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Old 23-10-2013, 12:37   #211
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So, would you be okay with an anchor shank that was stronger in terms of its resistance to bending, but was as unbreakable as one that was weaker?
Good question but I think your hypothetical is unlikely to be possible in the real world. Bending can be used as a fuse to release loading without ultimate failure. So my answer is I definitely want it to bend. After it bends then the loads on the rest of the anchor go way down. The lever arm loses its moment and the "stuck" anchor is much less likely to fail. Plus if it is not high test steel or alloy the likelihood is it could be straightened without breaking it off. I would only use higher test steel if to increase the ultimate failure withstand in the worst possible case such as right angle load. I care little to nothing about bending. Bending is always better than breaking so why risk it?
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Old 23-10-2013, 13:10   #212
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

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Good question but I think your hypothetical is unlikely to be possible in the real world. Bending can be used as a fuse to release loading without ultimate failure. So my answer is I definitely want it to bend. After it bends then the loads on the rest of the anchor go way down. The lever arm loses its moment and the "stuck" anchor is much less likely to fail. Plus if it is not high test steel or alloy the likelihood is it could be straightened without breaking it off. I would only use higher test steel if to increase the ultimate failure withstand in the worst possible case such as right angle load. I care little to nothing about bending. Bending is always better than breaking so why risk it?
A514 steel comes in a bunch of different subsets, some of which aren't any more likely to break than A36 mild steel, so it is not only possible to get both both resistance to bending as well as breaking, but the right way to build an anchor IMO.

Take a look at the picture of the bent Fortress above and you'll see an example. It is bent and not broken, because the alloy used by Fortress provided tremendous recovery from deflection right up until it can no longer return to its original shape and simply bends. The difference between it and mild steel is that the mild steel bends so much more easily.

You are correct, I believe, on the difficulty of bending HT steel back into shape, but frankly, bending a mild steel shank back after deflection results in so many stress fractures that the only safe thing to do is get rid of the anchor or replace the shank. I also would not feel comfortable with the ability of an anchor with a bent shank having anything close to the holding power of an unbent anchor, so my preference would be to avoid that in the first place.
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Old 23-10-2013, 13:24   #213
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Further to my point, if the anchor is "stuck" I would rather the anchor stayed stuck than have the super non bending shank cause it to break loose. The occurrence of conditions that can bend even the mildest steel shank are too rare to warrant designing to avoid it because of additional unquantifiable risks IMO.

I have seen wars over useless specifications like this in numerous markets. The manufacturer's response are almost always not what the consumer needs. One vendor does it "right" and the other guys pile on with accusations of "cheating" so a race ensues driving costs up and the customer ends up with something less than ideal.

IMO if your boat is in a serious blow such that your anchor bends but does not break or pull out then praise your anchor don't bitch about it. It could have been a lot worse so be happy if you can get a new anchor or shank for free.
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Old 23-10-2013, 13:53   #214
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

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Further to my point, if the anchor is "stuck" I would rather the anchor stayed stuck than have the super non bending shank cause it to break loose. The occurrence of conditions that can bend even the mildest steel shank are too rare to warrant designing to avoid it because of additional unquantifiable risks IMO.

I have seen wars over useless specifications like this in numerous markets. The manufacturer's response are almost always not what the consumer needs. One vendor does it "right" and the other guys pile on with accusations of "cheating" so a race ensues driving costs up and the customer ends up with something less than ideal.

IMO if your boat is in a serious blow such that your anchor bends but does not break or pull out then praise your anchor don't bitch about it. It could have been a lot worse so be happy if you can get a new anchor or shank for free.
Sounds like a strong vote for the virtues of bending anchor shafts. I suspect your decision for such an anchor will be relatively easy to fulfill.
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Old 23-10-2013, 13:59   #215
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

I must continue to be amazed. It now appears that bendy anchor shafts are not only acceptable, they are in fact desirable!

Bet Craig Smith wishes his bendy days were treated this charitably.
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Old 23-10-2013, 14:04   #216
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

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I must continue to be amazed. It now appears that bendy anchor shafts are not only acceptable, they are in fact desirable!

Bet Craig Smith wishes his bendy days were treated this charitably.
Yup, just goes to show that when it comes to Internet forums, expect the unexpected.
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Old 23-10-2013, 14:26   #217
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

Don't act so surprised guys. Deformation is preferable in a lot of different marine situations. A hull that bends to a rock instead of splits open would of saved the Titanic. Maintaining an intact anchor is better than a breakage of a shank, even if the shank shows higher breaking strength. To bend in response to opposition is sometimes desirable grasshopper.
Notice the mangroves- they endure the hurricane by bending down, but are alive and well a week later
So ya, bendage is not as important as ultimate breakage. But I think that has already been said- you guys just have not been listening.
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Old 23-10-2013, 14:30   #218
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

Greg,

The Fortress shank is slightly more complex than a conventional shank, it tapers in 2 planes and it has a bevel on the leading edges. The overall shank length is not the 'lever length' as the shank will impinge on the mud flaps and crown. So it articulates at 'full length' but its lever length is shorter. I did a quick measure and calculation and came up with a load to bend of over 400kg - which seems to agree with actual tests conducted by someone independent of Fortress. They also mentioned it was very bendy, flexible - it would spring back until it reached the bending load. This srpinginess allows the shank to absorb snatch loads. As far as I am aware side loads will be snatch loads. Conversely a mild steel shank lacks any springyness - it simply bends. Delfin raised the issue of springyness in a post some time back.

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Old 23-10-2013, 14:35   #219
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

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Originally Posted by s/v Beth View Post
So ya, bendage is not as important as ultimate breakage. But I think that has already been said- you guys just have not been listening.
Or, perhaps you have not been reading, since strength and resistance to breaking are not mutually exclusive, but characteristic of the best anchor designs, as explained above.
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Old 23-10-2013, 14:48   #220
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

Greg,

As far as I am aware you are still suggesting that the roll bar can be removed and that a Mantus without a roll bar is completely safe - given that the operator is almost definitely not too clear of the conditions under which he will use his anchor, seabed, wind and tide shift etc.

Can you clearly define that roll bar removal is completely safe.

If it is not safe will you be posting the same on the website, removing the video and advsing your historic customers on your mail list that the roll bar must be attached when the anchor is in use.

Once you have clearly defined the position we can leave the issue alone and concentrate on shank strength.

However I am concerned that you are eager to provide shank strength data on competitors products - but not your own. I had fondly imagined that shank strength data would be one of the first calculations done by an anchor maker prior to releasing their anchor to the unwitting public. You are going to find it time consuming to collate measurements on competitors shanks and even more time consuming to measure steel strength parameters - while we are waiting why not take the numbers from your files.

This is not a thread on Ultra, it is not a thread on Delta - it is specifically a thread on Mantus. If there is the need to examine the performance of anchors that have been on the market for years and are standing the test of time - I am sure you will gain much support with a new thread. So can we focus - once we know what strength the Mantus shank it then gives something against which we can compare.

So 2 answers.

Is roll bar removal safe, yes or no. if, no, what strategy have you to warn customers.

What is the strength of the current and then proposed shank of the range of Mantus anchors. If the information is not immediately available - on what did you base your shank strength comments of the shank being safe.

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Old 23-10-2013, 14:58   #221
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I must continue to be amazed. It now appears that bendy anchor shafts are not only acceptable, they are in fact desirable!

Bet Craig Smith wishes his bendy days were treated this charitably.
The issue, as both you and most here know, was that Craig was claiming Rocna anchors were made of a higher grade steel than was the fact.

They lied. No one is saying any manufacturer involved in this discussion is pulling a Craig Smith.

Right? You knew that, right?
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Old 23-10-2013, 15:05   #222
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

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The issue, as both you and most here know, was that Craig was claiming Rocna anchors were made of a higher grade steel than was the fact.

They lied. No one is saying any manufacturer involved in this discussion is pulling a Craig Smith.

Right? You knew that, right?
Yes, I recall that. No one has suggested that Mantus has been anything but forthright in their choice of steel. They've been just a tad bit less forthright in answering Factor's two questions, or JonJo's question on whether using a Mantus without the hoop is truly safe. They certainly aren't obligated to answer them, and why bother since only a small number of folks are curious about the answers.

I, and I believe Factor, were not commenting on those issues, but only referring to the idea proposed that a bent shank on an anchor is better than an unbent shank or that a shank that will bend and not break with one level of force is somehow superior to a shank that will bend and not break at much higher levels of force.

Both concepts seemed novel enough to trigger some surprise.
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Old 23-10-2013, 15:11   #223
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Or, perhaps you have not been reading, since strength and resistance to breaking are not mutually exclusive, but characteristic of the best anchor designs, as explained above.
I have been reading but more than that I also have worked with a lot of steel (more tonnage than all the recreational yacht anchors in the World) and have stated my preferences in a non snarky way. Let's keep this about facts and earnestly held opinions.

No one is saying it is impossible to make an anchor shank that won't bend. It's easy to do if money is no object. But I don't think that is the most important feature of an anchor. In fact, I think it is way down the list of desirable features (holding strength, setting ease, useable in multiple bottom types, cost, etc. are far more important features). Just because a feature is possible does not make it desirable above all else. This is a complex problem with no right or wrong answer. But myopic focus on one thing at the expense of all else seldom leads to an optimal solution. For example, how many boaters choose an anchor too small because the appropriate size is too expensive? And if somebody resurrects the notion that smaller anchors hold better I fear my head will explode.

In all these discussions I have not heard of any shanks breaking. If there is field data on that then we have a real problem to discuss. I think shank ultimate failure should be so rare as to be virtually nonexistent.
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Old 23-10-2013, 15:16   #224
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I, and I believe Factor, were not commenting on those issues, but only referring to the idea proposed that a bent shank on an anchor is better than an unbent shank or that a shank that will bend and not break with one level of force is somehow superior to a shank that will bend and not break at much higher levels of force.

Both concepts seemed novel enough to trigger some surprise.
This is an over simplification of my opinion at best and mischaracterizes what I said. Please don't paraphrase something when quoting exactly is so easy.
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Old 23-10-2013, 15:21   #225
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Re: It's True! The Mantus 65-lb. hooks first time, everytime.

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John,

I could not agree more with your post here... Something akin to...

Company A makes a cell phone with a taser in the unlikely event that you are accosted in a dark alley.... Cell phone companies B-C-D etcetera follow suit because they are losing market share.... BUT.... The calling feature of the cell is disabled while the taser is being armed.... Undoubtedly the most important feature of a phone.... Especially in an emergency...

I would think that 99.9% of the population would prefer to have anchors that set well and fast vs. the increased strength of shanks... NOBODY has a critical emergency or life threatening instance due to the actual bending of a shank.... Pick not grabbing when you absolutely need it to... YOU BET....

This is a compromise in the wrong direction for the intended purpose... We have not even begun the ductile v. brittle discussions either... I own a test lab.... Slow predictable ductile deformations are not considered failures in most cases.... Sudden fractures and changes in structural integrity are considered failures by almost EVERY standard regardless of product...

Greg... If you're interested in a 3rd party laboratory evaluation... Let me know...
I can't wait for that portion of the discussion.

Quote:
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Don't act so surprised guys. Deformation is preferable in a lot of different marine situations. A hull that bends to a rock instead of splits open would of saved the Titanic. Maintaining an intact anchor is better than a breakage of a shank, even if the shank shows higher breaking strength. To bend in response to opposition is sometimes desirable grasshopper.
Notice the mangroves- they endure the hurricane by bending down, but are alive and well a week later
So ya, bendage is not as important as ultimate breakage. But I think that has already been said- you guys just have not been listening.
Yep.

And I thank all you professionals too. Though the formulas are beyond me.
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