An Anchor Thread! Grab your beers and popcorn.

[boomerangben]

The loads have all been calculated and measured. The data is available to view from many sources, both attached to YBW threads and externally.
You need to read more anchor threads in the archive.

True, I haven’t done extensive research on old threads but have followed many. I found the ABYC table before Neeves kindly attached and also the data by another who found wildly different figures. Indeed whilst Neeves has sort of validated the ABYC table with 625kg from his own experiment vs 1400lbs for the ABYC, Neeves points out that the 625kg was experienced as a peak load with an all chain/dynema rode with negligible elasticity. But the moment you put a mixed rode or snubber into the rode, what are the loads? Since peak loads are by definition dynamic, the displacement, mass distribution, underwater profile, entrained mass of water become significant together with the energy absorbing characteristics of the rode. Length provides a pretty poor correlation to the above in my opinion.
I am a convert to modern thinking on anchor rodes, have an aluminium anchor with a short length of chain and lots of nylon. So all the loads above, together conventional thinking on anchor mass are left wanting.
I would love to know how accelerations at the bow roller differ between an all chain rode and a mixed rode/snubber arrangement. It is accelerations that make us fall out of bunks, rip cleats out, causes connector failure and dislodges anchors and determines the tension in a dynamic anchoring system. A better understanding of this will lead to cheaper set ups and more comfortable nights sleep (unless you are around rocks and coral of course)

As for the OP, I wouldn’t change the rode, but choose the right size anchor of his choice from modern SHHP or even HHP anchors. Modern anchors rely on the area of the shear plane in the seabed soil around the anchor, which depends on fluke perimeter and depth of burial so oversizing might reduce burial depth and therefor overall holding power. But above all as Neeves says, choose the right anchor for the seabed or choose your seabed based on your anchor.

 

[RunAgroundHard]

True, I haven’t done extensive research on old threads but have followed many. I found the ABYC table before Neeves kindly attached and also the data by another who found wildly different figures. Indeed whilst Neeves has sort of validated the ABYC table with 625kg from his own experiment vs 1400lbs for the ABYC, Neeves points out that the 625kg was experienced as a peak load with an all chain/dynema rode with negligible elasticity. But the moment you put a mixed rode or snubber into the rode, what are the loads? Since peak loads are by definition dynamic, the displacement, mass distribution, underwater profile, entrained mass of water become significant together with the energy absorbing characteristics of the rode. Length provides a pretty poor correlation to the above in my opinion.
I am a convert to modern thinking on anchor rodes, have an aluminium anchor with a short length of chain and lots of nylon. So all the loads above, together conventional thinking on anchor mass are left wanting.
I would love to know how accelerations at the bow roller differ between an all chain rode and a mixed rode/snubber arrangement. It is accelerations that make us fall out of bunks, rip cleats out, causes connector failure and dislodges anchors and determines the tension in a dynamic anchoring system. A better understanding of this will lead to cheaper set ups and more comfortable nights sleep (unless you are around rocks and coral of course)

As for the OP, I wouldn’t change the rode, but choose the right size anchor of his choice from modern SHHP or even HHP anchors. Modern anchors rely on the area of the shear plane in the seabed soil around the anchor, which depends on fluke perimeter and depth of burial so oversizing might reduce burial depth and therefor overall holding power. But above all as Neeves says, choose the right anchor for the seabed or choose your seabed based on your anchor.

Your are over thinking it, a sort of analysis paralysis. The fact is that absolute values are irrelevant in this case. The design of your rode and anchor can use rules of thumb, such as those found in Ian Nicholson's books (Scottish yacht designer and surveyor of note) or equipment supplier data sheets. Understanding of stuff always develops and keeping up with latest facts and techniques can be useful, bt it does not mean that it has to be applied, especially if what we use is good enough.

As said by others in this thread, many of us buy the boat with the stuff already fitted. By understanding its abilities, performance capabilities and thus it weaknesses, most of the anchor and rode assemblies will work satisfactorily.

An Example
The impact of a yacht shearing and snubbing loads on an anchor has been shown that to can reduce the ability of the anchor to hold. Using a snubber reduces that risk further because it lessens the peaks loads as a result of shearing at some velocity. My experience, from owning a yacht that shears significantly, is that my anchor, in mud, does not break out. So I am not interested in rigging up a snubber, beyond the mini chain hook snubber to take the load from my windlass. That doesn't mean that if I was in a situation where holding was questionable and winds were strong, that I would not use a snubber. It would stupid not to use it if the conditions dictated. However, what I have done in the past, when my boat was being slammed over at 45 degrees at anchor, was to use the chain hook to switch from bow to stern anchoring. In an instant my boat stopped veering and healing.

 

[Supertramp]

Your are over thinking it, a sort of analysis paralysis. The fact is that absolute values are irrelevant in this case. The design of your rode and anchor can use rules of thumb, such as those found in Ian Nicholson's books (Scottish yacht designer and surveyor of note) or equipment supplier data sheets. Understanding of stuff always develops and keeping up with latest facts and techniques can be useful, bt it does not mean that it has to be applied, especially if what we use is good enough.

As said by others in this thread, many of us buy the boat with the stuff already fitted. By understanding its abilities, performance capabilities and thus it weaknesses, most of the anchor and rode assemblies will work satisfactorily.

An Example
The impact of a yacht shearing and snubbing loads on an anchor has been shown that to can reduce the ability of the anchor to hold. Using a snubber reduces that risk further because it lessens the peaks loads as a result of shearing at some velocity. My experience, from owning a yacht that shears significantly, is that my anchor, in mud, does not break out. So I am not interested in rigging up a snubber, beyond the mini chain hook snubber to take the load from my windlass. That doesn't mean that if I was in a situation where holding was questionable and winds were strong, that I would not use a snubber. It would stupid not to use it if the conditions dictated. However, what I have done in the past, when my boat was being slammed over at 45 degrees at anchor, was to use the chain hook to switch from bow to stern anchoring. In an instant my boat stopped veering and healing.

Explain a bit more about using the chain hook to switch from bow to stern anchoring. Do you mean you ended up mooring stern to the wind? Presumably in a spot sheltered from waves?

I think practical experience is invaluable in learning anchoring, and those doing it day in day out will be acquiring the techniques and knowledge of when to use them.

I'm still at the "each time is an experiment" stage especially where unexpected wind or waves arrive.

 

[RunAgroundHard]

Explain a bit more about using the chain hook to switch from bow to stern anchoring. Do you mean you ended up mooring stern to the wind? Presumably in a spot sheltered from waves?

I think practical experience is invaluable in learning anchoring, and those doing it day in day out will be acquiring the techniques and knowledge of when to use them.

I'm still at the "each time is an experiment" stage especially where unexpected wind or waves arrive.

I have done this manoeuvre with the chain hook and with a snatch block. Attache a long line to the chain hook, attach the chain hook to the anchor rode outside everything, at the bow. Take the chain hook line to the stern, through a block cleat, snatch block and to the primary winch. Let the anchor rode out and the boat swings round hanging by the chain hook. Winch in chain hook line, take up any slack in the chain.

The stern does get slapped with waves. However, if they were so big as to be an issue, I wouldn't stay anchored there.

 

[geem]

I have done this manoeuvre with the chain hook and with a snatch block. Attache a long line to the chain hook, attach the chain hook to the anchor rode outside everything, at the bow. Take the chain hook line to the stern, through a block cleat, snatch block and to the primary winch. Let the anchor rode out and the boat swings round hanging by the chain hook. Winch in chain hook line, take up any slack in the chain.

The stern does get slapped with waves. However, if they were so big as to be an issue, I wouldn't stay anchored there.

Sounds like a technique for flat water. In which case I am not really sure of it's value? How does it help?. If you are veering why not add a riding sail and a long snubber?

 

[RunAgroundHard]

Sounds like a technique for flat water. In which case I am not really sure of it's value? How does it help?. If you are veering why not add a riding sail and a long snubber?

A snubber would not stop veering in my boat. I don’t own a riding sail nor would I want extra windage in the conditions I have stated. However, I have read (Piote”s ?) posts on his riding sail and clearly it worked well in very strong winds, so it is a possible solution. You are implying I am lying as I have stated that it works, for my boat and it helps by eliminating veering. Waves heights were about 2’ / 4’ in this conditions, very strong winds, weather shore shelter, at worst.

Why do you think what I am saying about my experience is wrong? I am curious why you dismiss it, or want to invalidate it.

 

[geem]

A snubber would not stop veering in my boat. I don’t own a riding sail nor would I want extra windage in the conditions I have stated. However, I have read (Piote”s ?) posts on his riding sail and clearly it worked well in very strong winds, so it is a possible solution. You are implying I am lying as I have stated that it works, for my boat and it helps by eliminating veering. Waves heights were about 2’ / 4’ in this conditions, very strong winds, weather shore shelter, at worst.

Why do you think what I am saying about my experience is wrong? I am curious why you dismiss it, or want to invalidate it.

Wow! I am not saying you are wrong. I just don't understand how you can be slammed over at 45 degrees and rigging the anchor to the stern solves this. What boat do you have? What wind speed slams you over at 45 degrees? What size waves? I have never seen anybody anchor by the stern in conditions that would set any boat over at 45 degrees

 

[RunAgroundHard]

Wow! I am not saying you are wrong. I just don't understand how you can be slammed over at 45 degrees and rigging the anchor to the stern solves this. What boat do you have? What wind speed slams you over at 45 degrees? What size waves? I have never seen anybody anchor by the stern in conditions that would set any boat over at 45 degrees

Rival 41C, about 60kt gusts. I told you the wave heights. How can you contribute if you don’t under stand how a boat can be laid over at anchor? I’ll grant that the angle was not measured but the worst knock over caused quite a heal and stuff falling about. As my boat skews, the bow blows down wind as there is greater windage forward of the CLR. Before the stern catches up with the veered boat, a big gust slams into the boat and she heals over. Boat recovers, repeats as the day goes on.

Look, if you want to doubt me, do it, it doesn't change the facts of my experience. I sail all year round, so if I have an opportunity, I’ll video the method to demonstrate results, but anyone can try it in winds that cause their boats to veer.

I first discovered this leaving a mooring under sail. We hung the boat by the stern, rolled out a bit of jib, sailed away in control. I noticed that the veering stopped.

 

[boomerangben]

Your are over thinking it, a sort of analysis paralysis. The fact is that absolute values are irrelevant in this case. The design of your rode and anchor can use rules of thumb, such as those found in Ian Nicholson's books (Scottish yacht designer and surveyor of note) or equipment supplier data sheets. Understanding of stuff always develops and keeping up with latest facts and techniques can be useful, bt it does not mean that it has to be applied, especially if what we use is good enough.

As said by others in this thread, many of us buy the boat with the stuff already fitted. By understanding its abilities, performance capabilities and thus it weaknesses, most of the anchor and rode assemblies will work satisfactorily.

An Example
The impact of a yacht shearing and snubbing loads on an anchor has been shown that to can reduce the ability of the anchor to hold. Using a snubber reduces that risk further because it lessens the peaks loads as a result of shearing at some velocity. My experience, from owning a yacht that shears significantly, is that my anchor, in mud, does not break out. So I am not interested in rigging up a snubber, beyond the mini chain hook snubber to take the load from my windlass. That doesn't mean that if I was in a situation where holding was questionable and winds were strong, that I would not use a snubber. It would stupid not to use it if the conditions dictated. However, what I have done in the past, when my boat was being slammed over at 45 degrees at anchor, was to use the chain hook to switch from bow to stern anchoring. In an instant my boat stopped veering and healing.

I am absolutely over thinking it, the engineer in me wants to know more, understand more and maybe have a more elegant solution. And I agree just because there’s new stuff or ideas, doesn’t mean to say you can’t continue with old methods. I like your lateral thinking solution to your predicament with violent shearing

 

[geem]

Rival 41C, about 60kt gusts. I told you the wave heights. How can you contribute if you don’t under stand how a boat can be laid over at anchor? I’ll grant that the angle was not measured but the worst knock over caused quite a heal and stuff falling about. As my boat skews, the bow blows down wind as there is greater windage forward of the CLR. Before the stern catches up with the veered boat, a big gust slams into the boat and she heals over. Boat recovers, repeats as the day goes on.

Look, if you want to doubt me, do it, it doesn't change the facts of my experience. I sail all year round, so if I have an opportunity, I’ll video the method to demonstrate results, but anyone can try it in winds that cause their boats to veer.

I first discovered this leaving a mooring under sail. We hung the boat by the stern, rolled out a bit of jib, sailed away in control. I noticed that the veering stopped.

I fully understand how a boat behaves at anchor. My boat spend most of its time at anchor. I have plenty of experience of anchoring in testing conditions. I was trying to understand your anchoring practises but seeing as you have your hackles up I think I will just park it there. It's not worth the effort

 

[RunAgroundHard]

I fully understand how a boat behaves at anchor. My boat spend most of its time at anchor. I have plenty of experience of anchoring in testing conditions. I was trying to understand your anchoring practises but seeing as you have your hackles up I think I will just park it there. It's not worth the effort

You claimed my technique has no value. I was clear what I did and what was the outcome. You chose to doubt my experience. I think my explanations should give you all the information you need to understand this anchoring practise. I make no claim how effective it would be on other boats with a different hull shape to mine. It’s simple really.

 

[NormanS]

I do things to help the situation in strong winds. OK, I have a ketch, so probably I'm never going to yaw around as much as a sloop. In order to reduce yawing to a minimum, I rig a riding sail. Again, it's easy for me, as the riding sail has slides, and is hoisted up the mizzen mast, and sheeted out to each quarter. I could just use the reefed mizzen, but even if it was very flat cut, it would have no benefit until the boat was well away from being head to wind. With my twin sail, with the clews sheeted tight out to the quarters, the wind is in it all the time, keeping the boat very nearly head to wind all the time.
I read here about people experiencing jerking loads on their anchor rode, when the boat yaws from side to side. By doing something to help her, my boat simply doesn't.

 

[Arcady]

Thanks Jonathan for the comprehensive reply. The account of anchoring through the Med storm with 70 kts of wind was interesting - particularly as they were lying to a humble CQR. (Cue much discussion from the pundits).

 

[geem]

I do things to help the situation in strong winds. OK, I have a ketch, so probably I'm never going to yaw around as much as a sloop. In order to reduce yawing to a minimum, I rig a riding sail. Again, it's easy for me, as the riding sail has slides, and is hoisted up the mizzen mast, and sheeted out to each quarter. I could just use the reefed mizzen, but even if it was very flat cut, it would have no benefit until the boat was well away from being head to wind. With my twin sail, with the clews sheeted tight out to the quarters, the wind is in it all the time, keeping the boat very nearly head to wind all the time.
I read here about people experiencing jerking loads on their anchor rode, when the boat yaws from side to side. By doing something to help her, my boat simply doesn't.

We don't veer in the normal sense. We also have a ketch. I have been in some anchorages where getting hit from the side by gusts over 40kts heels us over. (This is due to a steep hill that had winds coming from one side then the other.) We effectively veer until load comes on the snubber and pulls the bow around into the new wind direction. The snubber helps to reduce any snatch in these conditions.
In normal gusty conditions (with no hill Infront) we are one of the few boats that doesn't veer, even without a riding sail. Boat weight, a deep draft of 7'2"and a long fin (6000kg if lead) ensure we are not one of the variety of boats that sail around the anchor

 

[Neeves]

There are a whole long list of benefits of ketches, their performance at anchor being but one.

Sadly the pool of yachts at affordable prices either new or second hand does not include many ketches and the bulk of owners sail AWBs.

However even if you are selective and wait till that ketch comes on the market then yawing can be a function of the geography of the anchorage in which you are sheltering - and then, as Geem describes. you can be subject to a yawing wind - about which you can do little - except move. It is not simply a hill that causes yawing but gaps in trees, valleys that look charming and insignificant - until the winds are 40 knots out in the open - and then you enjoy those bullets of super accelerated winds.

Yawing at anchor does not simply engender snatch loads but also reduces the hold of your anchor

Hopefully this article is not behind a paywall

Yawing and Anchor Holding - Practical Sailor

But anchoring in a 'V or fork will reduce the impact of a yawing wind - not so handy as raising a riding sail - but it offers more security than a single anchor - and is one reason to carry 2 anchors, both of which can be a primary.

Even in open areas the wind can yaw:

Airports are commonly built in open flat areas, with no hills and trees at a safe distance. Just watch aircraft coming in to land in strong wind and they yaw all over the place and look decidedly uncomfortable (and more so if you are a passenger). Wind becomes unstable simply dues to minor changes in the land surface - its the same in an anchorage. Sadly the more sheltered and cosy the anchorage, without wind, and the same location can be plagued with bullets of wind.

 

[Neeves]

Thanks Jonathan for the comprehensive reply. The account of anchoring through the Med storm with 70 kts of wind was interesting - particularly as they were lying to a humble CQR. (Cue much discussion from the pundits).

The much maligned CQR was obviously success as it has been used for decades and if every other time it was used yachts dragged - we would know. It has been some years since you could buy a genuine CQR, made to the original design, and though old ones are cheap as chips they too are not of the original design - as the hinge wears with use. This latter will also contribute to the poor reputation of the CQR, nothing wrong with the original - but current models all have worn hinges. You can have them sleeved - but its simply easier to complain and buy a new design (of which there are now many)

Sadly the CQR needed patience to set and the newer designs are so much more forgiving. The new designs also allow development of the same hold - for less weight - and in the grand scheme of things investing in a new anchor is hardly expensive. I recall Kukri found a genuine CQR largely unused - but I suspect he was lucky.

The idea of a new design that you can deploy, gently, or violently, set - without a second thought has immense merit.

Jonathan

 

[KeelsonGraham]

You claimed my technique has no value. I was clear what I did and what was the outcome. You chose to doubt my experience. I think my explanations should give you all the information you need to understand this anchoring practise. I make no claim how effective it would be on other boats with a different hull shape to mine. It’s simple really.

Years ago I read how anchoring from the stern in hurricane force winds was a good way to stop a sloop from heeling and, perhaps more importantly, stop the boat from riding back and forth.

Having experienced the latter, albeit on a mooring, I’d be very tempted to anchor stern on in similar conditions.

 

[Neeves]

A remark made earlier

Why is anchoring described as so much fear.

I wondered how people learnt to anchor?

I think some of us learnt the hard way and errors in technique were only exposed at 2am in the rain - we learnt by our own mistakes. Some were lucky - and grew up with parents who had yachts. Many or 'our' parents never even dreampt of sailing - it was enough to keep the car clean, mow the lawn and worry about 20% interest rates - yachts were for the Hoi poloi. It never crossed my consciousness to think of vessels larger than 14' - until I moved to Hong Kong. Do sailing schools teach the art (and science) of anchoring? Dinghy sailors know how to trim sails - but anchoring.... and we suggest to neophytes looking for experience - join as crew on the weekend racing yachts - again you learn about sail trim - and if you absorb it all - are a very competent sailors - but anchoring....?

Anchoring can be one of the great pleasures of yacht owner ship - but get it wrong and you learn a single lesson (maybe if you can identify what went wrong) or not. Anchoring failures are very difficult to define without input from someone more experienced - and if you are learning from your mistakes - experience in the early days is a valuable but unknown commodity.

I know some very competent sailors, they win races - but they never anchor. They love being on their yacht, they can spend the weekend with their wife, family, friends - but on a courtesy mooring.

They are not easily scared - but they find anchoring ... unreliable.

They are not members of forum, so no fear engendered - but its a novel experience they do not embrace.


I have read through the whole thread but am not going to do so again - to identify the individuals that have a desire to learn more about the science or art of anchoring and their desires are to be commended. Equally describing anchoring experiences is educational, even supposed experts are always willing to learn, every event is different - but we only learn if full detail is given.

I know some find anchoring threads repetitive, boring and tedious - but there are people out there wanting (or needing) the experiences and lessons.

Jonathan

 

[NormanS]

I suspect that you don't really mean the Hoi Poloi. ?

 

[Tranona]

Do sailing schools teach the art (and science) of anchoring? Dinghy sailors know how to trim sails - but anchoring.... and we suggest to neophytes looking for experience - join as crew on the weekend racing yachts - again you learn about sail trim - and if you absorb it all - are a very competent sailors - but anchoring....?

Yes, part of the RYA syllabus, along with picking up a mooring buoy and berthing in a marina. How much time is devoted to each of these will depend on where the course takes place. For example in the Med a lot of time will be devoted to backing up to a wall or into a stern to berth as this is the dominant method of berthing. Equally in the UK more time may be devoted to anchoring in tidal waters with emphasis on depths and changes in direction of flow.

For most people in the UK though, anchoring is really not a big deal as in the popular sailing locations holding is good and extreme weather conditions rare (and usually avoidable). As I suggested earlier it is mainly when people start sailing in "alien" environments that they discover UK anchoring techniques and gear are inadequate so look for improvements and changes. This search inevitably challenges accepted orthodoxies.