Anchor design and misnomers

[Cotemar]

Originally Posted by Astrid

And let's not forget the important patent infringement search to make sure your design or elements thereof do not infringe on someone elses patents.

Absolutely, that research is done in the design phase upfront.

[nigel1]

Originally Posted by noelex 77

The difficulty is that the roll bar anchors do not fit many boats. Given the very high cost of the Spade outside France (and Europe in general) the market is struggling for a non roll bar anchor that performs reasonably. The Spade is tightly patented which makes copies unlikely.

Cost of a Spade anchor is significantly higher in Europe compared to others.
Looking at one suppliers website, and prices in UK Sterling
27Kg Manson Boss £575
27Kg Manson Supreme £500
20Kg Spade £585
25Kg Spade £770

Any one using the Boss anchor??

[Kettlewell]

Considering the Spade came first, you don't see nearly as many here in the USA as you do Rocnas and Supremes. A 25 kg Spade lists for $999 on the web over here, which I believe translates to about £662 UK Sterling. In the Defender catalog the 27 kg Manson Supreme goes for $665 and the 25 kg Rocna for $560. The 27 kg Boss is $800. I haven't yet seen a Boss in the wild except hanging in the Manson booth at the boat show.

[cwyckham]

Originally Posted by Cotemar

Here is an illustration of how the seabed forces act on modern day anchor profiles.

Where did you find this? You have presented a lot of material in this thread as fact, but I don't know if it represents actual soil science or your (or a biased anchor manufacturer's) attempt to understand.

As others have said, I think that we can basically call any anchoring substrate incompressible. However, it is absolutely correct to talk about "compressive forces" if you want to use that term. Shear forces may also be important. However, I am not a soil scientist, so I really don't know.

My gut feel is that convex anchors may actually be more effective if they can be convinced to dive, while concave anchors may be more effective if only skimming the surface.

The only direction that the substrate can move is upwards. Sideways force must be absorbed into the effectively infinite, incompressible substrate. If one could somehow take away the surface effect and bury a wedge shape very deeply into the substrate, then the convex wedge shape will put large compressive forces on the substrate on either side of it. The forces will be smoothly distributed in a bulb shaped area on either side of the wedge. The substrate can't move out of the way as it is incompressible and the holding will be excellent.

If we do the same experiement with a concave anchor, then there will be no compressive forces out to the side, only on a thin column the same width as the anchor itself. Again, the holding will be good since the substrate is incompressible, but if we assume minimal shear strength, then the shape and distribution of the substrate providing the resistance is very different than for the wedge. It is a narrow area directly in front of the anchor with very distinct edges.

Once we take this experiement closer to the surface, then you have the more realistic case and can see the effect. The convex wedge shape will push both sideways and upwards. If it doesn't dive, it will just lift up the substrate and plough. If it dives, then it will hold very well.

The convex anchor will either lift up a divet of substrate or it will dive. If it dives, then it will hold well. If it stays near the surface, then it is relying on the size of the column of substrate in front of it and on the shear strength of the substrate preventing a divet from being pulled out. Surface area will be key.

Anyway, I think it's safe to say that nobody on this thread, and maybe not very many people actually in the anchor industry are doing realistic models of actual substrate behaviour. It is a tough thing to model. Simplified diagrams showing which way the forces are pointing on the anchor itself probably don't help much since it is the behaviour of the substrate that determines whether the anchor tears through or stays fast.

I think diving ability is probably much more important than other shape characteristics in the end, and I'm not sure what would determine which anchor dives well and which doesn't. I do agree that a hoop would often limit the depth of dive, though.

[cwyckham]

Originally Posted by nigel1

Cost of a Spade anchor is significantly higher in Europe compared to others.
Looking at one suppliers website, and prices in UK Sterling
27Kg Manson Boss £575
27Kg Manson Supreme £500
20Kg Spade £585
25Kg Spade £770

Any one using the Boss anchor??

I'm using the 45# Boss and I can say that it sets well and holds fast with maximum reverse revs. I can't tell you much else beyond that as we haven't used it in enough rough conditions. It sure sets nicer than a 35# CQR, though.

[JonJo]

Originally Posted by GordMay

Or perhaps a McCarron-Stewart-Lyall shank

The Delta Anchor was patented (# 5138967*) by Philip F. McCarron, James W. Stewart, and Gordon M. Lyall (of Simpson-Lawrence Ltd) in 1992.

* ➥ Patent US5138967 - Marine anchor - Google Patents

Note the patent citations (prior art) & references (to Delta).

GordMay,

You are very correct, Gordon was the technical Director of Simpson Lawrence at the time and led the development team.

A 'Lyall shank' trips off the tongue quite nicely, 'McCarron, Stewart, Lyall shank' does not have such an easy ring - though does do credit to the other patent holders.

Jonathan

[downunder]

Originally Posted by cwyckham

Where did you find this? You have presented a lot of material in this thread as fact, but I don't know if it represents actual soil science or your (or a biased anchor manufacturer's) attempt to understand.

As others have said, I think that we can basically call any anchoring substrate incompressible. However, it is absolutely correct to talk about "compressive forces" if you want to use that term. Shear forces may also be important. However, I am not a soil scientist, so I really don't know.

My gut feel is that convex anchors may actually be more effective if they can be convinced to dive, while concave anchors may be more effective if only skimming the surface.

The only direction that the substrate can move is upwards. Sideways force must be absorbed into the effectively infinite, incompressible substrate. If one could somehow take away the surface effect and bury a wedge shape very deeply into the substrate, then the convex wedge shape will put large compressive forces on the substrate on either side of it. The forces will be smoothly distributed in a bulb shaped area on either side of the wedge. The substrate can't move out of the way as it is incompressible and the holding will be excellent.

If we do the same experiement with a concave anchor, then there will be no compressive forces out to the side, only on a thin column the same width as the anchor itself. Again, the holding will be good since the substrate is incompressible, but if we assume minimal shear strength, then the shape and distribution of the substrate providing the resistance is very different than for the wedge. It is a narrow area directly in front of the anchor with very distinct edges.

Once we take this experiement closer to the surface, then you have the more realistic case and can see the effect. The convex wedge shape will push both sideways and upwards. If it doesn't dive, it will just lift up the substrate and plough. If it dives, then it will hold very well.

The convex anchor will either lift up a divet of substrate or it will dive. If it dives, then it will hold well. If it stays near the surface, then it is relying on the size of the column of substrate in front of it and on the shear strength of the substrate preventing a divet from being pulled out. Surface area will be key.

Anyway, I think it's safe to say that nobody on this thread, and maybe not very many people actually in the anchor industry are doing realistic models of actual substrate behaviour. It is a tough thing to model. Simplified diagrams showing which way the forces are pointing on the anchor itself probably don't help much since it is the behaviour of the substrate that determines whether the anchor tears through or stays fast.

I think diving ability is probably much more important than other shape characteristics in the end, and I'm not sure what would determine which anchor dives well and which doesn't. I do agree that a hoop would often limit the depth of dive, though.

+1

Very good analysis makes a lot of sense to me.

Agreed the simplified diagrams that you speak of do not explain the relationship of anchors to the substrate. I also believe soil science holds the key.

Cheers

[Kettlewell]

The Vryhof manual referenced in the BIB post has some interesting information on holding power and soil failure at maximum holding power. Take a look at page 27. Their bottom line seems to be that the more streamlined an anchor is the better, for deeper diving, which is what they are touting about their anchors. The deeper the dive the better for holding power.

[JonJo]

Some superficial differences between a Delta and Excel.

The Excel is 'less' convex
The Excel has a sharper (ASTM 514) toe
The Excel has a turned down toe
The Excel has a protruding sole
The protruding sole allows the ballast weight to be carried nearer the toe
The protruding sole allows the Excel to turn more easily in a wind shift
The Excel has a perforated fluke - the perforations are not designed to be simply decoration
The Excel has a different throat angle
The Excel carries its shank attachment point in a different location to the Delta, impacting balance.
The fluke has a protruding sharpened skirt
The Excel has skids
The Excel contains no lead
The Excel shank is ASTM 514
The shank is slotted into the fluke and welded top and bottom, so not butt welded.

As to specific differences you would need to ask Anchor Right

[JonJo]

+1

You have just proved that a thousand words is worth much more than a picture!

Originally Posted by cwyckham

Where did you find this? You have presented a lot of material in this thread as fact, but I don't know if it represents actual soil science or your (or a biased anchor manufacturer's) attempt to understand.

As others have said, I think that we can basically call any anchoring substrate incompressible. However, it is absolutely correct to talk about "compressive forces" if you want to use that term. Shear forces may also be important. However, I am not a soil scientist, so I really don't know.

My gut feel is that convex anchors may actually be more effective if they can be convinced to dive, while concave anchors may be more effective if only skimming the surface.

The only direction that the substrate can move is upwards. Sideways force must be absorbed into the effectively infinite, incompressible substrate. If one could somehow take away the surface effect and bury a wedge shape very deeply into the substrate, then the convex wedge shape will put large compressive forces on the substrate on either side of it. The forces will be smoothly distributed in a bulb shaped area on either side of the wedge. The substrate can't move out of the way as it is incompressible and the holding will be excellent.

If we do the same experiement with a concave anchor, then there will be no compressive forces out to the side, only on a thin column the same width as the anchor itself. Again, the holding will be good since the substrate is incompressible, but if we assume minimal shear strength, then the shape and distribution of the substrate providing the resistance is very different than for the wedge. It is a narrow area directly in front of the anchor with very distinct edges.

Once we take this experiement closer to the surface, then you have the more realistic case and can see the effect. The convex wedge shape will push both sideways and upwards. If it doesn't dive, it will just lift up the substrate and plough. If it dives, then it will hold very well.

The convex anchor will either lift up a divet of substrate or it will dive. If it dives, then it will hold well. If it stays near the surface, then it is relying on the size of the column of substrate in front of it and on the shear strength of the substrate preventing a divet from being pulled out. Surface area will be key.

Anyway, I think it's safe to say that nobody on this thread, and maybe not very many people actually in the anchor industry are doing realistic models of actual substrate behaviour. It is a tough thing to model. Simplified diagrams showing which way the forces are pointing on the anchor itself probably don't help much since it is the behaviour of the substrate that determines whether the anchor tears through or stays fast.

I think diving ability is probably much more important than other shape characteristics in the end, and I'm not sure what would determine which anchor dives well and which doesn't. I do agree that a hoop would often limit the depth of dive, though.

[JonJo]

Originally Posted by estarzinger

On the shanks, the delta shank is "self launching", which I suspect is why rocna copied it. Self-launching is an important feature in the motor boat segment (which by the way is bigger than sailboat anchors). quote

One wonders - the Bugel is also self launching. Why make an identical copy of something you do not need when the Bugel shank would be easier and cheaper to cut?



----------------------------------

Evan said:

On "Copies" . . . "Improved copies". . . And "developments"

True original creative ideas are very rare. Most anchors are developments of prior designs. quote

Could not agree more.

Evan further said

Anyone honest will agree the rocna fits in that development category. They very clearly took ideas from quite a number of prior anchors and combined them. However, it is also clearly not a "copy" of any one as it differs in very significant and easily describable ways from any anchor that came before (the rocna vs supreme "copy" question is more complicated as you well know). The rocna flukes alone are very different from the spade flukes in obvious and explainable ways (no tip weight and much greater surface area). So the rocna is/was a development quote

If you take a plan view of a Rocna and Spade and examine the fluke you will find the toe sections are the same angle, the angle between toe section and rear section is the same and occurs at the same distance from the toe. I assume this is simply coincidence? The Rocna has a ballasted toe, unless the thickened plate at the toe is there purely for decoration.

On copies - its Rocna themselves who made a marketing ploy out of copies. If they find themselves in the firing line they only have themselves to blame. Personally, and clouding my judgement, I find a manufacturer knocking a competitor at best distasteful especially when they spend so much time doing so.

Evan said:

My personal conclusion is that if those are the two significant differences (Excel)vs the delta then its clearly an "improved delta copy" and I will reserve judgement on how improved (over the wide range of possible bottoms) until I see some more objective and independent data. quote

There have been innumerable independent positive comments on the Excel, how many do you need - or do you simply not believe anyone who owns an Excel. I take your comments as honest - why not extend the same courtesy to owners of Excels?

Finally Evan said

I honestly don't understand the defensiveness and hostility that is coming back.

Primarily because you comment first off was 'it looks like a Delta' which sounded disparaging. There have been so many positive comment on the Excel, which you will have and been well aware of, yet despite the contrast of positive over Excel and often negative over Delta your comment is - they look the same! You are effectively calling us liars - no wonder we seem resentful.

As I said we take your comments as honest and educational - simply extend that courtesy to us and we'll be less defensive and less hostile.

[Factor]

I think most of cotemars posts prove my point about didactic reasoning, and certainly the overall view about religious fervour in anchor posts. He clearly likes his Rocna, and thats good. So much so that he uses words and pictures off the website of his messiah, Peter Smith the original Rocna man. The image below is straight off Smith's web site. Nothing wrong with that - but perhaps a declaration or acknowledgement would be appropriate.

Please don't think I am dissin the Rocna, clearly a wonderful anchor let down by the behaviour of Craig Smith and the dodgy manufacturing issue. But both those things were overcome. It had a failing however, reduction of ability to reset if clogged. And that lead me to search for something else.

[Delfin]

Originally Posted by JonJo

Some superficial differences between a Delta and Excel.

The Excel is 'less' convex
The Excel has a sharper (ASTM 514) toe
The Excel has a turned down toe
The Excel has a protruding sole
The protruding sole allows the ballast weight to be carried nearer the toe
The protruding sole allows the Excel to turn more easily in a wind shift
The Excel has a perforated fluke - the perforations are not designed to be simply decoration
The Excel has a different throat angle
The Excel carries its shank attachment point in a different location to the Delta, impacting balance.
The fluke has a protruding sharpened skirt
The Excel has skids
The Excel contains no lead
The Excel shank is ASTM 514
The shank is slotted into the fluke and welded top and bottom, so not butt welded.

As to specific differences you would need to ask Anchor Right

The question of patents and quantitative differences between a Delta and an Excel is interesting, I guess. But it does seem that those differences, whether patented or not or obvious or not are somewhat secondary to performance in the real world. If someone has a mediocre report on an Excel I would like to hear it, I just haven't yet. If someone has a mediocre report on a Delta it's no news flash - there are lots of them. Mediocre doesn't mean inadequate, just that if you have a choice, you should be informed on the performance differences. Unfortunately, because the Excel is new, and native to Oz, and lacks North American distribution worthy of the name there isn't a lot of data. The attached provides some from Practical Sailor. This was on veer testing, and would seem to support the proposition that the Delta is not as good an anchor as the Excel, even if they look alike.

Maybe the difference is due to greater surface area - here an 11# Excel has more surface area to its weight than a 14.7# Delta, as well as the ability to set and reset in half to a third the distance. Beats me, and if you want to call the Excel an improved Delta, feel free. The improvement seems obvious both from user experience and datasets like this.

[Kettlewell]

Yeah, but the 9.4 lb Kobra looks to be just as good as the Excel at a lot less cost! These very small differences in a very limited number of tests in a specific location don't tell us much. The Kobra looks very Deltaesque too.

[Andrew Troup]

Originally Posted by estarzinger

Hey Gord, you are excellent at this google search stuff and I have a little challenge or you that would help the thread. I got a pm from Rex Francis (owner/designer at anchor right of the Excel). Basically he said that all I had to do was an easy google patent search and all our questions about the distinctive features of the Excel (vs the delta) would be answered. I did that, and did find some patents under his name, but none appeared relevant to the Excel. He unfortunately does not list any patents numbers on his website, nor included any in his pm to me. Can you find any patents that list the specific unique patented features of the Excel?

Evans and Gord

To save Gord's exceptional skills for another day,
I think this is the patent you're looking for:

Patent US8205569 - Anchor - Google Patents

It seems to be the Excel anchor, from a quick perusal of the drawings

It references the Delta patent, so in order to be granted, I guess the patent examiners were convinced that the improvements were substantial and non-obvious.

However it's a bit of a lottery, in that they are generalists rather than having specialised knowledge of anchor design.