It's True! The Mantus 65-lb. hooks first time, everytime.

[Delfin]

Originally Posted by Mantus Anchors

After, being attacked I realized that there is no real data on the subject of shank strengths and that people writing on the subject bring incomplete and often inaccurate information to the end consumer... and induce unnecessary panic in the eye of the consumer....

Not quite sure you were attacked. Observations were made that the steel you say you use currently produces a shank that exhibits fractional strength given its physical dimensions when compared to alternative steel. You apparently agree, because you are changing your steel without ever acknowledging that your current product needs the significant improvement the move to A514 would represent, or explaining why, if the change really isn't needed you are making it at all.

You've presented calculations on the strength of the Fortress that don't match actual physical testing, calling into question the reliability of your methodology or assumptions. Noting this gap between your calcs and reality isn't an attack, but another question of why the gap exists.

Others have questioned whether your assertion that your anchor is fine without the roll bar could be true, since the anchor is perfectly stable inverted without the roll bar. But again, if the anchor is fine without the bar, why bother to include it?

Some have chosen to view asking these questions as an attack, displaying a partisan preference which you must deserve on some basis. Whatever that basis, it doesn't appear to be forthright answering of legitimate questions put to you in a straightforward way. But the questions remain, and remain unanswered. If noting that constitutes an attack, I guess maybe you have been attacked.

[Cotemar]

This thread was started by windswepttom (The OP=original post) who had a great experience with his new Mantus anchor.

This thread has now turned to an AR team against Mantus Anchors.

No one has ever reported a bent shank to Mantus, but the AR team feels it there duty to take down any anchor competition.

Mantus Anchors currently use mild steel shanks and are transitioning over to high strength ASTM A514 (780 MPa steel yield strength) alloy shanks. They have never had a claim for a bent shank and have a Lifetime Guarantee. http://www.cruisersforum.com/forums/f102/its-true-the-mantus-65-lb-hooks-first-time-everytime-110154-6.html#post1368769

For those who do not know ASTM A514 (Mantus new shank material) is equivalent to Bisplate 80 (AR excel shank material).

For anyone following this anchor conundrum, this may clarify the AR team.
JonJo = writes anchor reviews giving AR anchors top ratings and support
Congo = CEO of AR Australia
Factor = has and AR excel anchor and defends them like no other
Delfin = does not have an AR excel anchor, but thinks they are the best
Downunder = has and AR excel anchor and defends them like no other

This AR team keeps repeating their questions on this thread and then another one will come in and re-affirm what they feel should be the answer.

To the OP that started this thread, sorry that the AR team has taken charge of your thread and turned it from a good experience into a bad one. They had done this on a few anchor threads last year also, so you’re not alone.

[Delancey]

Originally Posted by Cotemar

This thread was started by windswepttom (The OP=original post) who had a great experience with his new Mantus anchor.

This thread has now turned to an AR team against Mantus Anchors.

No one has ever reported a bent shank to Mantus, but the AR team feels it there duty to take down any anchor competition.

Mantus Anchors currently use mild steel shanks and are transitioning over to high strength ASTM A514 (780 MPa steel yield strength) alloy shanks. They have never had a claim for a bent shank and have a Lifetime Guarantee. http://www.cruisersforum.com/forums/f102/its-true-the-mantus-65-lb-hooks-first-time-everytime-110154-6.html#post1368769

For those who do not know ASTM A514 (Mantus new shank material) is equivalent to Bisplate 80 (AR excel shank material).

For anyone following this anchor conundrum, this may clarify the AR team.
JonJo = writes anchor reviews giving AR anchors top ratings and support
Congo = CEO of AR Australia
Factor = has and AR excel anchor and defends them like no other
Delfin = does not have an AR excel anchor, but thinks they are the best
Downunder = has and AR excel anchor and defends them like no other

This AR team keeps repeating their questions on this thread and then another one will come in and re-affirm what they feel should be the answer.

To the OP that started this thread, sorry that the AR team has taken charge of your thread and turned it from a good experience into a bad one. They had done this on a few anchor threads last year also, so you’re not alone.

I think it worth a mention that JonJo, a self described "Independent Maritime Professional and Marine Journalist" with a degree in Geology and Terrestrial Surveying is not an engineer. He has nothing to lose and everything to gain by creating controversy and positioning himself as an authority thereby increasing his perceived value and marketability as journalist.

[avb3]

I just ran across this article which discusses what Amazon CEO Bezos considers why some companies are liked and others not. As soon as I read it, I had to think of the actions of some within this thread. Here's the link and I am posting some of the poignant points in the article for consideration by members.

http://www.businessinsider.com/jeff-...panies-2013-10

Rudeness is not cool.
Defeating tiny guys is not cool.
Close-following is not cool.
Young is cool.
Risk taking is cool.
Winning is cool.
Polite is cool.
Defeating bigger, unsympathetic guys is cool.
Inventing is cool.
Explorers are cool.
Conquerors are not cool.
Obsessing over competitors is not cool.
Empowering others is cool.
Capturing all the value only for the company is not cool.
Leadership is cool.
Conviction is cool.
Straightforwardness is cool.
Pandering to the crowd is not cool.
Hypocrisy is not cool.
Authenticity is cool.
Thinking big is cool.
The unexpected is cool.
Missionaries are cool.
Mercenaries are not cool.

[conachair]

Originally Posted by avb3

Rudeness is not cool

[JonJo]

I promised my self I would not post until my previous post had been answered.

It is agreed that bending forces on a lever are calculated from a multiplication of width x thichness (squared) x Yield Stress all divided by length. The resultant figure is then multiplied by a constant dependent on whether you are dealing in newtons, kilios or lbs (and also whether you are mixing metres and mm etc.

Mantus introduced a detailed description of the Fortress shank and I am aware that my skills at 3D modelling are non-existent but I am sure the analysis is perfect. As pointed out I am educated as a geologist and surveyor (neither of which I practised professionally). (And I am not a professional yachtsmen either). What is surprising is the effort made to analyse a competitors product but nothing on their own product.

However the apparent indication that the Fortress shank might be weak does merit a response.

If you look at the data in my previous post you will find that the Fortress and Mantus shanks are surprisingly similar and they are ostensibly for similar sized yachts.

They are both about 650mm long (Fortress is longer which would make it say 10% weaker) but it is also wider and these 2 differences effectively cancel out. They both use materials of the same Yield Stress, Fortress' is higher, based on minimums by about 10% - but not much in it. The killer is that the Fortress shank is 2 times as thick as the Mantus and as it is the square of thickness (to determine resistance to bending) this means that the Fortress is about 4 times as strong.

Possibly comparing a straight beam to a geometric shape (the Delta shank) is unfair but casting aspersions about a competitor is also unfair (when your own characteristics remain 'hidden') - but personally I'm not sure in this case that the differences in geometry are that significant.

The Fortress might, in Mantus eyes, not cut the mustard but the Mantus shank has 25% of its strength.

I appreciate that many do not like the idea I have maintained a focus on one specific product but my previous post underlines the reason. I think that if the shank is based on the steel grade quoted then it has not been manufactured to the strength that might be expected. I was also concerned about the 'remove the roll bar' video. If it is not safe for the roll bar to be removed for 100% of the people 100% of the time then some cautionary note should be produced - it has not happened. I had hoped that the facts would be looked at, addressed swiftly and quietly, and that it would all go away. That has not happened - hence my persistence. If you like the idea of anchors with shanks able to withstand 100kg for 35' yachts then I understand you will think I am a nuisance. If you think airing a video that might not be 100% safe is acceptable - then you will not like my persistence.

I thank you for your patience and tolerance and humbly apologise as I have obviously upset some of you.

I'll leave the thread pending Mantus quantification and explanation of the video.

With warm regards,

Jonathan

[Delancey]

Originally Posted by JonJo

I promised my self I would not post until my previous post had been answered.

It is agreed that bending forces on a lever are calculated from a multiplication of width x thichness (squared) x Yield Stress all divided by length. The resultant figure is then multiplied by a constant dependent on whether you are dealing in newtons, kilios or lbs (and also whether you are mixing metres and mm etc.

Mantus introduced a detailed description of the Fortress shank and I am aware that my skills at 3D modelling are non-existent but I am sure the analysis is perfect. As pointed out I am educated as a geologist and surveyor (neither of which I practised professionally). (And I am not a professional yachtsmen either). What is surprising is the effort made to analyse a competitors product but nothing on their own product.

However the apparent indication that the Fortress shank might be weak does merit a response.

If you look at the data in my previous post you will find that the Fortress and Mantus shanks are surprisingly similar and they are ostensibly for similar sized yachts.

They are both about 650mm long (Fortress is longer which would make it say 10% weaker) but it is also wider and these 2 differences effectively cancel out. They both use materials of the same Yield Stress, Fortress' is higher, based on minimums by about 10% - but not much in it. The killer is that the Fortress shank is 2 times as thick as the Mantus and as it is the square of thickness (to determine resistance to bending) this means that the Fortress is about 4 times as strong.

Possibly comparing a straight beam to a geometric shape (the Delta shank) is unfair but casting aspersions about a competitor is also unfair (when your own characteristics remain 'hidden') - but personally I'm not sure in this case that the differences in geometry are that significant.

The Fortress might, in Mantus eyes, not cut the mustard but the Mantus shank has 25% of its strength.

I appreciate that many do not like the idea I have maintained a focus on one specific product but my previous post underlines the reason. I think that if the shank is based on the steel grade quoted then it has not been manufactured to the strength that might be expected. I was also concerned about the 'remove the roll bar' video. If it is not safe for the roll bar to be removed for 100% of the people 100% of the time then some cautionary note should be produced - it has not happened. I had hoped that the facts would be looked at, addressed swiftly and quietly, and that it would all go away. That has not happened - hence my persistence. If you like the idea of anchors with shanks able to withstand 100kg for 35' yachts then I understand you will think I am a nuisance. If you think airing a video that might not be 100% safe is acceptable - then you will not like my persistence.

I thank you for your patience and tolerance and humbly apologise as I have obviously upset some of you.

I'll leave the thread pending Mantus quantification and explanation of the video.

With warm regards,

Jonathan

Forgive me for asking the hard questions in an effort to uncover the truth, but if you are not a professional yachtsman then why do you describe yourself as an "Independent Maritime Professional" on your Linkdin page?

This statement implies you possess a level of expertise and knowledge beyond any of us amateurs.

I don't deny you the title of "Marine Journalist" as you have been published but I do question your qualification in this respect given your background is in Geology and not Journalism.

Boatman61 is a maritime professional, Resinhead is a maritime professional, as are many others here.

If you have some legitimate reason to make such a claim, great. If not it strikes me as a bit of an aggrandizement. The only motivation I can think for this is you want to sell more stories which seems rather insincere for someone who calls himself a journalist.

[congo]

Well ,well Cotemar.

The AR Team, has a nice ring to it -I only wish it was true with the nominies you have presented, only thing is I think you have left out Brian from Fortress, there is only myself and my family, (the AR team) a small company that I am sure poses no threat to anyone.

As far as Mantus goes I could not care what they put in their shanks as it will not prevent the initial function of his anchor, as a company with twenty years of experience in roll bar design, I have a genuine concern for all the customers saftey, Greg must clarify what he means with or without the roll bar,you either do or dont need it full stop.

From all of my experience with roll bar design, the Mantus in it's current form will if used with the roll bar removed be subject at sometime or another, adapting an upside down positon, this is not uncommon for any anchor, but because Mantus is design purpose to correct itself with roll bar attached,without it will stay extremely stable upside down.

I have nothing against Greg, anyone that can design, develop new product should be encouraged, no one is trying to discourage his efforts just asking for clarification.

At least Cotemar you have exposed your agenda, it explains your ridiculous comments.

Quite often moderators interviene and remind all to stop accusing, Knocking, to prevent a forum fight, Cotemar as a moderator you should follow suit and get your manners back in order.YOU HAVE CLEARLY INSULTED MANY.

Regardless it looks like one of your AR team has left the building so that should be a relief, for me, AR will just continue to built strength, performance and quality into our product over price, this is why we are twenty years plus young.

Regards Rex.

[Delfin]

Originally Posted by Cotemar

This thread was started by windswepttom (The OP=original post) who had a great experience with his new Mantus anchor.

This thread has now turned to an AR team against Mantus Anchors.

No one has ever reported a bent shank to Mantus, but the AR team feels it there duty to take down any anchor competition.

Mantus Anchors currently use mild steel shanks and are transitioning over to high strength ASTM A514 (780 MPa steel yield strength) alloy shanks. They have never had a claim for a bent shank and have a Lifetime Guarantee. http://www.cruisersforum.com/forums/f102/its-true-the-mantus-65-lb-hooks-first-time-everytime-110154-6.html#post1368769

For those who do not know ASTM A514 (Mantus new shank material) is equivalent to Bisplate 80 (AR excel shank material).

For anyone following this anchor conundrum, this may clarify the AR team.
JonJo = writes anchor reviews giving AR anchors top ratings and support
Congo = CEO of AR Australia
Factor = has and AR excel anchor and defends them like no other
Delfin = does not have an AR excel anchor, but thinks they are the best
Downunder = has and AR excel anchor and defends them like no other

This AR team keeps repeating their questions on this thread and then another one will come in and re-affirm what they feel should be the answer.

To the OP that started this thread, sorry that the AR team has taken charge of your thread and turned it from a good experience into a bad one. They had done this on a few anchor threads last year also, so you’re not alone.

Weird-o-rama....

[Delfin]

Originally Posted by congo

Well ,well Cotemar.

The AR Team, has a nice ring to it -I only wish it was true with the nominies you have presented, only thing is I think you have left out Brian from Fortress, there is only myself and my family, (the AR team) a small company that I am sure poses no threat to anyone.

As far as Mantus goes I could not care what they put in their shanks as it will not prevent the initial function of his anchor, as a company with twenty years of experience in roll bar design, I have a genuine concern for all the customers saftey, Greg must clarify what he means with or without the roll bar,you either do or dont need it full stop.

From all of my experience with roll bar design, the Mantus in it's current form will if used with the roll bar removed be subject at sometime or another, adapting an upside down positon, this is not uncommon for any anchor, but because Mantus is design purpose to correct itself with roll bar attached,without it will stay extremely stable upside down.

I have nothing against Greg, anyone that can design, develop new product should be encouraged, no one is trying to discourage his efforts just asking for clarification.

At least Cotemar you have exposed your agenda, it explains your ridiculous comments.

Quite often moderators interviene and remind all to stop accusing, Knocking, to prevent a forum fight, Cotemar as a moderator you should follow suit and get your manners back in order.YOU HAVE CLEARLY INSULTED MANY.

Regardless it looks like one of your AR team has left the building so that should be a relief, for me, AR will just continue to built strength, performance and quality into our product over price, this is why we are twenty years plus young.

Regards Rex.

Speaking of Team AR, when I joined I was promised a gun and a badge and to date, I have neither. I left those losers at Team Fortress because all I ever got from them for a lousy baseball hat and a ticket to a hockey game. I am currently entertaining an offer from Team Hydrobubble, so I would get going on at least the badge if you expect my continued support.

[congo]

Well Delfin.

Sorry about the badge as they were more expensive than I though, the gun yea, well you are dangerous enough on the forum, I decided againt it sorry.

But as you know as time goes by their will be plenty of more reports on our fabulous anchors on this forum, so the A Right team will grow and I hope someday will be rewarded with another man of your integritty, after all we do need Cotemizers.

Regrds Rex.

[Mantus Anchors]

Originally Posted by congo

Well ,well Cotemar.

The AR Team, has a nice ring to it -I only wish it was true with the nominies you have presented, only thing is I think you have left out Brian from Fortress, there is only myself and my family, (the AR team) a small company that I am sure poses no threat to anyone.

As far as Mantus goes I could not care what they put in their shanks as it will not prevent the initial function of his anchor, as a company with twenty years of experience in roll bar design, I have a genuine concern for all the customers saftey, Greg must clarify what he means with or without the roll bar,you either do or dont need it full stop.

From all of my experience with roll bar design, the Mantus in it's current form will if used with the roll bar removed be subject at sometime or another, adapting an upside down positon, this is not uncommon for any anchor, but because Mantus is design purpose to correct itself with roll bar attached,without it will stay extremely stable upside down.

I have nothing against Greg, anyone that can design, develop new product should be encouraged, no one is trying to discourage his efforts just asking for clarification.

At least Cotemar you have exposed your agenda, it explains your ridiculous comments.

Quite often moderators interviene and remind all to stop accusing, Knocking, to prevent a forum fight, Cotemar as a moderator you should follow suit and get your manners back in order.YOU HAVE CLEARLY INSULTED MANY.

Regardless it looks like one of your AR team has left the building so that should be a relief, for me, AR will just continue to built strength, performance and quality into our product over price, this is why we are twenty years plus young.

Regards Rex.

Rex, thank you for your interest in our marketing strategy
So let me restate an interesting feature of the Mantus Anchor, there are plenty of small boat fisherman, recreational day users, kayakers that have room constraints and prefer to use the Mantus without the Roll Bar...
It works great It lands right every time and if used with a bit of chain is really difficult to flip on resetting... Video coming....Certainly works better than the Danforth, these guys are accustomed to and this why we are capturing this market... You might want to look into it...
Let me know if I can offer any other advice...

Now remember its sold with the Roll Bar... So you can bolt yours together

Greg

[JonJo]

Greg,

Great stuff, very impressive.

I certainly do not think the analysis is a waste of time.

Can I query the Mantus analysis? - but no great hurry, enjoy the shower

The Mantus HT has a load to bend of 600lb and the Mantus MS has a load to bend of 300lb. Based on minimum the YS of A514 is 690 MPa and the YS of A36 MS is 250 MPa. I confess I do not know the typical or average YS of MS, but I could look it up - I'm sure Google will find it. In the meantime can you explain why the loads to bend are not relative or in proportion to the YS.

Can you also advise how you identified the steel used, or its YS, on the Delta

Will you be including an analysis of the Rocna (Q620 and Bis 80?), Excel and/or Supreme. You have chosen sizes of anchors of which I am unfamiliar - 45lb is a bit bigger than I handle, and I have measurements only of the Rocna, 20kg. You have also chosen anchors I have never actually seen, like Danforth and the elusive Boss.

But great work

Jonathan

[s/v Beth]

Well cotemar may have insulted many, the experts on this thread have shown their true colors. To try to shame a moderator into accepting your bulling is a new low. They work their asses off to make this forum civil. Civil enough to you to give your opinion again and again.
OK we know how you feel.
But a few of us are considering the Mantus seriously.
And I for one would ask you politely : if you have a mantus I want to hear about your experiences with it.
If you don't have a mantus- please go start your own thread.
I think that is what the op was trying to do, and I happen to think that's a good idea.

[d.taylor]

Originally Posted by JonJo

D. Taylor

Knocking the competition does not earn you brownie points - it might make you smile (to knock them) - but Fortress have thousands of happy customers - your knocking their favourite anchor does not engender love and respect.

Jonathan

When did I ever say anything negative against Fortress?
Or is “knocking” an Aussie word for Structural Analysis?

My only objective has been to reconcile the disconnect between the analytical methods you published in the PS article & the analytical methods traditionally used in engineering.
(Ref Wiki: Bending - Wikipedia, the free encyclopedia)

This disconnect was especially puzzling to me because I am very familiar with simple beam bending analysis & have used it many times to perform initial sizing for airframe & spacecraft structure. It works really well for rough order magnitude sizing before optimizing structure with 3-D Finite Element Modeling.
In order to resolve the disconnect I needed one-to-one examples. You had Rocna numbers is your article so they were the lucky first example. Fortress was just an easy second example for a few reasons – their shape fits classic beam theory very well & I had dimensions readily available & you offered up your prediction for bending strength using your methods so I had something to compare to. A Danforth would have been another perfect example but you never posted a prediction for Danforth’s bending strengths.

But I have now identified the errors in your equation. So no need for any more comparisons.
The first problem is just a random factor of 1/10 added. Make the equation 1/3… instead of 1/30…. And now your math works. The bending strength result is still not accurate but your math does work at least (inputs = outputs)

The second one is the incorrect use of “I”, area moment of inertia. It is important to use “I” with respect to the neutral axis. For a rectangle, this is easy; the neutral axis is the centerline. Jonathan, the “I” you used was with respect to the edge. (see pic below & ref wiki link).
List of area moments of inertia - Wikipedia, the free encyclopedia

Note also that “y” (or as I referenced as “c” in my earlier post) is the distance from the neutral axis to wherever you want to calculate the stress. For our calcs we are interested in max stress, which is at furthest fibers.
So y = ½ thickness.

If you look at the Wiki links, the derivation will be obvious. And now you will be calculating accurately (within the appropriate conditions associated with simple bending theory)

Originally Posted by JonJo

D. Taylor

If you have an issue with declaring your shank strength, please advise, but having spent so much time analysing a Fortress why are you so reluctant to quantify your own product?

Jonathan

Like I said Fortress is easy – straight bar, constant taper. Only thing easier would be a Danforth.
Greg posted 3-D results, I'll post 2-D tomorrow. Patience, Patience - some of us have day jobs..
Besides now you have time to update your numbers.