Mantus Anchors .... shank strength

SolentSnowgoose

SolentSnowgoose

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I know that starting another thread about anchors is risky but ......

I have been looking at retiring the old CQR in favour of one of the newer types and the Mantus made in the US and sold in Holland seems interesting based on cost and reported / claimed performance.

The only concern is a reference by Practical Sailor magazine in the US that the shank looks a bit thinner than other brands

Can anyone throw any light on this...?

Thanks
 
I was considering one of these and Neeves (one of our resident anchor gurus) posted the following:

Neeves said:
.....
I would steer very clear of the Mantus, its shank has less than half the strength of the current Delta, Rocna and maybe one third the strength of a Supreme and Excel (I approximate). It is also steel, thus heavy. There was talk of an upgrade of the shank - but if this has happened it has been kept very quiet. It also has a rather voluminous, and essential, roll bar making it something that will fill a locker - all by itself.
.....
Jonathan
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I followed up on your comments and contacted Mantus direct.

Greg Kutsen of Mantus confirmed that they will be changing the material specification to ASTM 514 in a couple of weeks.

This seems to put the Mantus on an even footing with the others who are using higher spec steel in the shank.

The whole topic of anchors seems to engender some strong opinions and sometimes its hard to see who is independent and who is not

I also think its possible that the comments in the US Practical sailor actually originated from the same person who is quoted in the previous post.
 
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SolentSnowgoose said:
I also think its possible that the comments in the US Practical sailor actually originated from the same person who is quoted in the previous post.
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That is the case. I did not post in this thread yesterday as I thought Neeves might reply overnight, but he must be elsewhere. I can assure you that he is totally independent and impartial when it comes to anchor testing. He has carried out a great deal of research into anchor strengths and related topics, mostly reported in Practical Sailor.
 
Sorry I was up the coast for 36 hours and did not access the internet - It has been boisterous here and I was busy:)

I can confirm that Mantus have publicly stated they are changing (have changed) the shank material from the original A36 (mild steel, around 300 MPa) to A 514, which is an 800 MPA steel. Mantus have also stated they will change any mild steel shanks, without question, when the new shanks are available. The change in steel specification will increase strength by around 2.6 times (a direct reflection on use of better steel). A514 is the same steel quality used by Manson in its Supreme, Anchor Right in its Excel and the original steel spec for Rocna. The Rocna, when last reported, now uses a slightly lower grade steel (700 MPa) and its shank strength, similar in dimension to the Supreme and Excel of similar weight, is around 90% of their strength.

The Mantus shank is made from the same steel thickness plate as the similar weight Supreme, Rocna and Excel, so thickness is not an issue. However the Mantus shank width is around 65% of the width (width, looked from the side) of the equivalent weight Rocna, Supreme or Excel and will thus have approximately 65% of the strength of the Supreme and Excel and around 75% strength of the Rocna (please excuse my rounding of data).

The Rocna and Excel shanks seem based largely on the Delta shank which has a strength near that of these 2 anchors - I'm not too sure as I cannot be precise about the steel used in the Delta shank - but independent comment suggests something similar to that of the Rocna and Excel. The Manson shank is slightly different, in fact has a bit 'more' steel.

The off spec Rocna's that CMP (or their distributors) changed whenever requested and were the subject of the West Marine specification notice were made from a steel of around 500 MPa (and sometimes lower). Since Rocna changed to the 700 MPa steel there have been no recorded instances of bent shanks (and one that turned up recently in the Med was probably one of the older 'off spec' models). There have been no recorded instances of bent Supreme or Excel shanks - noting this is not data that manufacturers publicise, but there is no forum exposure (though the Excel usage is limited largely to Oz and NZ).

The comment in PS of questionable shank strength of the Mantus does seem vindicated as Mantus are upgrading by a factor of 2.6 times. It is a pity it took Mantus so long to effect the change but commendable they will change all the mild steel shanks - if requested. I would be unable to agree, given 'less width' of the Mantus shank that it is on an even footing as those other anchor makers using higher specification steels.

It is possible to make an anchor from mild steel with a strong shank - the shank just needs more steel (though thick shanks detract from hold). It is equally possible to use a high tensile steel and the shank be not very strong (if its too thin or lacks width).

If you think and find shank strength to be not of significance you will find the Mantus a good anchor. I see no reason to compromise on ground tackle and am prepared to pay the price demanded for a shank that might be 'over engineered'.

The Mantus sets as well as its peers, has good hold. It has a very large fluke, so if tested should have a more than adequate holding capacity. I do not think yacht owners will be able to differentiate the speed of setting nor hold between Rocna, Excel, Supreme and Mantus, despite their manufacturers claims. There are other differences - but that is not an issue in this thread. The rather voluminous roll bar has been designed to try to reduce any issues of carrying/lifting 'seabed' - but does mean it might not fit on some bows, nor in some lockers. It is demountable - though I'm not sure this is a great attribute in a primary anchor. The galvanisng of the, mild steel, Mantus models I have look good - but hi tensile steels are notoriously difficult to galvanise (to the same levels as mild steel).

There are concerns over 'hydrogen embrittlement' of hi tensile steels, specifically A 514 (or Bisplate 80 as used in Oz and the material originally used by Rocna and still used by Manson and Anchor Right). Despite these concerns and fears there is not one instance of HE in any anchor that has been publicised or aired on an internet forum and the original Rocnas have now been in use for around 10 years and Supreme and Excel for not much less.

I hope this clarifies the position.

Good Luck,

Jonathan
 
To the op. I know this was not your concern but the fact that the Mantus is demountable would put me off using it as our main anchor. I think I would be constantly checking that the bolts were nipped up and maybe sometimes lie awake wondering if I had remembered to check before deploying the anchor. The bolts may be able to be moused which would solve the issue but I have not seen the anchor so do not know.

Just my feeling and would probably not put many off.
 
The bolts are galvanised Grade 5 (Class 5?) hi tensile bolts. They are supplied with beefy, gal, spring washers. I have been assured, emphatically, that they are strong enough and even though I am sure the manufacturers are right I wish the 4 bolts for retaining the shank had been stronger - it surely would not cost? I also wish the bolts had not been load bearing in the first place - a shank coming up through a slot in the fluke looks an option.

But I'm not an anchor maker (obviously - or I would not make such stupid comment!)

I think if you took it apart frequently the gal of the nuts, washers and bolts would wear off, quite quickly, so maybe one would need to replace them.

But dismantled it would take up little room, the fluke is almost flat, the shank flat and the roll bar could tuck away quite easily.

Jonathan
 
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There are bolted connections all over your boat, predominantly on the engine, that undergoes considerable thermal fluctuations and vigorous vibration. None of these come undone of their own accord, so why should the four that connect the anchor shank to the fluke? Provided you torque them up correctly there is no reason why they should take it into their heads to unscrew.

Despite that, I would have thought a design in which the shank flange was below the fluke rather than above it would overcome any fears of owners, but no doubt they had their reasons.
 
The bolts are parsimonious in length, there is enough room for the nut and washer but not enough to drill a reasonable hole. The best you could do would be drill through nut and shank when its all tightened up and put a pin through, but the hole will not have gal on it. If you are not going to disassemble you could use Loctite or simply burr over the tops of the shanks (but you'll knock the gal off! I'm with Vyv, they do seem pretty secure, I would not worry about them coming apart if correctly tightened.

Few anchors actually bend in use when at anchor. They do bend in sudden storms but its not that common. Most anchors seem to bend on retrieval, over enthusiastic lifting with the engine in forward and a well set anchor, a short scope (as you are lifting); impact load generated by waves; getting caught under a rock is an obvious example. High holding anchors are much more prone, if they have a weak shank, than an old fashioned low holding design (because the older designs break out more easily) But if a shank does bend when you are half way through a 14 day cruise on the west coast of Scotland it would really upset your holiday! You could of course buy a spare shank initially (which is an option for other anchors that disassemble).

How attractive is the pricing in the UK, compared with Rocna and Supreme? They are very attractively priced in America. Some/most/all of the saving of making in China seem to be passed onto the customer. That attractiveness can disappear very quickly if they ship from America and add on, what seems to be, a common distributor margin.

Jonathan
 
I cannot find any UK distributors other than Mantus themselves who sell online and heaven knows what the carriage would be on a one off. I may be wrong but nothing shows up on Google in the first few pages.

The problem with anchors is that everyone knows best. For example, I would never rely on an anchor with nuts and bolts, I want one piece of solid metal. Some people hate the hoop on the Rocna/Manson but I like it because it makes taking it off the bow roller easier (forgetting it's functionality on the seabed). There is also the emotional attachment. Once you have chosen an anchor and it has looked after you in a blow, you convince yourself it was the right decision to have bought it. I am genuinely attached to my Rocna (NZ) for these reasons.

I was being flippant with my comment about you and Vyv but was half serious .....
 
Storyline said:
The problem with anchors is that everyone knows best. For example, I would never rely on an anchor with nuts and bolts, I want one piece of solid metal. Some people hate the hoop on the Rocna/Manson but I like it because it makes taking it off the bow roller easier (forgetting it's functionality on the seabed). There is also the emotional attachment. Once you have chosen an anchor and it has looked after you in a blow, you convince yourself it was the right decision to have bought it. I am genuinely attached to my Rocna (NZ) for these reasons.

I was being flippant with my comment about you and Vyv but was half serious .....
Click to expand...


I thought the OP said there was a Dutch distributor?


I think you are correct about the emotional attachment of owners to their anchor and that attachment colouring ones views. That emotional attachment is also a characteristic of anchor makers - there is a total inability to see good in someone elses design and see possible weakness in ones own design (with definite emphasis on the latter). Given we have 3 basic concepts of concave, convex and fluke - there is a foundation to ensure forum threads will continue for ever. I've noticed a fear about initiating anchor threads - I think people should not feel in any way threatened (we are always going to be learning). Its a bit like a discussion on multi vs mono - but I'm not suggesting going there! But in many respects its healthy - I'd hate to think we, the consumer, not having a choice and as long as the anchor makers are passionate that choice will remain. We, the public, need to be a bit cautious and make sure corners are not cut - and so far there are have been (interesting corporate choices but) no disasters.

My standard view on anchors is 'they are a compromise'. Whereas I have a favourite we try to carry at least 3 totally different concepts (each of which is 'big enough' to be a primary) when we go 'away' - as opposed to day trips.

I'm not quite sure why you want to take your anchor off the bow roller - but I have seen comment on YBW that the place to store an anchor is in the anchor locker - but I want my anchor on the bow roller so that it can be deployed immediately (or at my easy convenience). Its never 'held' by the windlass on passage - but we never take it off.

Jonathan
 
There have and are so many claims by manufacturers, and a larger number of claims and opinions expressed by boaters that I have been mulling over a protocol for an anchor test that would contain information I would think desirable to know. If anyone has input on this design, I would very much appreciate hearing about it.

The protocol would be based on tests done on one size of anchor in one bottom type - essentially a shallow shoreline test with the motive pull force provided by a 5 ton winch from onshore. The reason for selecting a single size and sea bed is because this test would recognize that different weights and different conditions might yield different results, but that a baseline performance of a single set of conditions would still be useful for comparing designs. I would imagine a 15 kg size would be most useful for most boaters.

The testing would include a number of tests:

1. From a position where the anchor is on its back, what is the distance traveled before the anchor tip digs in 3 inches?
2. From a position where the anchor is properly positioned for digging in, what is the distance traveled before the anchor tip digs in 3 inches?
3. What is the maximum resistance provided, and what is the distance traveled before that maximum resistance is achieved? (I'd probably set 5,000# as an arbitrary maximum pull)
4. At maximum resistance, what is the depth the anchor achieves, measured from seabed surface to the tip of the fluke?
5. With the fluke immobilized, what is the deflection of the shank with a sideload 50# of force? (This would be repeated in 50# increments until deformation occured)
6. With the fluke immobilized, what is the sideload where 1" of permanent distortion is induced?

The seabed I have in mind is saturated sand/shell, which we have in abundance in the NW.

The anchors I would test would be all 3rd generation types, including an Excel, an Ultra, a Mantus, a Kobra, a Rocna, a Delta, a Fortress (not 3rd gen, but a good benchmark), and a Manson. I have omitted the Spade as I believe the Ultra would exhibit similar characteristics, but maybe I need to include one of those as well. This ensemble would include three convex (Delta, Excel and Kobra), one flat (Fortres), 2 concave (Manson and Rocna), and one combination convex and concave (Ultra).

The purpose would be, at least for this size and seabed, to resolve a few areas of dispute on anchor threads. These would include:

1. Concave anchors hold better than other types. (probably false)
2. Convex anchors, because of a weighted and thicker tip, don't dig in as well as thinner concave hoop anchors. (probably false)
3. Shank strength doesn't matter. (it might not, but users should at least know the relative strengths of different designs.

The problem, of course, is that I would be destroying in the shank bending test a bunch of anchors, but setting cost aside, does this protocol sound useful to the experts here?
 
Hi Delfin,

Great concept, all that's needed is the support of the anchor makers to supply some anchors.

You have not defined what you are going to use as the rode nor what scope ratio you will work to.

I'd prefer a chain rode, as that is what most of us use and I'd suggest 8mm or maybe 5/16th inch. You could use cable for most of the rode - its only the length that is to be attached to the anchor that needs to be chain. Simple standard shackle. I think most of set at short scope, say, 3:1 and then adjust depending on the conditions to 5:1, 7:1. etc - so I might be inclined to set at 3:1 but move to say 7:1 once you want to define the maximum holding capacity. This means you need some sort of rig to allow setting at that scope ratio - and ensuring it is the same for every anchor.

Diving depth is an interesting measure, not usually done (I did some tests about 6 months ago - but for different reasons). This could be achieved 2 ways. Measure depth at a nominal load, say something representing what one might expect, say around 1,000lb, for a yacht using that sort of anchor (though 1,000lb is high) and maybe secondly at increments of 500lb. Some anchors might 'bottom out' - it would be interesting to find out 'when' (or where) though the bottoming out ought to be where maximum load is achieved. From experience in testing 15kg to 2,000kg you spend most of your time digging anchors out rather than actually testing them! Lots of labourers are useful (I'd invite the media - they would enjoy the exercise). When I measured diving depth I used a thin cord attached to an eye on the anchor, I simply pulled the cord tight, so that it was vertical, and then measured the length. I also measured the length of chain that was 'buried.

I'd certainly include a Spade (except for the cost of destroying a Spade:( (and Ultra:(). They have different shank construction and it would be invaluable to compare and compare with simple plate shanks. I'd also include an alloy Excel, if Anchor Right have it right the shank should be stronger than their Bis shank. Boss?

Total support for your side load shank strength test. Normal 'large' loads are snatch loads but simulating them are difficult (I cannot think of a safe way to do it).

I'm not keen on your 'one seabed' concept (but accept if that's what you have its the cheapest way to go) as, with my 'anchors are a compromise' philosophy some anchors work better in 'other' seabeds and identifying the strengths and weaknesses before destroying them all sounds - economic(?).

Expensive - but also setting the same, or some of them, anchors from a vessel could show that the beach testing is 'realistic' and then gives credibility to the whole test programme.

When you send me my airticket I'll collect any 'antipodean' anchors you have not be sent by the manufacturers and bring them in my hand luggage.

See you soon:)

Jonathan
 
Delfin said:
does this protocol sound useful
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Distance to set and depth of set would be useful. Like Jonathan I would prefer to see a range of seabeds tested even if it meant reducing the parameters you are measuring. The seabed you are suggesting sounds like a very easy substrate for anchors and it may prove difficult to get meaningful separation between the various designs.

Hard sand really separates the men from the boys with poor designs just not setting.
It would be great to see some results in weed. It is difficult to find a uniform seabed of weed, but this is a common substrate for people to have problems so it would be nice to see someone try.

If possible I would include the steel Spade it is benchmark anchor. I still think we have not settled the question if it better or worse than the a Rocna/MS (probably because they are very close). The Boss would be a great inclusion as there has been very little data.
 
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Neeves said:
.....
I'm not quite sure why you want to take your anchor off the bow roller - but I have seen comment on YBW that the place to store an anchor is in the anchor locker - but I want my anchor on the bow roller so that it can be deployed immediately (or at my easy convenience). Its never 'held' by the windlass on passage - but we never take it off.

Jonathan
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I designed and had built a custom made twin bow roller for Storyline. The stb side has a self launching flappy bit and port is for moorings. It works really well for overnight stays on moorings but when we leave the boat on our permanent mooring I remove the anchor in case it gets involved with the mooring chain when we are not there. As soon as wet set off, we put the Rocna on its roller and I was lucky with the measurements as it locks off securely when on passage. Like you, it is always ready for action should we need it in a hurry.

I did not read the original post properly because I missed the reference to the Dutch distributor. They need to improve their SEO because as I said they do not show up on the first few pages on Google. The majority of the results point to various threads on yachting forums ! If I were them i would allocate some cash for an AdSense campaign in the UK, although I suppose if you really wanted one Mantus themselves would direct you to their distributor.

Commercially, I think there is an opportunity for a new gen kedge anchor. I posted on a thread a while back about the Mantus as we need a new kedge. I liked the idea of a demountable new gen type design but you pointed out the suspect shank and Vyv extolled the virtues of the Fortress. I then did quite a bit of research reading on all the main global yachting forums and everything I read pointed to the Fortress. It appears to be the de facto anchor of choice for a kedge. This is a very different situation to the market for bower anchors where, as we all know, there are many competing designs that all work well. It seems to me that all boats need a kedge so the market should, in theory be nearly as big as that of bower anchors. As I said before, a demountable new gen design would be an attractive option and would only have one serious competitor.
 
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noelex said:
Distance to set and depth of set would be useful. Like Jonathan I would prefer to see a range of seabeds tested even if it meant reducing the parameters you are measuring. The seabed you are suggesting sounds like a very easy substrate for anchors and it may prove difficult to get meaningful separation between the various designs.

Hard sand really separates the men from the boys with poor designs just not setting.
It would be great to see some results in weed. It is difficult to find a uniform seabed of weed, but this is a common substrate for people to have problems so it would be nice to see someone try.

If possible I would include the steel Spade it is benchmark anchor. I still think we have not settled the question if it better or worse than the a Rocna/MS (probably because they are very close). The Boss would be a great inclusion as there has been very little data.
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I would like to see a test showing which anchor performed best in a muddy bottom. I do not know how common mud is in cruising grounds around the world but in Scotland it is very common. The experience I have had with the Rocna shows it is fail-proof in sand, always setting very fast. However mud is a different story. This is where some art comes in when trying to get the anchor to set properly. It has proved easy to pull the Rocna out if one goes about the process with too much gusto. Some anchorages are heavily used and the mud must become silty and they are even more of a challenge. I have had many years of experience in these places using a 35lb CQR and my gut feeling is that it pefomred as well if not better than the Rocna when it came to setting. I cannot comment on ultimate holding because we are lucky in that neither of the anchors have ever dragged.

I realise that one of the main purposes of Noelex's tests would be to quantify anchor strength but for us, a test in mud would be interesting. Then there is kelp, another sod to anchor in. Our technique there dates back to a comment made in jest by a guy we sail with regularly. I will have a first and second attempt the traditional way, lay out cable to a generous scope then slowly pull back. If this fails after two attempts we use Jeff's 'chuck it all over' method. This involves dumping 30m of chain or so in one spot and then motoring briskly in reverse. The crazy theory is that the chain should cut through the kelp (not very environmentally friendly). Perversely and without logic, this sometimes works.

I suppose one test cannot suit everyone and I can see the advantage of using sand as it would be easier to replicate the same conditions for each anchor.

Good luck with the tests Delfin. I hope you get the support of the anchor makers.
 
To me a kedge needs to be light as you might need it when you run aground and then you will need to deploy by dinghy - and a steel kedge of anything over about 20kg would be a nightmare (to deploy under control). This means the kedge needs to be alloy - which size for size seem to work out about half the weight of their steel equivalents. The most popular would be the Fortress which is well established (but there is also the alloy Spade - which is simply so expensive). Our 10 year old granddaughter can deploy the Fortress - which puts it into context.

But a Mantus as a kedge looks like a non-starter simply because its steel - unless you have a small yacht.

But my ideas are overlaid by the concept that I see little point in carrying a 'small' kedge. If I'm carrying multiple anchors I do not see the value in a small anchor that can only be used as a kedge when I can carry a full sized (same effective holding capacity as the primary) but half the weight if its alloy and use the alloy as a kedge (if needed) or back up (or replace) the primary - if its needed. A Mantus, could fill this need in our case (as we only use a 15kg primary) but carrying a 8kg Fortress is ideal and is so much easier than trying to deploy a 15kg steel anchor from a dinghy in the dark and rain (so the demountable attributes of the Mantus become redundant).

Alloy has bad vibes - people think it weak and shy away, forgetting (or ignoring) that Fortress have survived for 20/25 years and you do not do that. especially in America, if your product is not built to meet the physical demands imposed upon it.

I think everyone who goes away for the more than a weekend cruise should think of an alloy anchor but it should be assembled ready for use - when you need it you might need it in a hurry! So again the demountable aspect is a bit wasted on us! Fortunately a Fortress is flat, or flattish, and stores well in a locker (though you do need quite a big locker).

But not to show too much favour - we also carry an alloy Spade, which is equally as versatile as the Fortress (and same weight). We tried the original alloy Excel (which we rather badly bent) but the new model looks the business and, as I mentioned, might be stronger than their Bis 80 steel version. We have yet to try it in anger but initial trials are excellent.



We installed an extra bow roller on the cross beam of our cat to allow us to 'take' mooring buoys (but on our home mooring we use a bridle to horn cleats on each bow). If we deploy 2 anchors (and we use our Fortress) we would use one off the horn cleats as our second anchor is a mixed rode and we would simply secure the nylon off one bow.

Jonathan


Apologies to the OP if the thread seems to have been hi-jacked - but its an unusual anchor thread, largely non-controversial. Maybe we should have more:)

Jonathan
 
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