Anchor size. I know. Sorry.

[geem]

No, this is how the manufacturers’ table works (there are some rare exceptions). This is definitely not something I agree with.

For example, for your sized 44 Ketch, the anchor manufacturers recommend a 16kg Delta or a 16kg CQR, jump to better anchor designs, and overall the size goes significantly up rather than down.

Rocna recomend. 25Kg weight anchor, Spade a 20kg, and Ultra a 27kg model.

The above are the recommendations for steel or stainless steel models. Comparing like for like. The manufacturers’ recommended size for aluminium anchors will, of course, be quite different as you would expect.

I dont recognise your figures. Spade recommended a 30kg for my 18t boat. Delta say 25kg. Ultra say 35kg. Rocna say 35kg

 

[noelex]

I dont recognise your figures. Spade recommended a 30kg for my 18t boat. Delta say 25kg. Ultra say 35kg. Rocna say 35kg

I used your yacht’s listed displacement on salboatdata.com of 14,500 kg (32,000 lbs) for your 44 yacht when determining the recommended anchor size. If 18t displacement is used, it further proves the trend as the recommended sized jumps for the better anchors as you indicate.

Spade to 30kg (although it should be noted this model is suitable for yachts up to 66 feet according to Spade), Rocna 33kg and Ultra 35kg. Delta and CQR anchors stay at 16kg further proving the point.

I am not sure where you determined a recomended Delta size of 25kg for a 44 foot yacht, but even if this is correct it is still one size lighter than the recommendations for the significantly better quality anchors. Showing how anchor sizing tables make little practical sense in the real world.

However, below is the official Lewmar sizing table for the Delta anchor (the CQR table is also very similar). Using this for a 44 foot yacht most people are going to select a smaller Delta than 25Kg ( perhaps a very small 16kg?) if they are trying to follow the manufacturer’s table especially if they believe the (incorrect ) warnings that are frequently voiced on this forum to "never oversize their anchor".

 

[Dockhead]

Many Viking owners, numbering thousands, and a summary of the Penope work suggest a lighter anchor is more than adequate. The Viking recommendations are for physical size, not weight, and the recommended anchor is thus lighter (and bigger in area).

For Viking hold per kg is simply not accurate when comparing different designs. Their philosophy is a combination of design, stronger steel, greater area (engendering better hold) and thinner steel sets more quickly. Many of the attributes of Fortress, without Fortress' specific negative characteristics.

You don't miss a chance to plug Viking anchors, do you?

Again, this thread is not about comparing different anchor designs. It's about anchor SIZE, between the same design. The OP was concerned he had bought too small an anchor, and was asking for advice.

For the record, everyone agrees, and it's very obvious, that some anchor designs don't use weight, but rather fluke sharpness and geometry, to get the anchor set. This has been a thing since WWII, when the Danforth was specifically designed as a light but effective anchor for seaplanes, for whom weight was an even bigger issue than for catamarans.

Back to the original subject -- Steve of Panope, whom you mention, who has done probably the most extensive yacht anchor tests ever done, uses an anchor three sizes larger than the manufacturer's recommendation, on his own yacht. Not because of weight, but SIZE.

 

[Neeves]

You don't miss a chance to plug Viking anchors, do you?

You don't think supporting a manufacturer in Kiev making a highly rated marine product merits support....what do you do?

The owner of Viking read the article on one of my investigations on anchor performance, America's Practical Sailor, and followed my conclusions and increased the hold of the Viking anchor by about 50%.

Few of us can help Ukrainians - I'm doing my little bit. The owner of Viking asked if he could use my design of the Boomerang and my Bridle plate for multihull snubbers - I was happy to help and gave him access, free of charge (and I make no money from my action). Another anchor maker copied the design of the Boomerang, it WAS published open source (in Australia's Cruising Helmsman), and called it his 'innovative design'.

Jonathan

 

[zoidberg]

Has it occurred to anyone that this variance in 'recommended weights' could be down to Marketing?

 

[14K478]

Has it occurred to anyone that this variance in 'recommended weights' could be down to Marketing?

Marketing? For anchors? Surely not!!

 

[Dockhead]

Not sure you have been round here long enough in these debates to know that there are indeed many who do argue (with fervour) "bigger and heavier is better". However maybe the weight of theoretical and empirical evidence, or number of people who have challenged this thinking has persuaded them not to engage or more charitably have actually changed their minds.

This view has now been replaced by some who use a milder form of "fit as big an anchor as you can handle". Why? when the manufacturer has recommended a size for your boat and provided guidance about circumstances where going up a size may be a consideration. If like the majority of boats yours fits well within the size band and if already built has windlass, chain and bow fittings matched to the recommended size why change? There is no benefit as it is unlikely that the limits of hold and strength of chain will ever be reached.

It is not difficult to explain the origin of the heavy chain and oversize anchor mantra - as I (and others) have explained it was based on the type of anchors and chain available up to about 25 years ago and therefore many learned their anchoring techniques from their early days. Many also still use that outdated equipment so for them the mantra still holds true. All the developments in anchors chain windlasses bow fittings etc have been based on reducing weight and increasing power and strength to achieve the same or better performance in a wider range of conditions. Couple that with the increase of data and in use experience of anchors it is easier to determine when your boat and pattern of sailing/anchoring is at the margins for a recommended size range/usage and going up a size might be appropriate. My boat for example is at the upper end (in terms of displacement, but not hull length) for a 10kg Epsilon with 6mm chain. For my kind of gentle cruising with a lot of anchoring in sheltered conditions it is more than adequate - even overkill. If however I wanted to go off on more adventurous cruising as many owners of the same design have done I might well consider going up a size (a 50% increase based on weight!) but that would mean changing chain, either 8mm which would mean a new gypsy or stronger) and possibly modifications to the roller and its mounting to retain self stowing. Possible dilemma for the next owner.

Sailors have been arguing about anchors since Jason threw a perforated stone out of the Argo, no doubt.

I've never heard anyone argue that heavier chain results in more secure anchoring. I'm not saying no one has said it, but I don't recall hearing this argument. It's well known that holding power of anchors is a function of the mass of seabed engaged by the anchor, and that has nothing to do with the chain. Dashew believed that the chain should be as light as possible, in fact, so that the total mass of the ground tackle could be concentrated in the anchor.

Sizing of anchors is a completely different question. Totally agree with you that different use cases result in different sizing needs, and people know from their own experience what works for them.

I'd just like to point out, however, that the numbers show that the holding power of a given anchor falls off remarkably steeply with bottom quality, and scope, and the NEED for holding power goes up with the square of the wind speed. So an anchor which is perfectly adequate in average conditions can very suddenly become inadequate with the wrong combination of wind speed, wave action (dynamic forces count too), bottom quality, and scope. You need 7x (!) the size to develop the same holding force in a poor bottom, compared to an excellent one, using the same type of anchor. So even decades of success with a given anchor is no guarantee that tomorrow you won't encounter just those conditions where you need more holding power. Note also the question of uncertainty -- we don't dive on our anchors in these cold waters, and so don't know for sure the quality of the bottom. A forecast gale with 40kn winds might easily produce gusts over 60kn -- been there, done that. Are you ready

I've been lying to my own anchor for a couple of weeks now, and was recently anchored in Dartmouth Harbour in bad weather. The anchorage there is very tight, and water about 9m deep at high tide. Even on 3:1 scope you will swing within a few metres of other boats, or ship buoys. I would not have risked it with the recommended size anchor for my boat, and there was no other space in the harbour those days, so I would have had to go back out to sea.

 

[Neeves]

Has it occurred to anyone that this variance in 'recommended weights' could be down to Marketing?

The market buys anchors by weight. A side effect is that a heavier anchor, of the same design, must be better.

Some manufacturers define surface area - but if there is surface area within promotion its low key.

Weight is King

Jonathan

 

[Dockhead]

You don't think supporting a manufacturer in Kiev making a highly rated marine product merits support....what do you do?

The owner of Viking read the article on one of my investigations on anchor performance, America's Practical Sailor, and followed my conclusions and increased the hold of the Viking anchor by about 50%.

Few of us can help Ukrainians - I'm doing my little bit. The owner of Viking asked if he could use my design of the Boomerang and my Bridle plate for multihull snubbers - I was happy to help and gave him access, free of charge (and I make no money from my action). Another anchor maker copied the design of the Boomerang, it WAS published open source (in Australia's Cruising Helmsman), and called it his 'innovative design'.

Jonathan

OK, so it's political. Got it. But Izi Kalvo lives in Israel, not Kyiv, no? And Viking Anchors is an Israeli company. The politics might cut the other way, for some of us.

There's nothing wrong with liking this or that anchor, and Steve Goodwin of Panope, one of the most important authorities on this, regards the Viking highly.

Just we were not talking about choice of anchor design at all, and arguing for a lighter anchor design in response to a question about sizing anchors just muddies the water.

 

[Neeves]

Sailors have been arguing about anchors since Jason threw a perforated stone out of the Argo, no doubt.

I've never heard anyone argue that heavier chain results in more secure anchoring. I'm not saying no one has said it, but I don't recall hearing this argument. It's well known that holding power of anchors is a function of the mass of seabed engaged by the anchor, and that has nothing to do with the chain. Dashew believed that the chain should be as light as possible, in fact, so that the total mass of the ground tackle could be concentrated in the anchor.

Sizing of anchors is a completely different question. Totally agree with you that different use cases result in different sizing needs, and people know from their own experience what works for them.

I'd just like to point out, however, that the numbers show that the holding power of a given anchor falls off remarkably steeply with bottom quality, and scope, and the NEED for holding power goes up with the square of the wind speed. So an anchor which is perfectly adequate in average conditions can very suddenly become inadequate with the wrong combination of wind speed, wave action (dynamic forces count too), bottom quality, and scope. You need 7x (!) the size to develop the same holding force in a poor bottom, compared to an excellent one, using the same type of anchor. So even decades of success with a given anchor is no guarantee that tomorrow you won't encounter just those conditions where you need more holding power. Note also the question of uncertainty -- we don't dive on our anchors in these cold waters, and so don't know for sure the quality of the bottom. A forecast gale with 40kn winds might easily produce gusts over 60kn -- been there, done that. Are you ready

I've been lying to my own anchor for a couple of weeks now, and was recently anchored in Dartmouth Harbour in bad weather. The anchorage there is very tight, and water about 9m deep at high tide. Even on 3:1 scope you will swing within a few metres of other boats, or ship buoys. I would not have risked it with the recommended size anchor for my boat, and there was no other space in the harbour those days, so I would have had to go back out to sea.

Most known anchorages are well documented with all the numerical details you could wish for. The information is freely available. If you venture to locations where the Admiralty has not published a Pilot Book it would be unusual. Unless you are exploring Hong Kong - anchorages have not changed. The detail was collated by men in boats not much different in size to our yachts. We have access to accurate weather details, not available to the stalwarts who provided the detail in the Pilot Books.

I have a 100 year old Pilot Book which contains full detail of Tasmania, (source - second hand book shop). There has been a recent cruising guide to Tasmania - there are no new anchorages. Some cruising guides seem to have lifted the script word for word from the Pilot Books

There s little reason not to have planned in advance, with a Plan B.

Jonathan

 

[Neeves]

OK, so it's political. Got it. But Izi Kalvo lives in Israel, not Kyiv, no? And Viking Anchors is an Israeli company. The politics might cut the other way, for some of us.

There's nothing wrong with liking this or that anchor, and Steve Goodwin of Panope, one of the most important authorities on this, regards the Viking highly.

Just we were not talking about choice of anchor design at all, and arguing for a lighter anchor design in response to a question about sizing anchors just muddies the water.

If you dislike thread drift you are a member of the wrong forum.


The anchors are made in Kiev, it says so, or did, on the website.

I don't pry into the detail of where people live it has no bearing on anchors. Anchor are above politics, fortunately

Indirectly I helped, in a very small way a manufacturer in Kiev to have his product defined as the best ever by a man who owns a yacht called Panope. If this puts food on the table in Ukraine I'm happy.

I don't mention Viking with any political motive but confess I quite like having my ego stroked.

Thank you for offering me another opportiunity to mention Viking (and air the Boomerang and Bridle Plate) and put more food on the table.

Jonathan

 

[geem]

I used your yacht’s listed displacement on salboatdata.com of 14,500 kg (32,000 lbs) for your 44 yacht when determining the recommended anchor size. If 18t displacement is used, it further proves the trend as the recommended sized jumps for the better anchors as you indicate.

Spade to 30kg (although it should be noted this model is suitable for yachts up to 66 feet according to Spade), Rocna 33kg and Ultra 35kg. Delta and CQR anchors stay at 16kg further proving the point.

I am not sure where you determined a recomended Delta size of 25kg for a 44 foot yacht, but even if this is correct it is still one size lighter than the recommendations for the significantly better quality anchors. Showing how anchor sizing tables make little practical sense in the real world.

However, below is the official Lewmar sizing table for the Delta anchor (the CQR table is also very similar). Using this for a 44 foot yacht most people are going to select a smaller Delta than 25Kg ( perhaps a very small 16kg?) if they are trying to follow the manufacturer’s table especially if they believe the (incorrect ) warnings that are frequently voiced on this forum to "never oversize their anchor".




View attachment 211922

Why do you get fixated on boat length. Its a very unreliable metric when selecting an anchor.( just like anchor weight) Windage and boat weight are the important metrics. Windage because it will impose a force on the boat. Boat weight because it imposes momentum. Boat length doesnt really tell you much. It would be a crude way of determining windage and weight.

 

[Dockhead]

Most known anchorages are well documented with all the numerical details you could wish for. The information is freely available. If you venture to locations where the Admiralty has not published a Pilot Book it would be unusual. Unless you are exploring Hong Kong - anchorages have not changed. The detail was collated by men in boats not much different in size to our yachts. We have access to accurate weather details, not available to the stalwarts who provided the detail in the Pilot Books.

I have a 100 year old Pilot Book which contains full detail of Tasmania, (source - second hand book shop). There has been a recent cruising guide to Tasmania - there are no new anchorages. Some cruising guides seem to have lifted the script word for word from the Pilot Books

There s little reason not to have planned in advance, with a Plan B.

Jonathan

Seabed quality is only roughly described in pilot books and other resources, and not very reliably. Seabed quality also varies locally. It's why in warm waters many good sailors dive on their anchors -- to see exactly what the anchor is in. Just because the pilot book says there's "M" or "S" in the general area you are anchored in, does not guaranty you are anchored in good holding in your particular spot. And we all know that "M" covers the widest range of different bottoms.

A full power pull in reverse is a good way to check the holding, but this is also not a guaranty, as few yachts have machinery to generate more force than 30 knots or so of wind.

I have a high-powered CHIRP sonar which I use to examine the bottoms of anchorages, but neither is this a 100% reliable method, or even 80% reliable. Good for avoiding boulders in Norway and Sweden, however, and for detecting patches of sea grass, and you can vaguely see the consistency of the of the seabed, as the sonar penetrates some distance into it.

Lastly -- Admiralty publishes no information at all about the bottoms of most yacht-sized anchorages even in the waters of highly developed and well-surveyed countries. In some developed countries, close-in waters of highly indented coasts aren't even properly charted -- Finland, which has 180,000 islands, is an excellent example. Outside of waters navigable by larger vessels, you don't even have reliable depths, much less bottom type data.

You don't have to go to the Arctic, to face significant uncertainty as to what kind of bottom you just put your hook into.

 

[geem]

Seabed quality is only roughly described in pilot books and other resources, and not very reliably. Seabed quality also varies locally. It's why in warm waters many good sailors dive on their anchors -- to see exactly what the anchor is in. Just because the pilot book says there's "M" or "S" in the general area you are anchored in, does not guaranty you are anchored in good holding in your particular spot. And we all know that "M" covers the widest range of different bottoms.

A full power pull in reverse is a good way to check the holding, but this is also not a guaranty, as few yachts have machinery to generate more force than 30 knots or so of wind.

I have a high-powered CHIRP sonar which I use to examine the bottoms of anchorages, but neither is this a 100% reliable method, or even 80% reliable. Good for avoiding boulders in Norway and Sweden, however, and for detecting patches of sea grass, and you can vaguely see the consistency of the of the seabed, as the sonar penetrates some distance into it.

Lastly -- Admiralty publishes no information at all about the bottoms of most yacht-sized anchorages even in the waters of highly developed and well-surveyed countries. In some developed countries, close-in waters of highly indented coasts aren't even properly charted -- Finland, which has 180,000 islands, is an excellent example. Outside of waters navigable by larger vessels, you don't even have reliable depths, much less bottom type data.

You don't have to go to the Arctic, to face significant uncertainty as to what kind of bottom you just put your hook into.

Northern Finland is above the Artic circle so you are pretty close!

 

[vyv_cox]

Why do you get fixated on boat length. Its a very unreliable metric when selecting an anchor.( just like anchor weight) Windage and boat weight are the important metrics. Windage because it will impose a force on the boat. Boat weight because it imposes momentum. Boat length doesnt really tell you much. It would be a crude way of determining windage and weight.

Interestingly, when the late Prof. John Knox published his guide to rode length - Chain length = (1/16) x (Yacht length) x (wind speed) x Square root of (Depth /specific chain weight) I queried exactly the same with him. His finding was that the difference in the final figure was insignificant whether using windage and boat weight v. length, whereas length was far easier to find.

 

[geem]

Interestingly, when the late Prof. John Knox published his guide to rode length - Chain length = (1/16) x (Yacht length) x (wind speed) x Square root of (Depth /specific chain weight) I queried exactly the same with him. His finding was that the difference in the final figure was insignificant whether using windage and boat weight v. length, whereas length was far easier to find.

If you take a 60ft cigar shaped speed boat compared to a 3 deck 60ft exploration type motor boat, the windage is significantly different.
Ditto a low profile sloop compared to a high windage ketch like my own. They could both be the same length but have considerable windage differences. Ditto the conciderable weight differences.
We are a liveaboard with a lot of gear. We have been lifted a couple of times on a brand new travel hoist and we weighed over 19 tonnes. We had more gear onboard than we had ever done at the time as we were about to do a teak deck replacement. All the new teak, epoxy, tools we bought, rolls of glass etc were onboard. The boat was full of fuel and water which on their own account for over 1 tonne. We normally sit at a little over 18 tonnes these days. None liveaboard boats would rarely exceed their published light displacement weight as much as liveaboards. Using the boats actually weight rather than published weight when selected an anchor is sensible as this is what will impact on the anchor performance.

 

[vyv_cox]

If you take a 60ft cigar shaped speed boat compared to a 3 deck 60ft exploration type motor boat, the windage is significantly different.
Ditto a low profile sloop compared to a high windage ketch like my own. They could both be the same length but have considerable windage differences. Ditto the conciderable weight differences.
We are a liveaboard with a lot of gear. We have been lifted a couple of times on a brand new travel hoist and we weighed over 19 tonnes. We had more gear onboard than we had ever done at the time as we were about to do a teak deck replacement. All the new teak, epoxy, tools we bought, rolls of glass etc were onboard. The boat was full of fuel and water which on their own account for over 1 tonne. We normally sit at a little over 18 tonnes these days. None liveaboard boats would rarely exceed their published light displacement weight as much as liveaboards. Using the boats actually weight rather than published weight when selected an anchor is sensible as this is what will impact on the anchor performance.

Which was exactly my comment to Prof Knox but he told me, at least for the purposes of his expression, that for practical purposes there was no difference. Although my boat was a lot smaller than yours we also carried a lot of kit, plus fixtures such as arch, solar panels, etc. We were 1.5 tonnes over the published displacement but still carried the same standard sized anchor.

 

[geem]

Which was exactly my comment to Prof Knox but he told me, at least for the purposes of his expression, that for practical purposes there was no difference. Although my boat was a lot smaller than yours we also carried a lot of kit, plus fixtures such as arch, solar panels, etc. We were 1.5 tonnes over the published displacement but still carried the same standard sized anchor.

It makes little sense. Taking things to extreme, a Pogo 44 weighs 6.3 tones. Light displacement. Our boat is 14.4t. The Pogo would never load up to the extend we would so true cruising weights may be 8t for the Pogo and 18t for us. How can length be a sensible metric

 

[Dockhead]

Northern Finland is above the Artic circle so you are pretty close!

Indeed!

But Finland, thanks to several historical accidents, has no coastline on the Barents Sea (hogged by Norway and Russia), so it's all the Gulf of Finland and the Gulf of Bothnia, in the Baltic. That is still above 60N, and the sea does freeze, but it's a developed area and hardly what anyone would call the Arctic.

 

[Dockhead]

Which was exactly my comment to Prof Knox but he told me, at least for the purposes of his expression, that for practical purposes there was no difference. Although my boat was a lot smaller than yours we also carried a lot of kit, plus fixtures such as arch, solar panels, etc. We were 1.5 tonnes over the published displacement but still carried the same standard sized anchor.

These are all very rough proxies for anchoring forces, and my guess is no one is actually wrong here.

Length alone is still order of magnitude, at least among average boats of the same type, and we're not going to get ALL that much closer than that.

Anchor makers use length, type of vessel (yacht, cat, mobo) and displacement -- that's as close as anyone can get, I'm sure!