Mantus Anchor or Rocna ?

[Mantus 1]

Hello All,
Mantus Anchors also will be at the Seattle Boat Show! We will be in the East Hall booth 1128. Please stop by and see all our products that we have and ask us about them!
Greg, Dean, and Thomas

[VanIslandGuy]

Didn't see Mantus at the Vancouver show but Rocna and Sarca both had good booths.

[groundtackle]

Just sold the big #13 63kg Excel in the photo to a Fleming 55 owner. He's pretty happy about it!

[pcmm]

Originally Posted by Mantus 1

Hello All,
Mantus Anchors also will be at the Seattle Boat Show! We will be in the East Hall booth 1128. Please stop by and see all our products that we have and ask us about them!
Greg, Dean, and Thomas

Will you be at the largest indoor boatshow in North America? the Toronto Boat show?

[Mantus 1]

PCMM we will not be there this year. Put the plan is to be next year.

[malbert73]

Anyone chuckle through the latest PS issue? That author is so biased against mantus for unknown reason that this is last straw for me when my subscription runs out. if anyone knows what a Rocna supreme is please let me know. And how does the author conclude the Rocna has a better setting angle than mantus based on this picture with the shanks clearly not aligned?

http://www.cruisersforum.com/forums/....php?p=2320724




Sent from my iPhone using Cruisers Sailing Forum

[thinwater]

Originally Posted by malbert73

Anyone chuckle through the latest PS issue? That author is so biased against mantus for unknown reason that this is last straw for me when my subscription runs out. if anyone knows what a Rocna supreme is please let me know. And how does the author conclude the Rocna has a better setting angle than mantus based on this picture with the shanks clearly not aligned?

Cruisers & Sailing Forums - View Single Post - Mantus

Attachment 140836


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Before you get to bellicose, try this experiment. Take the scoop anchor of you choice (Manson is easy because it has a rock slot) and vary the angle of the blade a few degrees by moving the attachment point. In fact, simply moving the rode from the single hole to the front of the rock slot changes the angle by several degrees. Then set the anchor in the bottom. What you will see is that for every 1 degree change in angle of the fluke, the angle the fluke finally takes in the bottom changes by about 2.5 degrees. As I recall, the article referenced a thread in this forum where you can see this for your self. The angles in the picture probably do approximate the angle the anchor takes in the bottom when just buried. But that is not the whole story.

Next, consider what this does to holding capacity and setting ease. For example, Fortress sets well in sand at 32 degrees and not at all at 45 degrees. But Fortress is much more powerful in mud at 45 degrees.

We also know that Mantus did very well in the resent Solomons Island tests, perhaps best among NG anchors, depending upon how you read the data. This seems odd for a low angle anchor, but excellent setting and other design features added up to a solid performance. Rocna, with "better angles," flubbed.

What does this tell us? Probably that there will never be one best answer. A wood chisel will never look like a cold chisel, the materials they are designed to cut are just too different. The other thing I have learned from testing is that there are a lot of great anchors out there. I have a Manson Supreme, But I would be willing to trade for any number of NG anchors. I doubt I could tell the difference (I've pull-tested quite a few).

[toddedger]

If I remember correctly the Rocha guy originally took his design to Manson. Manson said no and then came out with their Supreme design shortly after. That's where the nasty war started.

The one thing the Rocna has going for it over the others is they are the only one to add the extra hole for tandem anchoring. Now for tandem anchoring they recommend using a simular sized anchor for the second anchor. The only simular anchor I have room to carry is the Mantus because it can be disassembled. MANTUS or ROCNA ? I say one of each

[DumnMad]

Originally Posted by thinwater

Before you get to bellicose, try this experiment. Take the scoop anchor of you choice (Manson is easy because it has a rock slot) and vary the angle of the blade a few degrees by moving the attachment point. In fact, simply moving the rode from the single hole to the front of the rock slot changes the angle by several degrees. Then set the anchor in the bottom. What you will see is that for every 1 degree change in angle of the fluke, the angle the fluke finally takes in the bottom changes by about 2.5 degrees. As I recall, the article referenced a thread in this forum where you can see this for your self. The angles in the picture probably do approximate the angle the anchor takes in the bottom when just buried. But that is not the whole story.

Next, consider what this does to holding capacity and setting ease. For example, Fortress sets well in sand at 32 degrees and not at all at 45 degrees. But Fortress is much more powerful in mud at 45 degrees.

We also know that Mantus did very well in the resent Solomons Island tests, perhaps best among NG anchors, depending upon how you read the data. This seems odd for a low angle anchor, but excellent setting and other design features added up to a solid performance. Rocna, with "better angles," flubbed.

What does this tell us? Probably that there will never be one best answer. A wood chisel will never look like a cold chisel, the materials they are designed to cut are just too different. The other thing I have learned from testing is that there are a lot of great anchors out there. I have a Manson Supreme, But I would be willing to trade for any number of NG anchors. I doubt I could tell the difference (I've pull-tested quite a few).

This is just too sensible and correct to be on an anchor thread.

[malbert73]

Originally Posted by thinwater

Before you get to bellicose, try this experiment. Take the scoop anchor of you choice (Manson is easy because it has a rock slot) and vary the angle of the blade a few degrees by moving the attachment point. In fact, simply moving the rode from the single hole to the front of the rock slot changes the angle by several degrees. Then set the anchor in the bottom. What you will see is that for every 1 degree change in angle of the fluke, the angle the fluke finally takes in the bottom changes by about 2.5 degrees. As I recall, the article referenced a thread in this forum where you can see this for your self. The angles in the picture probably do approximate the angle the anchor takes in the bottom when just buried. But that is not the whole story.

Next, consider what this does to holding capacity and setting ease. For example, Fortress sets well in sand at 32 degrees and not at all at 45 degrees. But Fortress is much more powerful in mud at 45 degrees.

We also know that Mantus did very well in the resent Solomons Island tests, perhaps best among NG anchors, depending upon how you read the data. This seems odd for a low angle anchor, but excellent setting and other design features added up to a solid performance. Rocna, with "better angles," flubbed.

What does this tell us? Probably that there will never be one best answer. A wood chisel will never look like a cold chisel, the materials they are designed to cut are just too different. The other thing I have learned from testing is that there are a lot of great anchors out there. I have a Manson Supreme, But I would be willing to trade for any number of NG anchors. I doubt I could tell the difference (I've pull-tested quite a few).

I get what you are describing in concept. But in reality when I swapped my rocna for a mantus the angle between fluke and shank looked nearly identical sitting next to each other on the dock. The picture in PS has the shanks oriented completely differently, so I really don't see how they (you?)reached your conclusions. I like the idea of considering these concepts but to my eye there seems to be a underlying PS attempt to discredit the mantus which has great real world performance. (As a analogy- I'm a doctor and when pharma "literature" tries to sell me on intermediate data like cholesterol numbers, I usually reject that data in favor of objective outcomes data, like reduction in heart attack, stroke, and death. )

Also, what is a "rocna supreme"- is the anchor in the picture a manson?

[a64pilot]

Mantus, Rocna

Isn't it a little Ford or Chevrolet? Yes one will have better this, the other better that, but in the end very close.
I'd go with whoever would give me the best customer service, and that is likely Mantus?
Says the guy with two Rocna's on the bow

[evm1024]

Originally Posted by malbert73

Anyone chuckle through the latest PS issue? That author is so biased against mantus for unknown reason that this is last straw for me when my subscription runs out. if anyone knows what a Rocna supreme is please let me know. And how does the author conclude the Rocna has a better setting angle than mantus based on this picture with the shanks clearly not aligned?

Cruisers & Sailing Forums - View Single Post - Mantus

Attachment 140836


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That would be Jonathan Neeves who goes by jonjo on this board if I recall correctly. You can ask him about it....

[thinwater]

Originally Posted by malbert73

I get what you are describing in concept. But in reality when I swapped my rocna for a mantus the angle between fluke and shank looked nearly identical sitting next to each other on the dock. The picture in PS has the shanks oriented completely differently, so I really don't see how they (you?)reached your conclusions. I like the idea of considering these concepts but to my eye there seems to be a underlying PS attempt to discredit the mantus which has great real world performance. (As a analogy- I'm a doctor and when pharma "literature" tries to sell me on intermediate data like cholesterol numbers, I usually reject that data in favor of objective outcomes data, like reduction in heart attack, stroke, and death. )

Also, what is a "rocna supreme"- is the anchor in the picture a manson?

Re-read the article. Set both anchors in sand to equivalent strain and the angles will be different. They will be, probably similar to what was presented. That does NOT, by itself, mean the holding capacity is different. But that is the angle the article described, not the angle on the driveway. Photos in the bottom would have greatly reduced confusion.

After reading the article I took 2 anchors (Manson Supreme and Mantus) and played with them, adjusting the fluke angle just a few degrees by moving the rode attachment point 1-2 inches. The difference in behavior and holding capacity was quite significant, though I prefer not to publish the results here. Run your own experiments. It also made it clear just how sensitive anchors are to manufacturing tolerance. Did moving the attachment point (changing the angles) make either of the anchors better or worse? No, it made them different. Better or worse depends on what is most important to you and the nature of the bottom.

The article was not intended to reach a conclusion and does not. It points out that anchors with different angles are likely to have different performance characteristics, just as the Fortress anchor changes when the angle changes. Which is better depends on what you need, so Fortress provided both. Personally, I find it hard to believe there can be one best answer, just as a bread knife and a hacksaw are different.

Rocna Supreme is obviously a typo. Big whoop.

[evm1024]

Just for fun I went to the mantus and rocna sites and downloaded their templates for the 45# and 20 kg anchors and printed them out. Then I cut them out and assembled them.

Placing the cutouts over each other I was hard pressed to visually see the difference in angles.

Projecting the fluke plane and shank plane back I measured 20.8 degrees for the Mantus and 17.4 degrees for the Rocna. Of course there is a a bit of slop in my taping the pages together but it appears that the difference in angles is around 3.4 degrees.

Is this enough to cause a significant difference? Who knows. I would venture that the other geometries of the anchors likely swamp a 3.4 degree difference. This is clearly obvious e.g. is the center of resistance nearer to the tip of the fluke or nearer to the tail? Plus as the rode lifts off the sea bed the angle of the pull changes in relation to the plane of the fluke. So many variables.

Here is a photo from my phone. The Rocna template faces the other direction from the Mantus and is thus upside down. This photo is to just illistrate what was done.

[malbert73]

Great post there. That's the issue with even raising the question of angle. What matters more is real world setting. Videos by panope and pictures by noelex and others are far more valuable than an article debating this and raising questions that are not borne out in real world conditions. If mantus really sets at a shallower angle than rocna in real world, then how in the world did it hold much better in soft mud on chesapeake than rocna (and manson if I remember right)? To me it means that the setting angle isn't worth debating.

And if it sounds like I have a stake in this, I guess I do. Bought a mantus years ago for my prior boat, based on great boat show interaction with their folks. Loved it. Couldn't believe setting ability. Then neeves and PS started raising theoretical shank issue (despite that many anchors like danforth and fortress have slender shanks for generations) so when I bought my current boat, I decided to get a rocna. Decidedly different experience than mantus- several drags on wind shifts, several times it didn't set. Finally sold it and got a mantus. Amazingly better on all counts. So I was initially swayed away from a superior anchor due to someone's writing who seemed intent on questioning mantus. If someone reads latest PS, they may come to erroneous conclusion despite a mere passing reference to how much better mantus fared in their real world testing earlier.