posted by Nausikaa View Post
Ever seen a ship with a snubber?
Sorry, if I am wrong! I was thinking this was a forum about yachts, not about merchant ship!

If ship are not using snubbers, nearly all blue water cruisers who are anchoring with an all chain rode are using snubbers when the conditions deteriorate.

It is very easy, using the catenary formula, to determine when the last link of chain will no longer be lying on the sea bed, and using a normal scope (5:1) and the rightly sized chain, as I said before – this will happen with about 25 to 30 knots of wind.

Then the chain will not make any more damping by catenary, and this is why, you should use a snubber.

For more detailed mathematical formulas, see: Tuning an anchor rode:alain.fraysse.free.fr/sail/rode/rode.htm
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Old 01-26-2009, 10:42 PM   #22
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Originally Posted by redbopeep View Post
Yes, I like good "old" technology that works Just because something is "modern" doesn't make it better... than 80 year old or thousands of years old technology. Only the advertisers and marketing folks will have you believe that!
As I tell my kids often "don't slag something until you've tried it".

Is that a relevant statement here?? I suspect it maybe.

If I may ask ? What is your experience comparing old generation of anchors with new tech ??
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Old 01-27-2009, 02:04 AM   #23
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Lynger1, now see what you've done. *You've started an*anchor thread, that much maligned, usually dreaded chain of arguing on, and on, and on about what is the best anchor, whose tests are valid, etc., etc.

My turn again to offer opinions, though I'm using others' experience as much as our own.

We have an old "advanced cruiser" friend whose home-built steel boat was his home in the Caribbean for many years. *He was a solo sailor, and would sail 50+ miles from St. Martin to Nevis just to buy 50 pounds of inexpensive sugar (there's another story here, but not for this thread). *He did not head to Venezuela for hurricane season, and safely rode out many tropical storms and hurricanes at anchor in his boat, including Luis and Hugo, two very destructive storms in the Carib. *

He had two techniques that worked exceptionally well for him.

His was a typical hard-chined home-built steel sloop, and because it liked to sail at anchor, in high winds he anchored from the stern, which stopped the sailing on the anchor. *His second technique was the tandem anchoring technique, and he swore by it, never having dragged in all the storms he'd been through. *During HUGO he jumped off his boat and swam to where another solo sailor had grounded his boat after he had lost all five (5)! of his anchors. *He helped the fellow secure the boat to the mangroves so it wouldn't be refloated and pushed into other boats anchored in the lagoon, then swam back to his boat (high winds but little fetch where he was anchored) which calmly waited for his return.

Another sailor who, after many troubles anchoring in Patagonia and Antarctica, found the tandem anchoring technique to be effective, was Gerry Smith who wrote about his Antarctic adventures in his book "THE TOTORORE VOYAGE". *In my opinion, a great read. *The engine on his boat seemed to fail to start when he really needed it, so secure anchoring was something he really needed.

Snubber. *We made a mistake and anchored too close to a reef protecting a beach in Fiji. *An unexpected storm caught a lot of boats facing violent winds and praying that their anchor would hold as the wind shift during the storm turned us around and put us all on a lee shore. *Peter is sure that it was the two snubbers on our all-chain anchor rode that kept the chain from breaking, or our bow rollers from shattering under the violent stresses of the winds and waves. *One of the two snubbers broke and Peter had to ride the bucking bow while he rigged a new snubber. *We got through that storm safely, and we are sure that the snubbers are what saved the ground tackle from failing as the result of shock loads.

I don't doubt that different boats will have different successful techniques for safely anchoring, and I am interested in hearing about them. * Let's not, though, toss out that which is old and tried and true because it's old-fashioned. *Show me a proven better anchor, gear, technique and spare me the "get with it, move into the 21st Century!"

Fair winds and calm anchorages,

Jeanne
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Old 01-27-2009, 05:38 AM   #24
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Quote:
Sorry, if I am wrong! I was thinking this was a forum about yachts, not about merchant ship!

If ship are not using snubbers, nearly all blue water cruisers who are anchoring with an all chain rode are using snubbers when the conditions deteriorate.
You are right. This is a forum about cruising yachts. However, just because w are cruising orientated does not mean that we should be blind for good practices found elsewhere.

My whole point in the comparison with merchant ships us the they have been anchoring far longer than yachts and, being much bigger the forced are greater yet they use relatively small anchors and cable - just lots of it!

If a yacht used the equivalent length of cable then she would ride much easier, the weight of the cable itself providing the cushioning action. Agreed that the snubber offers the paintwork more protection and, if they offer a smoother time at anchor, I have nothing against them (and use them myself)assuming that an adequate length of cable is deployed. The risk with a snubber is that some, because they are getting an easier ride, may be tempted to have too little scope of cable out.

I too am of the opinion that what is old and proven should not be tossed out just because something new is on the market.

Aye // Stephen
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Old 01-27-2009, 10:44 AM   #25
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Thanks to the author of this topic - it has illustrated the amount of experience that has gone into securing the cruising yacht - built on the history of former sailing ships - merchants vessels - and the experience of local sailors and fishermen in far flung lands.

Having used small tyres as snubbers when the tackle catenary was at full stretch - they do something for peace of mind.

Here is a site that provides a little light on the subject of the catenary :- CLICK
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Old 01-27-2009, 04:48 PM   #26
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... this is indeed an interesting and informative thread! There is alot to read about anchoring techniques.

But I start wondering, why I never had the idea or felt the need of bringing out more than one anchor.

Reflecting on the hundreds of situations of laying at anchor (Baltis Sea, Portugal, Spain, Caribbean) I simply found it not practical to put out more than one anchor:

- carrying an oversized anchor with 50 Meters of 8mm chain on my 5ton boat creates alot of safety.

- what a hastle to bring out two anchors and what happens if the wind shifts?

- what about angry neighbours on an anchorage if some boats chose to use two anchors and others didn't... and then the wind shifts?

- in a deteriorating situation nothing is easier to get out just one hook and leave for a safer place.

- good seamanship is keeping an anchor watch all the time your boat is at anchor - i.e. not leaving the boat over a longer period of time,

and if, just under stable weather conditions and maybe telling the neighbouring yacht (you can trust) to keep an eye on your boat.

- always using a marina when we planned to leave the boat over night or longer.

- even bow or stern to a tree or rock (done more often in the Baltic, as Stephen already described) can be risky: just imagine your anchor just slipping a little... your bow hits the rock. And this can happen faster then one can imagine. It happened to us in Norway, tied up to a rock, anchor out astern and a gentle breeze started in the afternoon from abeam... We were just gone for half an hour, the anchor slipped and we were so happy that we had some nice Norwegian neighbours who realized the situation.... Since then we prefer anchoring free, giving the anchor a chance to dig back in again in case it should come free. Enough room leewards is of corse necessary to decide in time if one should better leave. And this even in Sweden and Norway, where anchoring irritatingly close bow to the rocks is nearly standard.

SY Aquaria

Uwe

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Old 01-27-2009, 05:15 PM   #27
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Well said Uwe. I could not agree more.

Good seamanship is, I believe, represented by the acronym MCS - Mostly Common Sense.

Uwe's post is the zenith of common sense.

But that is just my opinion of course although I think most will agree.

Aye // Stephen
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Old 01-27-2009, 08:21 PM   #28
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Lynger1, now see what you've done. You've started an anchor thread, that much maligned, usually dreaded chain of arguing on, and on, and on about what is the best anchor, whose tests are valid, etc., etc.

Jeanne
Thanks! Jeanne for giving us your experiences and for pointing us back to our original goal here--which is to support Lynger1 in his desire to safely anchor

We all have what we have in terms of ground tackle and learning how to use it to best advantage is the goal! Seldom do cruisers have the luxury of going out and buying new anchors--though extending the amount of chain one owns is always a goal.

Good luck to Lynger1 in his quest for the best anchoring given his situation.
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