Mantus vs Rocna

The only difference I can see between the Mantus and Rocna, using the MK1 eyeball, is that a Mantus is a Rocna that can be stored in a suitcase. So I would expect them to perform equally, unless the fluke area of a Mantus is larger because it’s a lighter construction for a given weight. The fact that the Mantus was cheaper would make it a winner in any magazine test
 
You, in common with most, missed the critical point - they are very, very different and this difference make them perform completely differently.

Yes they look the same, or similar.

Now look underneath at the sole of the fluke.

Rocna is ballasted with a double plate thickness in the toe. The Mantus has no ballast - yet they 'look' the same.

This means that the centre of gravity of the anchors are different (completely different) and this impacts how they perform in the seabed and results in the Mantus fluke angle in a sand seabed being about 16 degrees but the Rocna, with its ballast, has a fluke seabed angle of 30 degrees. This results in the Rocna, for the same weight, having about twice the hold of the Mantus.

Yours is a common mistake - read the article I posted earlier. But you are amongst many - many have made the same assumption. Of course because Mantus has not been exhaustively tested and the results published (by Mantus - for one) who would know.

However the fluke/seabed angle is the giveaway - if you measure the fluke seabed angle for a Spade, Excel, Rocna, Danforth they are all at around 30 degrees (it does vary). Mantus is the only anchor illustrating a consistent fluke seabed angle of 16 degrees. All the research (and testing of Mantus) equates similarly sized flukes at 30 or 16 degrees to have hold of 50% less for the 16 degrees.

Looks are deceptive - unless you check the differences - and that ballast is critical.

Now - its easy to modify - but you compromise strength. There are unballasted fluke anchors - which have the hold of a Rocna etc - they provide the answer.

If Noelex had not posted hundreds maybe thousands of images all neatly collected together I confess I might have missed the conclusion (though when I originally tested the Mantus I had the answer, but took some time to sink in - Noelex provided the confirmation that my anchor was normal, to Mantus). But you would think someone who spent years taking those photos and is a self proclaimed anchor expert that he would have realised.

I have asked Noelex to show me I, the US Navy, HM Navy, Vryhof etc, am wrong - I am still waiting - but I think he is in denial. But then I have been waiting for month for him to justify his idea that a larger anchor is safe at short scope. I note he is very quick to be critical of Fortress tests (and others), for example, but he is quite happy to make claims he cannot verify himself.

Whether the manufacturer knew, I doubt - but they know now and are keeping very, very quiet. They are not disputing my assertions by testing (with independent witnesses) - just silence.

If any magazine tested exhaustively they would identify immediately (as is seen in Fortress Chesapeake tests). But why would magazine test - these are tests any responsible and professional anchor maker should complete before they put their product to market.

Mantus has the hold of a similar weighted Delta. Mantus sets reliably - so, yes, it is better than a Delta. But a Spade, Rocna, Excel sets quickly and reliably and have about 2 times the hold, for similar weight.

I wrote that last sentence with care - Mantus does not set quickly - it takes a long time to set to the same hold as say a Rocna - this is what a Mantus owner here said

'The Mantus sets in about 3m reverse, digs into any soft substrate and resets easily'.

Most of the new anchor set in a shank length, call it about 1m. The distance is a reflection of trajectory at 16 degree and trajectory at 30 degrees - simple stuff.


Now - why do I worry, do I have a grudge against Noelex or Mantus - not a bit. But I DO dislike spruiking without understanding, I do dislike the idea that people are being misled, I do dislike the idea of making extravagant and dangerous claims with no basis. People have bought a Mantus on the basis of Noelex - they say so on his thread.

There is a rather ominous question mark regarding Mantus - why have they not tested their anchor exhaustively against Spade, Rocna and Supreme etc. Sadly this same question mark is raised over some of their other products (some since amended) - like the testing off their first anchor hook, why market the anchor originally with a mild steel shank (you must have lived under a stone not to have heard of the Rocna debacle) and why knowing new replacement HT shanks had been shipped would you continue to sell/ship anchors with mild steel shanks. Cavalier comes to mind.

It easy to fool people (but as you mentioned - having spent a tidy sum on your Rocna you would not want to be shown you have bought a lemon (not suggesting you did, hopefully your eyes were open) - replace your Rocna with their Mantus - how might they feel. Denial come to mind.

or

it much more difficult to convince them they have been fooled.

Jonathan
 
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noelex said:
As promised below is the link to the Kippari test which tested the holding power of the Mantus and the Rocna anchor. I would encourage reading the report rather than relying on my summary. You can use Google/Bing translate, although I would suggest the references to the penis in some translated versions may not accurately reflect the authors intent :)

There are also some nice side photos of the fluke/shank angle of different anchors on page 40.

Unfortunately, these modern tests do not have the budget that was available for the earlier large scale studies so they do have some limitations. Nevertheless, this is an independent study that looks at the holding power of both the Mantus and Rocna anchor so I think it worth reading, together with Fortress test if you are interested in the performance of these two anchors (although I would further caution that the Fortress test has been paid for, conducted and analysed by an anchor manufacturer).

http://www.uchimata.fr/wp-content/uploads/2015/03/Essais-comparatif-Mantus-03-2015.pdf
Click to expand...

You have mentioned this twice - that Fortress made the analysis - this is incorrect and insulting.

Fortress invited a cross section of the yachting press to sit in on the tests. Fortress would be unable to influence what was written (in the same way the yachting press was invited to the West Marine tests in 2006). I think Fortress link to each of the reports. The analysis that Fortress relied on was provided by Robert Taylor possibly America's leading anchor expert who spent most of his career working for the US Navy. To suggest he was biased is an insult to his integrity. Fortress was obviously showing that their product was superior in their selected seabed - but that would not influence how the other anchors performed. They had an axe to grind, or an anchor to sell, but would not worry how Mantus performed.

Mantus performed exactly as would be predicted for an unballasted fluke anchor, like Danforth or Fortress whose fluke/seabed angles were 30 degrees, 32 degrees and 45 degrees vs that of Mantus at 16 degrees. Do the maths - its about 2nd year high school level, or read the article I linked. As the tests show - ballasted anchors did not perform well - but we are comparing unballasted anchors, like with like.

Jonathan
 
And finally

The much vaunted Kippari result where Mantus shines

The research into fluke seabed angles is not confined to the impact of fluke angle on hold in a sand seabed. Part of the research, or another part of the research, shows the importance of a wider angle in thin soupy mud, clearly demonstrated if one compares a Fortress set at 32 degrees and one set at 45 degrees in their Chesapeake tests.

Really the Fortress set at 32 degrees is pretty average but when set at 45 degrees hold improves in soupy bottoms. None of this is unknown and on the Mekong the big river barges have their Danforth types set, permanently, at about 40 degrees. The phenomena is also know by the oil rig anchor companies who have anchors where the shank/seabed angle can be manipulated by alter the shank/fluke geometry.

It is also known (and its simple extrapolation) that in very hard seabeds a low fluke/seabed angle is advantageous, as is a sharp toe. In fact there are a couple of papers produced by Robert Taylor where he has a spread sheets defining remedies for certain seabeds and for a hard seabed he recommends a low seabed/fluke angle and a sharp toe (visions of sailors with files sharpening the toe of aircraft carrier anchors :) ).

Now 2 of the characteristics of Mantus is:

Low seabed/fluke angle

Sharp toe

The characteristic of quarry floors is

Hard Bottom.

In fact in private conversation in an unguarded moment the owner of Mantus, the company, has declared the anchor was actually designed and focussed at hard seabeds - and I recall he did have some beach tests that showed this to good effect. But I have not heard, or tucked away for future reference, of seabeds where a Rocna, Excel, Spade or Supreme have been defeated because the eabed was too hard - so the anchor, Mantus, appears to have been designed for an illusory anchorage (maybe a quarry floor :) ).

So Noelex - next time you anchor in a quarry - you have the perfect anchor - but most of us are not going to be quite as adventurous and simply want the best hold in sand (and maybe mud) where a Rocna, Spade, Excel or Supreme will, for the same weight, have twice the hold as a Mantus.

But don't worry your Mantus has about the same level of hold as a 50kg Delta - and it is well perfectly sized for your yacht

Jonathan
 
Just to keep the fires burning....... :devilish:

Does it make that much difference any more if anchor X has a tiny bit more hold than anchor Y in a one off test somewhere, for experienced cruisers anyway.
Must have been so different a few decades ago with those awful CQRs & everyone thinking the catinary or a chum would make all the difference when the wind really piped up.
The amount of more scientific info these days about the benefits of a really good snubber system coupled with many excellent modern anchor designs must have revolutionized staying put for so many. Add to that the availability of up to date accurate weather forecasts and we're so much more likely to get a good nights sleep. :cool:

Just anchor on the windward side so the charter numpties don't drag into you :)
 
GHA said:
Just to keep the fires burning....... :devilish:

Does it make that much difference any more if anchor X has a tiny bit more hold than anchor Y in a one off test somewhere, for experienced cruisers anyway.
Must have been so different a few decades ago with those awful CQRs & everyone thinking the catinary or a chum would make all the difference when the wind really piped up.
The amount of more scientific info these days about the benefits of a really good snubber system coupled with many excellent modern anchor designs must have revolutionized staying put for so many. Add to that the availability of up to date accurate weather forecasts and we're so much more likely to get a good nights sleep. :cool:

Just anchor on the windward side so the charter numpties don't drag into you :)
Click to expand...

Exactly so. My own view is that ultimate holding power in all modern anchors is so high that it makes no difference - my snubber is weaker than the anchor hold and there is no sign of it breaking.

I am far more interested in the ability of the anchor to reset when the wind shifts. I have numerous underwater photos showing that my Rocna turns on the fluke without any linear movement, which seems to me to be the ideal result. I have seen Manson Supreme do exactly the same but have no experience of others. Although having previously used a Delta for 20 years, much of that in tidal waters, I never dragged on the turn with that either.
 
vyv_cox said:
I have numerous underwater photos showing that my Rocna turns on the fluke without any linear movement, which seems to me to be the ideal result.
Click to expand...
Yes, consistency is vital for a bit of confidence, think the most resets in one spot was something like 300 and not once did the transit of the palm tree behind the little shack bar change. And being able to cope with a wide range of bottoms, there's a fortress onboard for a kedge & really soupy bottoms but never needed yet, maybe in the Chesapeake, not that that's likely ;)
 
GHA - I agree. Most of the new designs have similar hold. A 15kg Rocna, Supreme, Spade and Excel have holds in a decent sand seabed of around 2t - no yacht (sized for a 15kg anchor) is ever going to experience a 2t tension in their rode. One can argue model X has more hold than Y but as you are never going to experience that tension - so what? The older designs, also 15kg, had a hold in the same seabeds of around 1t - and people still swear by them (and if they are well set they hold - or the people who swear by them would stop swearing :) )

The difference is that the new designs seem more forgiving and easier to achieve that reliable hold.

There are obviously other differences - but holding capacity is something that can be measured (or so the Claification Societies and many magazines believe). The Morgan's Cloud recommendation is a more subjective issue and there are other issues.

But which would you rather have - a 15kg anchor that holds 1t or one that holds 2t? If you were to buy a modern anchor - what would you expect, a hold similar to Rocna or a hold similar to Delta. To be more focussed would you rather have on a, nominal, 40' yacht a 20kg Rocna or a 40kg Mantus (both offering the same hold). If you want more hold - then you need buy the 25kg Rocna or the 50kg Mantus.

To me holding capacity is a good place to start - we have plenty of choice and a design to suit every whim - Rocna, Supreme, Knox, Excel, Spade - my question is - why would you buy an anchor with half the hold?

Jonathan
 
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vyv_cox said:
I am far more interested in the ability of the anchor to reset when the wind shifts. I have numerous underwater photos showing that my Rocna turns on the fluke without any linear movement, which seems to me to be the ideal result.
Click to expand...
This is a very important property.

I miss the lack of recent large independent anchor holding tests, but they ignored (or largely ignored) this aspect of anchor performance.

Fortunately, observing anchors underwater is a great way to study their response to a change in the direction of pull. The best anchors stay almost level with their flukes buried and engaged with the seabed throughout the rotation. As Vyv mentioned, the anchor does not move other than rotate.

Anchor designs that are poor at rotating develop a high list. Their fluke loses much of its grip during the rotation. In most cases even anchors that are poor at rotating will regain their grip and rebury once the new direction of pull is established. The owner will be unaware that anything untoward has occurred. However, this type of rotation is much less secure. An anchor rotating in this manner is vulnerable to a gust at the wrong time, when the grip is low during the high list phase. The gust can cause the anchor to move while it has this low grip, and once moving an anchor has a much harder time digging back into the substrate.

This needs to be observed on actual anchors. Simulations, at least of 180° windshifts, invariably result in the anchor breaking out completely or sometimes even flipping over. I suspect this may be because the anchor has not had time to consolidate the substrate, but it may be that the chain movement is not simulated correctly without a real wind or current shift. In actual use, anchors that are good at rotating very, very rarely break out even with repeated 180° windshifts, providing the substrate is reasonable and the anchor is set. Marks in the substrate show how the anchor has rotated, even after the event, and I have never seen either my Rocna or Mantus breakout or do anything other than “shuffle”.

To get back to the original thread question, both the Rocna and Mantus rotate extremely well. This is one of the features that attracts me to these anchors. The Mantus has a very slight edge. It stays a little more level (probably because the “wings” provide a very large width to the base of the fluke) during rotation, but the improvement is not enormous.

If you get a chance to observe your anchor rotating it is fascinating to watch. The only warning is that if you have a model that rotates poorly you will never sleep through a windshift again :). The difference between anchors that are good, and those that are bad at rotating is very pronounced so you do not need to see many different examples to draw conclusions.
 
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The 2006 YM/West/Sail anchor tests did do some resetting tests in different bottoms but the results were not particularly well presented and were overwhelmed by the far more obvious total hold measurements. Could be worth revisiting the article although my recollection is that nothing stood out as being great in one seabed but not in another. Fortress came out best in all categories but it transpired that it was not comparable with all the 15 kg/35 lb steel ones, disproportionately huge as I recall.
 
Maybe all these anchor threads have a lot in common with willy waving:- it's not so much what you have, more what you do with it. :D
 
I think that the most important attribute for an anchor is fast and reliable setting in difficult seabeds. If they can achieve that there is not a lot more to be said. Who cares how well their anchor sets in a perfect seabed. Those arent the conditions that cause us problems. When the seabed is a mixture of sand and dead coral and setting is difficult, then give me an anchor with weight over the sharp tip so it can dig in fast and not drag more than the length of the anchor. Give me an anchor that holds with 3:1 scope because have you seen how crowded anchorages get these days! This is reality for lots of cruisers.
 
Not used a Mantus anchor, the only ‘new Generation’ anchors I have used are the Spade and the Rocna.

Briefly, neither has given any concerns at all but the Rocna bites harder so let’s you know it’s well set in no uncertain terms - but seems to pick up more weed. I ‘think’ it digs in deeper as it’s harder to break out than the Spade was or maybe I’m more confident in hanging off the hook in breezy places...
 
wully1 said:
Not used a Mantus anchor, the only ‘new Generation’ anchors I have used are the Spade and the Rocna.

Briefly, neither has given any concerns at all but the Rocna bites harder so let’s you know it’s well set in no uncertain terms - but seems to pick up more weed. I ‘think’ it digs in deeper as it’s harder to break out than the Spade was or maybe I’m more confident in hanging off the hook in breezy places...
Click to expand...

Thats the beauty of anchor threads. My experience is the opposite. The Rocna never gave me confidence so we went back to a Spade. Even with our very large and powerful windlass its amazing how far the bow dips when breaking out our Spade
 
noelex said:
This is a very important property.

I miss the lack of recent large independent anchor holding tests, but they ignored (or largely ignored) this aspect of anchor performance.

Fortunately, observing anchors underwater is a great way to study their response to a change in the direction of pull. The best anchors stay almost level with their flukes buried and engaged with the seabed throughout the rotation. As Vyv mentioned, the anchor does not move other than rotate.

Anchor designs that are poor at rotating develop a high list. Their fluke loses much of its grip during the rotation. In most cases even anchors that are poor at rotating will regain their grip and rebury once the new direction of pull is established. The owner will be unaware that anything untoward has occurred. However, this type of rotation is much less secure. An anchor rotating in this manner is vulnerable to a gust at the wrong time, when the grip is low during the high list phase. The gust can cause the anchor to move while it has this low grip, and once moving an anchor has a much harder time digging back into the substrate.

This needs to be observed on actual anchors. Simulations, at least of 180° windshifts, invariably result in the anchor breaking out completely or sometimes even flipping over. I suspect this may be because the anchor has not had time to consolidate the substrate, but it may be that the chain movement is not simulated correctly without a real wind or current shift. In actual use, anchors that are good at rotating very, very rarely break out even with repeated 180° windshifts, providing the substrate is reasonable and the anchor is set. Marks in the substrate show how the anchor has rotated, even after the event, and I have never seen either my Rocna or Mantus breakout or do anything other than “shuffle”.

To get back to the original thread question, both the Rocna and Mantus rotate extremely well. This is one of the features that attracts me to these anchors. The Mantus has a very slight edge. It stays a little more level (probably because the “wings” provide a very large width to the base of the fluke) during rotation, but the improvement is not enormous.

If you get a chance to observe your anchor rotating it is fascinating to watch. The only warning is that if you have a model that rotates poorly you will never sleep through a windshift again :). The difference between anchors that are good, and those that are bad at rotating is very pronounced so you do not need to see many different examples to draw conclusions.
Click to expand...

Given your total inability to identify that your anchor, uniquely, has a seabed/fluke angle of 16 degree (or your total inability to point out the same) and your total inability to justify many of your outlandish claims - your credibility looks about zero.

How can you expect anyone to take your comments seriously when you claim a large anchor is safe at short cope, but cannot justify the statement, when you claim to examine and study anchors underwater and completely miss (or omit to mention a primary and negative characteristic) - and when challenged you simply ignore the challenge.

You criticise other anchors, you criticise anchor tests (but recommend people to read a test conducted in an old quarry without any water, hide behind anonymity but make dangerous and outlandish statements you cannot support and thus taken no responsibility for much of what you post. The danger is, and confirmed, people believe your rubbish and act on it.

The unacceptable face of internet forum at its worst.

Jonathan
 
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geem said:
Thats the beauty of anchor threads. My experience is the opposite. The Rocna never gave me confidence so we went back to a Spade. Even with our very large and powerful windlass its amazing how far the bow dips when breaking out our Spade
Click to expand...

And I couldn't tell the difference between the 2, both behaved impeccably all over the place in many different bottoms :)

Actually I suspect that the rocna might bite in a bit quicker but that's so subjective it's not worth thinking it's anything more than unreliable.
 
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