Nomad Willy
Guru
Setting and penetrating are quite different things Marin. One is dependent on the other of course.
Chesapeake Anchor Holding Power Test
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You said the rollbar doesn't help with penetration. That's exactly what it's there for. Review the video as you clearly don't understand how the rollbar anchor works and what the job of the rollbar is. It's to force the fluke to PENETRATE the bottom. Once it has penetrated the bottom, the shape of the fluke and and geometry of the anchor then turn it which makes the anchor SET.
It's a very simple and brilliant design which I understood the moment I saw the demo of how it works, and it's why we bought one.
ranger58sb
Guru
Without regard to cleanliness...
I wonder if a concave design eventually collects enough weight toward the back of the fluke such that the tip no longer points downward... so the direction of pull becomes more or less horizontal from that point on?
Whereas a convex surface maybe never collects enough weight toward the back so that the tip always still points downward... and the direction of pull continues to dig deeper?
Not arguing, simply thinking (typing) out loud, as it were.
The Delta design is a convex flute, and our experience with it was generally positive. In soupy mud, I think I remember the whole shank showed evidence of having been buried... suggesting it at least keep digging further downward until we finally gave it a rest.
That was the time we did drag, during a raft-up when I had about 10 sailboats on our 35-lb Delta... Don't know overall weight, but we were a 14K-lb 34' powerboat, the shortest sailboat was about 25,' and most were in the neighborhood of 34-38'. Tidal current and a light breeze interrupted our happy hour for a bit, but one of the sailors came to the rescue... with a bigger/heavier CQR. The guys who came back in the dinghy from setting the replacement were pretty much all covered in muck. Yuck! Glad they offered to solve the issue, so I didn't have to go out there
In any case, I didn't fault the anchor; I think we just overloaded it beyond it's size/weight capabilities. And I always appreciated the "no moving parts" design.
Seems to me the Sarca Excel anchor looks similar to a Delta?
-Chris
Fortress or Danforth can NOT lay on their side... and ... there is NO upside down. Flukes did and dig. Fortress' additionally capable 45 deg. shank to fluke angle should make mud bottom setting even better, overall. 
Jus sayen!
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Ah, apologies, I missed that one. Sounded like a misremembered version of psn's. Actually his, as I quoted, is nearer the truth, I think you would agree..?
If the roll bar contributed to setting, after the anchor had been righted, then Peter Bruce who invented the roll bar would have used it himself. If the roll bar aided penetration and setting every anchor would have one. Take the roll bar off a Mantus, arrange that its on the seabed correct way up (it will not self right without the roll bar) and it sets more deeply and with a greater hold. I've tried it and Mantus said so (and they ought to know).
The roll bar resists penetration - its a hindrance and is about 10% of the surface area of the fluke (depends on the roll bar - some are smaller) edit - all anchor makers reduce anything that retards penetration - which is why we have thin shanks, why Fortress chamfer their shanks, why the Danforth HT and XYZ came with wire traces etc.
What a load of rubbish some people suggest
The roll bar resists penetration - its a hindrance and is about 10% of the surface area of the fluke (depends on the roll bar - some are smaller) edit - all anchor makers reduce anything that retards penetration - which is why we have thin shanks, why Fortress chamfer their shanks, why the Danforth HT and XYZ came with wire traces etc.
What a load of rubbish some people suggest
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Nomad Willy
Guru
So there you have it. "Remove the RB and achieve better penetration" the RB is like a starter on an engine. Once the engine's started it's just excess weight. Kick start motorcycles were great. MUCH smaller battery and no starter motor.
An anchor that uses weight for orientation (like a Delta or Spade) dosn't pay the RB drag penalty. Funny thing though that the Supreme and Rocna outperform the Delta and Spade. So obviously the RB ain't all bad.
Art the stock causes drag just like the roll bar.
There's no engine that's 100% efficient and there's no anchor that can hold a boat, set, pitch down advantageously, break out when asked ect ect. But we can do better than a RB anchor. But I think the best anchor will not excel in any one category but achieve excellent results more of the time in all categories. A Navy anchor would do that except that holding power would probably be lacking. How much it would lack is unknown among most or all of us. But then if one overlooked weight (as many here do re chain) the perfect anchor is already here.
The Mantus has a bigger RB than the Rocna or Supreme and if it performs as well (or better) that would be another indication that my interference drag theory playing a big role in holding power is correct.
An anchor that uses weight for orientation (like a Delta or Spade) dosn't pay the RB drag penalty. Funny thing though that the Supreme and Rocna outperform the Delta and Spade. So obviously the RB ain't all bad.
Art the stock causes drag just like the roll bar.
There's no engine that's 100% efficient and there's no anchor that can hold a boat, set, pitch down advantageously, break out when asked ect ect. But we can do better than a RB anchor. But I think the best anchor will not excel in any one category but achieve excellent results more of the time in all categories. A Navy anchor would do that except that holding power would probably be lacking. How much it would lack is unknown among most or all of us. But then if one overlooked weight (as many here do re chain) the perfect anchor is already here.
The Mantus has a bigger RB than the Rocna or Supreme and if it performs as well (or better) that would be another indication that my interference drag theory playing a big role in holding power is correct.
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Quote:
Originally Posted by Marin
The issue of convex vs. concave is purely physics or geometry or whatever science it is. A concave survace concentrates material--- be it mud, air, or dirt in a ditch-- by forcing it toward the center of the suface. In the case of an anchor, a concave fluke surface will concentrate the bottom material toward the center of the fluke, which will increase the fluke's resistance to the direction of pull. It's why the concave surface of a shovel picks up and holds more dirt than the convex side.
A convex surface sheds material.
Rex Wrote:
Yes well I am not going to convince you but there is no harm with facts, concave –shovel is for removal of substrate, cuts in –cuts out and retains, add a roll bar, you now have a sausage maker, so well compressed it then becomes a resistance for hold, not lock up, no further depth.
A well designed shallow convex cuts in--- compressors, compression builds with depth, depth is encouraged with further load, plowing is not a result of convex, “ plowing is simply a result of directional concave sheers” we do not have plow sheers.
Marin we are not comparing substrate to air—water—air craft, we are talking substrate where speed has a minor effect as compared to how the above reacts.
Ranger42C Wrote:
Seems to me the Sarca Excel anchor looks similar to a Delta?
Rex Wrote:
The Excel is based on the same principle as the Super Sarca, convex body – turn down toe –cutting edges all round-- A single plain flukes that does not plow, whilst they look similar to the Delta they are two very different breeds, more importantly the Excel now over five years is building a remarkable reputation, I say remarkable as it has been a short time since its release, not just in holding power, but as an improved anchor design for many substrate types.
But you are right ranger42C they do look very similar unless you know what to look for.
HopCAR:
Sorry I cannot deliver you free anchors, if I did you would have to ban psneeld, seems all too difficult to some so we will carry on regardless supplying anchors direct at your distributors cost to offset freight, it may seem odd to operate this way, then again customers are so passionate about anchor technology there seems to be no length with some as to how far they are prepared to go, then again the landed cost with our discount works out pretty good for most.
Regards Rex.
Originally Posted by Marin
The issue of convex vs. concave is purely physics or geometry or whatever science it is. A concave survace concentrates material--- be it mud, air, or dirt in a ditch-- by forcing it toward the center of the suface. In the case of an anchor, a concave fluke surface will concentrate the bottom material toward the center of the fluke, which will increase the fluke's resistance to the direction of pull. It's why the concave surface of a shovel picks up and holds more dirt than the convex side.
A convex surface sheds material.
Rex Wrote:
Yes well I am not going to convince you but there is no harm with facts, concave –shovel is for removal of substrate, cuts in –cuts out and retains, add a roll bar, you now have a sausage maker, so well compressed it then becomes a resistance for hold, not lock up, no further depth.
A well designed shallow convex cuts in--- compressors, compression builds with depth, depth is encouraged with further load, plowing is not a result of convex, “ plowing is simply a result of directional concave sheers” we do not have plow sheers.
Marin we are not comparing substrate to air—water—air craft, we are talking substrate where speed has a minor effect as compared to how the above reacts.
Ranger42C Wrote:
Seems to me the Sarca Excel anchor looks similar to a Delta?
Rex Wrote:
The Excel is based on the same principle as the Super Sarca, convex body – turn down toe –cutting edges all round-- A single plain flukes that does not plow, whilst they look similar to the Delta they are two very different breeds, more importantly the Excel now over five years is building a remarkable reputation, I say remarkable as it has been a short time since its release, not just in holding power, but as an improved anchor design for many substrate types.
But you are right ranger42C they do look very similar unless you know what to look for.
HopCAR:
Sorry I cannot deliver you free anchors, if I did you would have to ban psneeld, seems all too difficult to some so we will carry on regardless supplying anchors direct at your distributors cost to offset freight, it may seem odd to operate this way, then again customers are so passionate about anchor technology there seems to be no length with some as to how far they are prepared to go, then again the landed cost with our discount works out pretty good for most.
Regards Rex.
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Delfin
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Whatever Smith said for marketing purposes to flog his product, the utility of the roll bar on a Rocna or a Mantus or a Supreme is because without it, the anchor is useless as it as likely to glide along the bottom upside down as in the attitude that will dig in. The Sarca Excel and Ultra achieve their results without a roll bar through a drooping tip and a lot of weight in the tip. When I lay my Ultra on the dock, it immediately flops into the optimum penetration position. It is completely unstable in any other position and I assume the Excel would be as well. Had I a Rocna without a roll bar, it would be perfectly stable upside down. As Rex notes, the disadvantage of the roll bar is that it prevents the anchor from penetrating as deeply as it would otherwise, and can load up to the point where the tip of the anchor rotates upwards, losing all holding power. The Super Sarca seems to avoid this both with its convex design that moves material to the sides, not concentrating it to pile up against the roll bar, but also by making the roll bar so thin it presents little resistance to digging in.
As a practical matter, the roll bar also adds resistance to dragging even if it prevents digging in as deeply, but this disadvantage likely disappears in high wind loads. Other digging anchors, like the Fortress will dig in so deeply under such conditions that they may be very hard to retrieve, which might be inconvenient but hardly could be said to be a disadvantage to an anchor if staying put is the primary objective.
Like everything else in engineering, there are trade offs in anchor design. To assert that roll bar anchors are some kind of pinnacle of anchor design is silly, since they are good in some ways, deficit in others and IMO ultimately the deficiencies outweigh the advantages, at least in a world where better all around anchors are readily available.
As a practical matter, the roll bar also adds resistance to dragging even if it prevents digging in as deeply, but this disadvantage likely disappears in high wind loads. Other digging anchors, like the Fortress will dig in so deeply under such conditions that they may be very hard to retrieve, which might be inconvenient but hardly could be said to be a disadvantage to an anchor if staying put is the primary objective.
Like everything else in engineering, there are trade offs in anchor design. To assert that roll bar anchors are some kind of pinnacle of anchor design is silly, since they are good in some ways, deficit in others and IMO ultimately the deficiencies outweigh the advantages, at least in a world where better all around anchors are readily available.
eyschulman
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If the roll bar has air or flotation it could serve two purposes. #1 keep the anchor from dragging upside down or on its side. The air could also cause the point to tilt down and help with setting
Northern Spy
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Nomad Willy
Guru
eyschulman,
Ever heard of the anchor called "Hydro Bubble"?
Now and then they delivered great performances.
They relied on a plastic air chamber high on the anchor to keep it right side up. The opposite of weight in the tip of a fluke. But I'm not shocked at their failure as all other anchors use weight as a positive force. Would be hard for an anchor to set w an air chamber lifting it up.
Ever heard of the anchor called "Hydro Bubble"?
Now and then they delivered great performances.
They relied on a plastic air chamber high on the anchor to keep it right side up. The opposite of weight in the tip of a fluke. But I'm not shocked at their failure as all other anchors use weight as a positive force. Would be hard for an anchor to set w an air chamber lifting it up.
Great Laker
Senior Member
One thing occurs to me that I have not heard considered, but I may have missed it here or in a different thread.
It seems reasonable that the deeper the anchor gets, the more compact the substrate will be, and therefor the better the holding. Between a concave and convex shape, might the convex shape while being set and shedding material, be able to dig deeper? Could that be an advantage?
caltexflanc
Guru
While I have not had the intestinal fortitude to read every post in this thread, a few overall themes emerge to me (when I say "boat" I mean the boat and its ground tackle system) :
• Most of the participants don't anchor out very much, so anchoring is still some sort of voodoo rite to them. Or, they only anchor in one kind of bottom. Or, both.
• People do not observe how their boat actually interacts with the water and weather, as evidenced by those who do not understand how current shifts work on their boat, or how the wind shifts direction and affects their boat.
• The lack of distinguishing between an anchor grabbing and an anchor setting. The universal desire to plop the anchor into the water and just have it grab with no further work.
In my opinion, the above issues cause the over, and, again in my opinion, ultimately virtually useless, analysis of the design of that hunk of metal at the very end of the boat, a phenomena the anchor marketers exploit to their advantage, several thousand years after man began anchoring water craft.
• Most of the participants don't anchor out very much, so anchoring is still some sort of voodoo rite to them. Or, they only anchor in one kind of bottom. Or, both.
• People do not observe how their boat actually interacts with the water and weather, as evidenced by those who do not understand how current shifts work on their boat, or how the wind shifts direction and affects their boat.
• The lack of distinguishing between an anchor grabbing and an anchor setting. The universal desire to plop the anchor into the water and just have it grab with no further work.
In my opinion, the above issues cause the over, and, again in my opinion, ultimately virtually useless, analysis of the design of that hunk of metal at the very end of the boat, a phenomena the anchor marketers exploit to their advantage, several thousand years after man began anchoring water craft.
Bigsalmonfish
Senior Member
Post 555 is right on!
Quote by Great Laker:
Originally Posted by Marin http://www.trawlerforum.com/forums/...g-power-test-15941-post271530.html#post271530
The issue of convex vs. concave is purely physics or geometry or whatever science it is. A concave survace concentrates material--- be it mud, air, or dirt in a ditch-- by forcing it toward the center of the suface. In the case of an anchor, a concave fluke surface will concentrate the bottom material toward the center of the fluke, which will increase the fluke's resistance to the direction of pull. It's why the concave surface of a shovel picks up and holds more dirt than the convex side.
A convex surface sheds material.
One thing occurs to me that I have not heard considered, but I may have missed it here or in a different thread.
It seems reasonable that the deeper the anchor gets, the more compact the substrate will be, and therefor the better the holding. Between a concave and convex shape, might the convex shape while being set and shedding material, be able to dig deeper? Could that be an advantage?
Rex Wrote:
Well it has worked a treat for us over twenty two years, remember convex without directional outward sheers is not a plow, deeper penetration favors the Excel over the Super Sarca as it has no roll bar, then again the Super Sarca has a greater holding area so depth is not so crucial.
Regards.
Rex.
Originally Posted by Marin http://www.trawlerforum.com/forums/...g-power-test-15941-post271530.html#post271530
The issue of convex vs. concave is purely physics or geometry or whatever science it is. A concave survace concentrates material--- be it mud, air, or dirt in a ditch-- by forcing it toward the center of the suface. In the case of an anchor, a concave fluke surface will concentrate the bottom material toward the center of the fluke, which will increase the fluke's resistance to the direction of pull. It's why the concave surface of a shovel picks up and holds more dirt than the convex side.
A convex surface sheds material.
One thing occurs to me that I have not heard considered, but I may have missed it here or in a different thread.
It seems reasonable that the deeper the anchor gets, the more compact the substrate will be, and therefor the better the holding. Between a concave and convex shape, might the convex shape while being set and shedding material, be able to dig deeper? Could that be an advantage?
Rex Wrote:
Well it has worked a treat for us over twenty two years, remember convex without directional outward sheers is not a plow, deeper penetration favors the Excel over the Super Sarca as it has no roll bar, then again the Super Sarca has a greater holding area so depth is not so crucial.
Regards.
Rex.
Delfin
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Yes.
HopCar
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Rex, I wish I was in a position to be your US distributor. I think your anchors would sell.
I think it would be a no brainer for Imtra Corporation. They already import Muir Windlasses from Oz, have the warehouse facilities and are already established as a distributor in the USA.
I think it would be a no brainer for Imtra Corporation. They already import Muir Windlasses from Oz, have the warehouse facilities and are already established as a distributor in the USA.
Yes hopCAR you are right they do sell well over their, thanks very much for the contact I will look into it in the furture as we supply Muirs for over seas customers such as Imtra.
You are a good bunch blokes on the TF, thanks for your concern and contact.
Regards Rex.
You are a good bunch blokes on the TF, thanks for your concern and contact.
Regards Rex.
BruceK
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Considering the lamentable Aussie costs of production and shipping distances I`m amazed Muir markets competitively in USA, they have trouble doing it here. But they are quality,they provide back up service, and within reason, quality & reliability can beat price. My Muir Cheetah (with its new 1200w motor) and my Super Sarca get along fine.
Nomad Willy
Guru
While we were talk'in Rocnas and alloy the Susan Gael got some very traditional steel anchors mounted in her nostrils.
The Claw looks like a Bruce to me and the Danforth is a bit interesting in the way it's put together. And the pads have a steeper angle than most.
But the Skipper seems unmoved by high tech. He could be using the Danforth as primary and the Bruce when it's rocky. Or he could be using the Bruce as primary and the Danforth when it blows. ??
The Claw looks like a Bruce to me and the Danforth is a bit interesting in the way it's put together. And the pads have a steeper angle than most.
But the Skipper seems unmoved by high tech. He could be using the Danforth as primary and the Bruce when it's rocky. Or he could be using the Bruce as primary and the Danforth when it blows. ??
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Ranger42...I think you've got it, when you said..
"I wonder if a concave design eventually collects enough weight toward the back of the fluke such that the tip no longer points downward..... so the direction of pull becomes more or less horizontal from that point on?
Whereas a convex surface maybe never collects enough weight toward the back so that the tip always still points downward... and the direction of pull continues to dig deeper?"
Exactly. The so-called streamlined shape of the convex fluke, which in essence is not a plough shape, but more like one side/half of an arrow head split longitudinally, parts the substrate, and the net vector forces are such as to drive it deeper, something only really possible because of the material shedding shape. Concavity would just result in it filling up, then at that point, max holding power and depth is largely reached, (quite considerable, I might add), but if it's holding power is exceeded, all it can do is pop out, or hopefully perform a controlled drag digging a deep trough in the sea bottom. The convex fluke can continue to go down deeper, and if it then dragged, it is a controlled drag, with the substrate filling in over and behind it. Only when being pulled vertically, as in retrieval, will it then shed the material more easily than concave, and come up cleaner.
The above is my personal experience with a Super Sarca.
"I wonder if a concave design eventually collects enough weight toward the back of the fluke such that the tip no longer points downward..... so the direction of pull becomes more or less horizontal from that point on?
Whereas a convex surface maybe never collects enough weight toward the back so that the tip always still points downward... and the direction of pull continues to dig deeper?"
Exactly. The so-called streamlined shape of the convex fluke, which in essence is not a plough shape, but more like one side/half of an arrow head split longitudinally, parts the substrate, and the net vector forces are such as to drive it deeper, something only really possible because of the material shedding shape. Concavity would just result in it filling up, then at that point, max holding power and depth is largely reached, (quite considerable, I might add), but if it's holding power is exceeded, all it can do is pop out, or hopefully perform a controlled drag digging a deep trough in the sea bottom. The convex fluke can continue to go down deeper, and if it then dragged, it is a controlled drag, with the substrate filling in over and behind it. Only when being pulled vertically, as in retrieval, will it then shed the material more easily than concave, and come up cleaner.
The above is my personal experience with a Super Sarca.
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Anchor Brian
Senior Member
Just posted on boats.com. Author Gary Reich also writes for PassageMaker and his story should be in their next issue as well
Anchor Throw-Down: Fortress Anchor Tests 11 Popular Hooks - Articles - boats.com
Anchor Throw-Down: Fortress Anchor Tests 11 Popular Hooks - Articles - boats.com
Nomad Willy
Guru
Peter B,
Sounds like you're over think'in this concave/convex (CC)issue on a defensive level I suspect.
The CC question is simply a question of what shape resists fwd motion through a fluid. Didn't the Spade designer research this thoroughly and establish it as fact that the concave shape was best? Correct me if I'm wrong but I consider that a given.
It was also considered a given that a heavier anchor works better but the Fortress and even the Danforth designed in 1938 shows that there are other elements of a design of anchors that trump weight.
The concave fluke has greater resistance as the Rocna and Supreme may show but given the choice I'd take the Super Sarca for an anchor as it's setting and short scope performance is better not to mention it's apparent greater seabed flexibility.
Re your analysis of the CC issue since the concave resists fwd motion better (that is largely vertical re an anchor) it would seem the concave would be more resistant to rising up in the seabed and that should result in deeper penetration. But as I've said there's more to anchor design than optimizing fluke efficiency. The Frenchman's Spade fluke looks to be optimized for efficiency but there are quite a few anchors that can out perform the Spade.
Sounds like you're over think'in this concave/convex (CC)issue on a defensive level I suspect.
The CC question is simply a question of what shape resists fwd motion through a fluid. Didn't the Spade designer research this thoroughly and establish it as fact that the concave shape was best? Correct me if I'm wrong but I consider that a given.
It was also considered a given that a heavier anchor works better but the Fortress and even the Danforth designed in 1938 shows that there are other elements of a design of anchors that trump weight.
The concave fluke has greater resistance as the Rocna and Supreme may show but given the choice I'd take the Super Sarca for an anchor as it's setting and short scope performance is better not to mention it's apparent greater seabed flexibility.
Re your analysis of the CC issue since the concave resists fwd motion better (that is largely vertical re an anchor) it would seem the concave would be more resistant to rising up in the seabed and that should result in deeper penetration. But as I've said there's more to anchor design than optimizing fluke efficiency. The Frenchman's Spade fluke looks to be optimized for efficiency but there are quite a few anchors that can out perform the Spade.
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Nomad Willy
Guru
Ranger42C wrote;
"Without regard to cleanliness...
I wonder if a concave design eventually collects enough weight toward the back of the fluke such that the tip no longer points downward... so the direction of pull becomes more or less horizontal from that point on?
Whereas a convex surface maybe never collects enough weight toward the back so that the tip always still points downward... and the direction of pull continues to dig deeper?
Not arguing, simply thinking (typing) out loud, as it were."
Interesting theory.
Seems to me the fluke would collect material (weight) aft ... the amount being about equal to the area of the fluke. Since the area of most flukes is smaller toward the tip (forward) there should be less buildup. But I think the anchor designer must locate the shank on the anchor in a balanced way to control pitch attitude.
During the initial set the tip receives more weight and helps pitch down. But as the anchor moves fwd and down material becomes more balanced as planned by the anchor designer. Interestingly the Rocna has a short up-turn to the trailing edge of the fluke like an aircraft elevator. This would presumably concentrate the collection of material in the aft end of the fluke tending to pitch the anchor up. And also to aid in the compaction or interplane drag theory. I think it's possible this could contribute (or be the cause) of the poor short scope performance. The Supreme has no such feature and has Supreme short scope performance. Couldn't resist the pun.
But when fully buried the down force on the fluke should be balanced re where the area of the fluke is distributed fore and aft.
Another thing that occurs to me re material concentrated aft on the fluke is that before the anchor is buried but when the fluke is fully engaged is that the material at and on top of the trailing edge of the fluke can pile up above the seabed surface. The material on top of the tip cannot because the seabed material on top of it holds it down as it dosn't have anywhere to go. So as a result of unbalanced fluke loading the anchor would likely pitch down. This temporary un-balance may be of great benefit to many anchors.
"Without regard to cleanliness...
I wonder if a concave design eventually collects enough weight toward the back of the fluke such that the tip no longer points downward... so the direction of pull becomes more or less horizontal from that point on?
Whereas a convex surface maybe never collects enough weight toward the back so that the tip always still points downward... and the direction of pull continues to dig deeper?
Not arguing, simply thinking (typing) out loud, as it were."
Interesting theory.
Seems to me the fluke would collect material (weight) aft ... the amount being about equal to the area of the fluke. Since the area of most flukes is smaller toward the tip (forward) there should be less buildup. But I think the anchor designer must locate the shank on the anchor in a balanced way to control pitch attitude.
During the initial set the tip receives more weight and helps pitch down. But as the anchor moves fwd and down material becomes more balanced as planned by the anchor designer. Interestingly the Rocna has a short up-turn to the trailing edge of the fluke like an aircraft elevator. This would presumably concentrate the collection of material in the aft end of the fluke tending to pitch the anchor up. And also to aid in the compaction or interplane drag theory. I think it's possible this could contribute (or be the cause) of the poor short scope performance. The Supreme has no such feature and has Supreme short scope performance. Couldn't resist the pun.
But when fully buried the down force on the fluke should be balanced re where the area of the fluke is distributed fore and aft.
Another thing that occurs to me re material concentrated aft on the fluke is that before the anchor is buried but when the fluke is fully engaged is that the material at and on top of the trailing edge of the fluke can pile up above the seabed surface. The material on top of the tip cannot because the seabed material on top of it holds it down as it dosn't have anywhere to go. So as a result of unbalanced fluke loading the anchor would likely pitch down. This temporary un-balance may be of great benefit to many anchors.
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eyschulman
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I have said it before and now reconfirm after reading the Throw-Down test, An advertising stunt. Certainly the people at Fortress, who specified the very narrow test nature, knew before the test that Danforth anchors ,especially with 45 degree fluke sets, would stand out in soft mud and that many other brands would do poorly. If this were meant to be an anchor test of any significance it would need to include multiple bottom types and variations relative to real world anchoring. Practical Sailor Magazine has been preforming ongoing anchor testing for years. The results of those tests do not show the Fortress in a bad light, but do point out that there are other New-Gen anchors that do well as all around performers. My best guess is that the recent growing trend in anchor purchases moving toward New-Gen spade types has alarmed the people at Fortress and any close look at boating magazines regarding what's on the bows of boats will confirm that trend. Look at what's on my bow. It is not perfect but it has so far shown itself to be an all around good performer even in soft mud.
The rollbar doesn't contribute to setting, it contributes to the fluke penetrating into the bottom so the anchor can then set.
The principle and operation of the rollboar anchor are so obvious and so simple that even a caveman could understand it. But I'm beginning to see that a surprisingly large number of participants on this thread apparently don't, in fact, understand it despite their claims that they do.
The videos I have seen showing rollbar anchors digging in out of sight into the bottom would tend to contradict the armchair theoriies being thrown around here that the rollbar prevents the anchor from really digging in.
But videos can't be believed, right?
Every time we use our rollbar anchor we have to break it out with the boat. And when it comes up, the hollow rollbar is always packed tight with bottom material, so much so I have to blast it out with a hose when we get home.
This would indicate that the rollbar was taken a fair distance into the bottom if not all the way into it.
Reality trumps theory every time. Rather than armchair theories like those being bandied about in this thread about how an anchor will behave based on how it looks, we sought out experiences related by boaters who had been using a particular type of anchor in real-life situations all over the planet. There were a fair number of them even back then, although it took a bit of effort to search them out.
For example: Eric-- have you changed your fleet of charter boats in the Mediterranean from the conventional anchors they were equipped with to rollbar anchors and had the anchoring problems your customers experienced go from a lot to almost none?
No?
I didn't think so. But the largest charter operator in the Med did, and this was many years ago when rollbar anchors were fairly new to the market.
Sure, there are instances of rollbar anchor users experiencing dragging or other problems. That's to be expected, given the almost infinite number of variables in the anchoring process.
But the armchair theories and assumptions that have filled this thread--- not just about rollbar anchors but all different types--- are really something to read. Entertaining? Certainly. Credible? Absolutely not.
In addition to our own experience, we stake the security of our boat at anchor on the real-life experiences of boaters who have actully used the type of anchor we have for a long, long time in a whole lot of situations. If a bunch of these people had been experiencing the kinds of problems that have been theorized and conjectured about in this thread, we never would have bought the anchor.
But guess what? Nobody was.
There are people participating in this thread who I suspect are, for whatever reason, really pissed off at the success of the rollbar anchor. And there are people who, I am becoming convinced, simply don't know how it works despite their claims otherwise.
But none of them appear to have had years of real-life experience with this anchor. I don't mean dragging one around on a 2:1 scope or theorizing how this or that little bend in the metal will react with the mud the anchor is oozing through at a snail's pace. I mean using one for years-- don't forget, these things have been around in one form or another for a long time now--- in actual boating conditions: different bottoms, different winds, different currents, etc.
Those are the folks worth paying attention to. The rest of it's just fluff.
PS-- While I wrote the above with regards to the rollbar anchor, it also applies to any anchor the armchair crowd is theorizing about, be it the Fortress (another great anchor), Rex's anchor, or any other. Reality trumps theory every time.
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Nomad Willy
Guru
Marin this is an armchair discussion so I'm not concerned about being "credible" but I'm glad I've scored at the entertainment level. I was just hoping someone was reading my home baked ideas.
What is it about the roll bar that you don't think we understand? But I think I understand it better than you and of course you think I don't understand it and I'm a sub-cave man. That's a bit of a low blow but what can I do about it? I just had my hair cut .. fairly short too.
It seems Rocna's new anchor isn't a roll bar. Looks more like a Spade than anything else. I wonder why they dumped the RB?
What is it about the roll bar that you don't think we understand? But I think I understand it better than you and of course you think I don't understand it and I'm a sub-cave man. That's a bit of a low blow but what can I do about it? I just had my hair cut .. fairly short too.
It seems Rocna's new anchor isn't a roll bar. Looks more like a Spade than anything else. I wonder why they dumped the RB?
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Anchor Brian
Senior Member
I appreciate your input, but no, we are not alarmed. For a large part of our business, we are not competing for the same customers, as they have virtually no penetration into the small boat market, nor will they ever due to their pricing.
Additionally, we have a niche product with features and benefits they simply cannot offer.
Old generation anchors such as the Bruce (or Claw), CQR, Danforth and copies (particularly in overseas markets) still have a huge market share advantage, and the new generation models are all competing for a very small slice of the pie.
Lewmar, manufacturers of the Claw, CQR, and Delta, probably sell more anchors than all of the new generation anchor manufacturers combined in the USA and world market. Maybe even 2-3x. Lewmar certainly has vastly superior distribution.
Regarding the soft mud testing, I guess you have to identify what constitutes being a "good performer." If you are referring to the Ultra, it did have a couple of good spikes during the testing of over 1,000 lbs, but then it broke free immediately afterwards and never reset.
All of its pulls ended at less than 900 lbs (what is needed to hold a 35-ft boat in 30 knots of wind per ABYC table) and 4 of 5 pulls ended at less than 600 lbs.
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