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Absolute Best Ankr?

Neeves

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20 Nov 2011
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why on earth should i do that! I've got a perfectly good cqr with a swivel and chain. Works every time for me. I've also got 100 m of octoplait after my 50m of chain which I can deploy in extreme conditions or depth. I don't see the point in setting an anchor in a way that requires a diver with an underwater walkie talkie to set it right! I just want something that works first time, everytime just by chucking it over the side paying out 5 times the depth and engaging a bit of reverse to dig it in.
Jimi,

You were the one who said a good anchor was one with a shed load of chain - you are wrong. No-one said you had to try it as common practice.

Jonathan
 

Neeves

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How can a Rocna clog but a Spade doesn’t ?
The seabed is compressed and restrained between the roll bar and fluke plate. Spade has no such restriction.

If you watch people retrieving a Rocna (and some will admit to same on this forum) you will note that in certain seabeds the anchor lifts mud, or seabed, as it is retrieved. This is then removed with a deck wash or by dangling the anchor in the sea as the yacht moves off. You will not see this, so much, with a Spade. Now imagine if the anchor is tripped with this same clot of mud in the anchor - it will not re-set until the clog is removed (or almost removed). The more difficult it is to clean the greater the risks that the anchor will not reset - so the longer it takes the bigger the risk.

In sand this is really not an issue - the sand usually washes off during retrieval.

Jonathan
 

Bouba

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The seabed is compressed and restrained between the roll bar and fluke plate. Spade has no such restriction.

If you watch people retrieving a Rocna (and some will admit to same on this forum) you will note that in certain seabeds the anchor lifts mud, or seabed, as it is retrieved. This is then removed with a deck wash or by dangling the anchor in the sea as the yacht moves off. You will not see this, so much, with a Spade. Now imagine if the anchor is tripped with this same clot of mud in the anchor - it will not re-set until the clog is removed (or almost removed). The more difficult it is to clean the greater the risks that the anchor will not reset - so the longer it takes the bigger the risk.

In sand this is really not an issue - the sand usually washes off during retrieval.

Jonathan
I think about this a lot because when I lift the Rocna I do get clots of sand/mud. But I lift the anchor UP an not drag it out. So I don’t see that as relevant, it’s a shovel, if you pull it up at the right angle it should be full. That’s how it holds.
 

Neeves

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If it is sand it falls out because it is not cohesive. Mud is cohesive and compresses and sticks to the fluke plate restrained by the roll bar.

When any, good, anchor sets the fluke plate is at an angle of 30 degrees to the seabed. When setting the anchor is dragged forward, through the seabed - and usually sets in a shank length. The seabed through which the Rocna is pulled is driven over the fluke plate - and to escape has to pass under the roll bar - because that is how a concave anchor directs the seabed - like a channel. As the anchor dives and there is more seabed being shovelled under the roll bar it becomes so much it hits the roll bar and is then compressed. If the anchor does not move any more then:

When you lift the anchor that clot of mud stays intact as you lever the anchor out with the shank - yes that is offering the hold but if you say, tripped the anchor due to a tide or wind change - that clot is still there. The clot now offers no hold, because it is no longer 'part' of the seabed but has completely altered the geometry of the fluke.

A convex anchor works differently - it shovels the seabed aside, not over the fluke plate - the fluke in effect is self cleaning. But the fluke plate is still compressing the seabed immediately in front of (and above the diving fluke) and it is this compressed seabed that is providing the hold. If the Convex anchor breaks out it does not have that compressed seabed 'in' the fluke and it largely falls off - leaving you with a clean fluke - as the anchor was designed.

There are other differences - the perforated fluke appears to allow the fluke to better self clean, this is why the Excel is full of holes, the Viking has all those holes and why Knox have left the slot in their fluke. 3 independent designs have the same reasoning. What Knox found was that if they filled the slot the fluke clogged (like a Rocna) but self cleaned if left open - that's why it has not been closed. I'm telling no secrets - this has been posted of Knox previously.

In all cases the seabed above the fluke is cohesive - its all joined packed together - its that cohesiveness that actually offers the hold (not the clot of seabed in the fluke). So the seabed ahead of and above the seabed, which has been compressed a bit is still part of the rest of the seabed and it is the integrity of that mass of seabed that provides the hold. For the anchor to drag that cohesiveness has to be broken. When you break the anchor out there is not much volume immediately above the fluke. But ahead of the fluke - assuming the tension is well forward of the anchor - there is a lot of seabed resisting movement.

If you are on the beach (or building site) - it is difficult to drag a shovel with its fluke plate vertical, or even at 30 degrees, through the sand (or through wet concrete), but dead easy to dig a shovel full of sand (or cement) out.

Jonathan
 
Last edited:

Bluetack42

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7 Apr 2020
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39
The seabed is compressed and restrained between the roll bar and fluke plate. Spade has no such restriction.

If you watch people retrieving a Rocna (and some will admit to same on this forum) you will note that in certain seabeds the anchor lifts mud, or seabed, as it is retrieved. This is then removed with a deck wash or by dangling the anchor in the sea as the yacht moves off. You will not see this, so much, with a Spade. Now imagine if the anchor is tripped with this same clot of mud in the anchor - it will not re-set until the clog is removed (or almost removed). The more difficult it is to clean the greater the risks that the anchor will not reset - so the longer it takes the bigger the risk.

In sand this is really not an issue - the sand usually washes off during retrieval.

Jonathan
I beg to differ, I have used a 20kg steel Spade anchor as my only anchor for the last 10 years, anchoring variously in sand & mud. I am a huge fan of the spade.....BUT, as the years have gone by and the yellow top paint has become deeply scared & roughed up, I get larger & larger balls of mud remaining attached when I retrieve, its fine with sand, mud is the problem. I had to lean dangerously over the forstay & use a garden spade to dig it off, dipping back in the water was no help, typically I got at least a 5li bucket full or more. The problem is if I attempt to re-anchor without cleaning then the ball of mud sits on top & slides along, the lead weighted tip is unable to penetrate.

My recent attempt to deal with this has been to repaint the whole thing, grey with the top of the flukes yellow, I used a tough paint with a gloss finish like the original, so far this has been a dramatic improvement, once again the mud slides off when the flukes are near vertical, I am hoping for many more years of sleeping soundly at anchor.
 

jimi

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Jimi,

You were the one who said a good anchor was one with a shed load of chain - you are wrong. No-one said you had to try it as common practice.

Jonathan
I don’t consider myself wrong, a good anchor is one that holds with minimum problem. The fact you can set an anchor very carefully in very specific circumstances with nylon at 30 degrees doesn’t mean it is a good anchor it merely means you can set it in these circumstances. A better anchor may not set in that way but may if fact set better with chain to get the correct set angle.
 

zoidberg

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12 Nov 2016
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When your modern anchor sets ...... it drags down chain and the chain is also buried. However the chain has surface area and resists penetration and develops a reverse catenary.
If you want to maximise the performance of your anchor - reduce the chain size, reduce the shackle size and throw away the swivel..... you need to have a chain and shackle of the correct strength .....
I'm regularly dismayed by those stick-in-the-muds who refuse to consider 'a better way', and encouraged by those few who 'explore alternatives' - like Jon Reeves.
We didn't always use chain-cable for anchoring - other flexible-fibre constructions were used in days of yore, with all their advantages and limitations. With recent improvements in materials science, we could again.

Famous - and successful - RORC racing skipper Adlard Coles was one of those who 'thought outside the box'. He wasn't keen on the considerable weight of the chain-cable conventionally carried and so he carried a much lighter drum of thin piano wire - which he used successfully on several occasions. I took that idea and deployed several hundred feet of 6mm sheathed aramid 'pull cord' on a Fastnet race, twice, when deep-water kedging was indicated. Others didn't have the means, and it gained us more than half-an-hour and more than a dozen places....
....And we won our Class and Series.

Could one reasonably use a 20-odd feet length of 4mm flexible steel wire rope ( for abrasion ) and 200-odd feet of 5mm sheathed dyneema? That's about 4lbs weight - or two ( English ) bags of sugar. What small fraction of your existing chain-cable would that weigh...?


Oh, and in case you're asking, the World Sailing Offshore Special Regulations seem to require simply 'a suitable combination of chain and rope'.
 
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Neeves

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Friction plays a role in how an anchor, and its fluke works. A rough fluke has more friction and will retain more seabed (and will not dive so deeply nor develop the hold it did when new). An old rusty anchor not much used will not work as well as one with a shiny new coating of galvanising. If you use your anchor regularly - it will self polish. Shiny stainless is ideal, except it does not stay shiny very long and costs a fortune. Friction is one reason a new Fortress will outperform a galvanised Danforth, though this is a bit of a phurphy as the Fortress also has a thinner fluke plate than the same sized Danforth.

The nuances of anchors and anchoring is not quite as simple as we all hope.

Just keep thinking - there is no perfect anchor.

Jonathan.
 

vyv_cox

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16 May 2001
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23,131
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France, sailing Aegean Sea.
I don’t consider myself wrong, a good anchor is one that holds with minimum problem. The fact you can set an anchor very carefully in very specific circumstances with nylon at 30 degrees doesn’t mean it is a good anchor it merely means you can set it in these circumstances. A better anchor may not set in that way but may if fact set better with chain to get the correct set angle.
I have been setting my Fortress anchor on a nylon anchorplait rode for more than 20 years. It is our kedge, so the majority of sets have been in a fork moor, always in a lot of wind, with many as a stern anchor and some as the primary anchor in emergency (windlass failure) and sometimes by choice as primary anchor.

On one occasion due to confusion over rode markings we anchored in a full gale for three days at a scope of 3:1. The Fortress is never set 'very carefully', in fact most often it is simply dropped from the dinghy while unable to see the quality of the seabed.

It has never dragged. When I have swum on it it has invariably been well set even in very unfavourable seabeds.
 

jimi

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I have been setting my Fortress anchor on a nylon anchorplait rode for more than 20 years. It is our kedge, so the majority of sets have been in a fork moor, always in a lot of wind, with many as a stern anchor and some as the primary anchor in emergency (windlass failure) and sometimes by choice as primary anchor.

On one occasion due to confusion over rode markings we anchored in a full gale for three days at a scope of 3:1. The Fortress is never set 'very carefully', in fact most often it is simply dropped from the dinghy while unable to see the quality of the seabed.

It has never dragged. When I have swum on it it has invariably been well set even in very unfavourable seabeds.
Viv , I was responding to post #17. I've also used a Fortress( and a Brittany) with nylon only rode, only issue I had was retrieving them.
 

Neeves

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It is well known that increasing scope ratio from say 2:1 to 7:1 will result in an increase in hold. Beyond about 7:1 any increases are marginal and might be more influenced by changes in seabed than changes in scope. This increase in performance is common to most designs - but older anchors tend not to work, at all, at the steeper rode angles, so a CQR will struggle to set at 2;1, but a Fortress might be possible.

Arguably anchors that can be more reliable at high rode angles, 2:1 and 3;1 are much better than an anchor that needs a shed load of chain - as in an emergency you may not have room to deploy a shed load of chain - and a scope of 3:1 of an anchor you just lob over the side that sets is just what you want in an emergency.

Most modern anchors Rocna, Spade Fortress etc will engage if you simply chuck them in the sea and apply tension, even if that tension is applied with a bit of nylon or piano wire. Most old designs will simply drag on the seabed.

To me a good anchor, or even ancre, is one that sets without much care, that sets with any old (but reliable) bit of rope and does this quickly and consistently in most seabeds.

There is no doubt deploying a shed load of chain can be very effective - but carrying a shed load of chain is unnecessary - if you believe in snubbers. and vessel performance (and don't really fancy spend the cash on the shed load of chain). Carrying a shed load of chain has additional problems - if your anchor only works with all that chain and you need to deploy from a dinghy.

If your anchor needs a shed load of chain in order to be reliable - I would not touch it (given the good designs we have available) and certainly would never recommend it.

Each to their own - fortunately it is still a free world.

Jonathan
 

claymore

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The Noble Laird Claymore registers his disappointment that his Faithful Auld Retainer Bruce, was not mentioned.
 

jimi

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It is well known that increasing scope ratio from say 2:1 to 7:1 will result in an increase in hold. Beyond about 7:1 any increases are marginal and might be more influenced by changes in seabed than changes in scope. This increase in performance is common to most designs - but older anchors tend not to work, at all, at the steeper rode angles, so a CQR will struggle to set at 2;1, but a Fortress might be possible.

Arguably anchors that can be more reliable at high rode angles, 2:1 and 3;1 are much better than an anchor that needs a shed load of chain - as in an emergency you may not have room to deploy a shed load of chain - and a scope of 3:1 of an anchor you just lob over the side that sets is just what you want in an emergency.

Most modern anchors Rocna, Spade Fortress etc will engage if you simply chuck them in the sea and apply tension, even if that tension is applied with a bit of nylon or piano wire. Most old designs will simply drag on the seabed.

To me a good anchor, or even ancre, is one that sets without much care, that sets with any old (but reliable) bit of rope and does this quickly and consistently in most seabeds.

There is no doubt deploying a shed load of chain can be very effective - but carrying a shed load of chain is unnecessary - if you believe in snubbers. and vessel performance (and don't really fancy spend the cash on the shed load of chain). Carrying a shed load of chain has additional problems - if your anchor only works with all that chain and you need to deploy from a dinghy.

If your anchor needs a shed load of chain in order to be reliable - I would not touch it (given the good designs we have available) and certainly would never recommend it.

Each to their own - fortunately it is still a free world.

Jonathan
When I've deployed a Fortress in a blow my issue has been retrieving it as it digs in really well. As my windlass is manual I'd rather have chain to haul in (even a shed load) rather than having a huge effort getting the thingie out from halfway to Australia. To me the "good" attributes of a anchor encompass the entire experience, from 1)setting it, 2)confidence in it whilst deployed through to 3)ease of retrieval. Obviously type of boat, size of boat, location, hardware, situation and crew matter, kedging in the Fastnet is a vastly different kettle of fish to lunchtime anchoring in Lulworth, anchoring off Novaya Zemlya or any mix in between. This obviously means there is no one best answer that suits everyone ergo there is not such as a best anchor. for everyone. In the language of quality assurance, the best one is the one that does the job for you with minimum effort and cost.
 

Bouba

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When I've deployed a Fortress in a blow my issue has been retrieving it as it digs in really well. As my windlass is manual I'd rather have chain to haul in (even a shed load) rather than having a huge effort getting the thingie out from halfway to Australia. To me the "good" attributes of a anchor encompass the entire experience, from 1)setting it, 2)confidence in it whilst deployed through to 3)ease of retrieval. Obviously type of boat, size of boat, location, hardware, situation and crew matter, kedging in the Fastnet is a vastly different kettle of fish to lunchtime anchoring in Lulworth, anchoring off Novaya Zemlya or any mix in between. This obviously means there is no one best answer that suits everyone ergo there is not such as a best anchor. for everyone. In the language of quality assurance, the best one is the one that does the job for you with minimum effort and cost.
Absolutely agree. The only problem is that most people only have room for one anchor. So perhaps the question should be, ‘what is the best compromise for an anchor?’
 

zoidberg

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Absolutely agree. The only problem is that most people only have room for one anchor. So perhaps the question should be, ‘what is the best compromise for an anchor?’
Nah! It's their sporrans that only have room for one ankr!

Perhaps someone should invent 'nesting ankrs'.... like those Russian Dolls..... :giggle:
 

Bouba

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Nah! It's their sporrans that only have room for one ankr!

Perhaps someone should invent 'nesting ankrs'.... like those Russian Dolls..... :giggle:
We go to a lot of effort to find that perfect spot, if I then said to the wife, now dear, I need you to take the helm and hover over this exact spot for half an hour, and make sure no one anchors behind us. While I choose an anchor, get it out of storage, remove the existing anchor and then attach it. Her response is likely to be 😡🤬🤬🤯🥶
 

claymore

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I thought this thread was about anchors - you seem to be drifting it towards the unreasonableness of wives when crewing.
I usually float the old 'Love, Honour and OBEY ' routine. Naturally it cuts no mustard.....
 

zoidberg

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We go to a lot of effort to find that perfect spot, if I then said to the wife, now dear, I need you to take the helm and hover over this exact spot for half an hour, and make sure no one anchors behind us. While I choose an anchor, get it out of storage, remove the existing anchor and then attach it. Her response is likely to be 😡🤬🤬🤯🥶
Doesn't sound to me like a well-structured and capable crew complement. Suggest you take your mistress boating, instead. Or someone else's mistress...
Perhaps you're not the 'master and commander' type.
 
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