Mantus rode

[Dockhead]

Originally Posted by Kelkara

I still think there's more I can learn from this thread ... so I'm going to throw in one more example and question ... using a CQR in 10m of water and 5:1 all 6mm chain getting hit by 40 gusting 50 knots I started dragging, but increasing to 10:1 with 50% nylon rode and I stopped.


how much do people think that the extra scope helped, and how much help do you think I got from the extra snubbing in the gusts I got from having about 5x as much snubber length in the nylon rode?

The CQR is notorious for being intolerant of any slight angulation, so should always be used with excessive scope.



I consider myself something of an expert on dragging CQR's, as I dragged mine several times a year during about 10 years of cruising in the '90s.


Please have a look at the videos by Panope and by Noelex showing the setting and holding behavior of CQR's by direct observation. When your hair stops standing on end, go and order yourself a better anchor.



The anchor is really 90% of your ground tackle. If you have a good and large anchor, and a way to be sure that any snatch loads are properly snubbed, then everything else, including type and amount even of rode, is only another 5% of the equation.



The first anchors designed after the CQR, incidentally, concentrated on better tolerance to angulation. The original Bruce, for example, claimed to maintain 50% of its holding power down to 2:1 scope.

[Kelkara]

Originally Posted by Dockhead

Please have a look at the videos by Panope and by Noelex showing the setting and holding behavior of CQR's by direct observation. When your hair stops standing on end, go and order yourself a better anchor .

That wasn't my question ... replacing the CQR was one of the first things I did on the boat ... but I still believe that any anchor can find a bottom that it will perform poorly in, it's just easier to find that bottom condition with a CQR.

[Dockhead]

Originally Posted by Kelkara

That wasn't my question ... replacing the CQR was one of the first things I did on the boat ... but I still believe that any anchor can find a bottom that it will perform poorly in, it's just easier to find that bottom condition with a CQR.

Indeed, and that's a good way to put it. But besides that, CQRs have a noted sensitivity to angulation, which I was offering as an explanation to your experience and answer to your question.

[ramblinrod]

Originally Posted by Delfin

Rod may be onto something with the recommendation he gives his clients that you need to carry 10:1 worth of rode for your maximum anchor depth. For me, I think last season that would involve around 1200 feet of 1/2" chain, in the which case, I don't really need an anchor at all. Just dump 2,800 ponds of chain over the side and go to sleep. With a half mile of chain on the seabed, who needs an expensive anchor at all?

Delfin,

Your posts are argumentative, inflammatory, and intended to insult or discredit, and they are completely baseless in my opinion.

Knock it off.

I have never, ever stated, nor would I likely support, what you claim.

If someone wants to behave stupidly, on their boat, that is their business.

If they want excellent advice on ground tackle, that's mine, and I take it very seriously.

If a customer requests my consultation on ground tackle, I will review their boat design and configuration, and consult them to determine their wants and needs, and then recommend a number of options, that I am willing to supply / install / support.

If they ask me to do something I disagree with in principle I will advise so. If it is so severe I do not wish to support it, I respectfully decline.

If they don't heed my recommendation, and short scope their anchor to gain acceptance by others who have no skin in their game, and their boat founders, my conscience is clear.

I cannot explain why using the amount of scope recommended by the majority of experts, seems to be so complicated or mysterious or convoluted to others who should know better, including some who claim to be experts themselves.

[Kelkara]

Originally Posted by Dockhead

Indeed, and that's a good way to put it. But besides that, CQRs have a noted sensitivity to angulation, which I was offering as an explanation to your experience and answer to your question.

Thanks. To be fair in that case the CQR didn't break out of the bottom, it was just plowing a furrow.

My thought was that it may have been dragging most while dynamically stopping the boat surging during gusts, and that it was the easing of these forces due to the extra nylon that brought the drag under control, with the change in angle due to the scope increase playing less role.

But if a CQR regularly underperforms at 5:1 even in good holding, then I guess scope is the answer.

[ramblinrod]

Originally Posted by Q Xopa

Hmmm, crying victim, again. Honestly I cant see anything remotely insulting. Claiming this to me seems ridiculous.

Everyone here is entitled to their opinions. I especially like hearing ones being esposed by numerous experienced and respected posters that back up with their experience and well reasoned logic and references.

The fact that you so often seem to be at odds with so many other respected contributors offering well considered advice so often seems to be a remarkable coincidence.

Again opinions are fine.

Disagreement is fine.

Disrespectful behaviour is not.

Why am I at odds so frequently with those who tend to bully others on this site?

Because I am willing to stand up for what I believe in, despite knowing the retribution and backlash I am going to receive from certain members, whereas others will not, and THAT is a damn shame.

However, seeing the f'ing abuse I have to endure EVERY time I disagree with certain individuals on this forum I most certainly don't blame THEM at all.

[Dockhead]

Originally Posted by Kelkara

Thanks. To be fair in that case the CQR didn't break out of the bottom, it was just plowing a furrow.

My thought was that it may have been dragging most while dynamically stopping the boat surging during gusts, and that it was the easing of these forces due to the extra nylon that brought the drag under control, with the change in angle due to the scope increase playing less role.

But if a CQR regularly underperforms at 5:1 even in good holding, then I guess scope is the answer.

An anchor should never, ever "plow a furrow" through the bottom -- that is just a ridiculous anchor fail. A good anchor is either set, or not, and doesn't have an intermediate "plowing a furrow" stage. If it will take a full power backdown for two or three minutes, it's set.


When my Father is on board, my anchor setting routine bothers him -- "you'll pull the anchor out, son!" To which I say "Yeah, and if I can, it's not set!" Of course he doesn't listen


More times than not, I dragged my CQR when the wind was over 30, even completely buried in clean sand. I can't count the number of times it happened.


When I changed to Spade in the late '90's, the dragging stopped. In 20 years since then, excluding charter boats (a whole nother story), over tens of thousands of miles of cruising, with a variety of Spades, a Rocna, and one Delta -- I have dragged -- ONCE.


That one time was a couple of years ago on the island of Gotland in the middle of the Baltic, after a long single hand passage from Sweden. The bay I chose for anchoring turned out to have thin sand over a hard smooth stone bottom, and I just couldn't get the anchor to set. The weather was calm, I had plenty of room in the bay, and I was exhausted, so rather than going back out to sea, I decided just to get it hooked as best as I could, dump all the chain out onto the sea bed, set all the alarms (radar and anchor drag), and go to sleep.


I was awakened the next morning, blessedly 8 hours later, by the sound of the anchor and 100 meters of chain dragging slowly across stone. I got up, brushed my teeth, dressed, started the engine, weighed anchor, and set off for my next stop, Faro.


And that was the only time. I think it is realistic to expect your anchor to simply never ever drag, provided you take enough care setting it (including lengthy backing down and using maximum revs finally), and have flat and at least "medium" bottom conditions.

[Dockhead]

Originally Posted by ramblinrod

. . . I cannot explain why using the amount of scope recommended by the majority of experts, seems to be so complicated or mysterious or convoluted to others who should know better, including some who claim to be experts themselves.

A majority of experts recommend using 10:1 all the time? Or saying that more scope is always better? I don't think I ever read even one expert saying anything like that. Maybe you could share some references.

[StuM]

At it again I see

Originally Posted by ramblinrod

Quote:
Originally Posted by Delfin
Rod may be onto something with the recommendation he gives his clients that you need to carry 10:1 worth of rode for your maximum anchor depth.


Delfin,
I have never, ever stated, nor would I likely support, what you claim.

Post #8

Originally Posted by ramblinrod

...
Rule 6: Total rode length. For the standard rode, this needs to be at least 10 times the maximum depth + bow height, you ever expect to anchor in.

E.g., For bow height = 5 ft and max depth = 25 (Florida and Bahamas) you could get away with Rode Total = (5 + 25) X 10 = 300 ft.

To anchor in 50 ft of water, you should have Rode Total = (5+50) x 10 = 550 ft.

Some who use all chain rode, may claim less is acceptable. I disagree.
Hope this helps.

[Delfin]

Originally Posted by StuM

At it again I see






Post #8

That's the beauty of the Internet and forums like this. You can take most any position on most any issue, find out you are wrong, then 150 posts later argue exactly the opposite and posture as if you were right both times.


If Rod1 recommended carrying 10:1 with all chain rode, and Rod2 never said any such thing, what does Rod3 have to say about the issue?

[Delfin]

Originally Posted by ramblinrod

Delfin,

Your posts are argumentative, inflammatory, and intended to insult or discredit, and they are completely baseless in my opinion.

And yet, while whining about being disrespected, you insult anyone (which is everyone) who disagrees with you. Like this:

Originally Posted by ramblinrod

If someone wants to behave stupidly, on their boat, that is their business.

That is pretty much a repeat of calling DH's anchoring in Greenland "dangerous", and both statements should be withdrawn, because they are "argumentative, inflammatory, and intended to insult or discredit". That is your intent, is it not?

Originally Posted by ramblinrod

I have never, ever stated, nor would I likely support, what you claim.

Stu has already quoted when you stated exactly that, so saved me the trouble.

Originally Posted by ramblinrod

If they want excellent advice on ground tackle, that's mine, and I take it very seriously.

How can you possibly assert that you give excellent advice if the advice you give is contradicted by yourself as something you would "never, ever" state?

Originally Posted by ramblinrod

If a customer requests my consultation on ground tackle, I will review their boat design and configuration, and consult them to determine their wants and needs, and then recommend a number of options, that I am willing to supply / install / support.

Then I sincerely hope that anyone fool enough to listen never plans on venturing much beyond the marina.

Originally Posted by ramblinrod

I cannot explain why using the amount of scope recommended by the majority of experts, seems to be so complicated or mysterious or convoluted to others who should know better, including some who claim to be experts themselves.

I can help with that. The reason everyone is fairly emphatic on disagreeing with most of what you write is because they do not want others who are trying to learn to think that what you are writing is advice any sensible mariner would follow. More in the realm of public service than bullying.

[hpeer]

Dock head,

Your analysis made feel a lot less stupid about my 125# Mantus.

Thanks!

Somewhere else I said I think of the ground tackle this way:

1-The anchor hooks you to the bottom.
2-The chain/rose hooks you to the anchor.

If your chain/rode is strong enough for the greatest likely wind it’s good enough ( considering chaff on coral etc)

But the anchor needs to develop that resistive force in a very wide set of circumstances. So figure your worst possible set ( ignoring 1” sand on bare rock or baby poo mud) and buy the anchor accordingly.

My rough rule of thumb for next gen anchors, and it’s not completly linear, is 6# per ton. I would go with more weight for light boats because light anchors have a hard time breaking through grass and hard sand. Lighter in heavy boats.

The more I read these threads I think that works pretty well, if a bit conservative.

[Kelkara]

Originally Posted by Dockhead

An anchor should never, ever "plow a furrow" through the bottom -- that is just a ridiculous anchor fail. A good anchor is either set, or not, and doesn't have an intermediate "plowing a furrow" stage. If it will take a full power backdown for two or three minutes, it's set.

That's perfectly true. I'm not going to try and defend the CQR, that's just what I had at the time, and it was set as well as a CQR does set. But my engine is not as powerful as 50 knots of wind, so backing down will not tell me how the anchor will perform under those loads.

Lengthening scope was the most obvious thing I could think of ... so I just let out everything I had, and since I was already at the end of my chain, the extra was all nylon ... running the engine all night was going to be my next move, but I had the swinging room and the extra rode worked.

This would seem to support the conclusion that more scope is better. But I like to play the "what if" game ... and this thread has made me think ... "what if" that extra rode had been all chain instead of nylon, would I have seen the same difference? extra scope just reduces the angle of pull on the anchor, but extra nylon will soften the dynamic forces as the boat tugs on the anchor ... my hypothesis is that just by reducing the angle of pull, the CQR would have just kept on ploughing because that's what CQRs do best if you pull hard enough ... but by effectively using a better snubber the peak shock loads were kept below the failure point and the anchor could continue to work. In gusty or bouncy conditions is there a case that lengthening the snubber is a better option than simply lengthening scope?

Had it been a better anchor in poor holding, rather than a CQR in good holding (apart from the fact that the failure mode would have probably been a catastrophic release rather than a slow steady plough) would the situation have been different? Obviously, not anchoring in poor holding is key ... but occasionally I misjudge what I'm hooked into.

[ramblinrod]

Originally Posted by StuM

At it again I see






Post #8

Yes, did you see the qualifying example right under that?

Anyone should realize there are practical limits; I mean if someone claims to want to anchor in 100 ft, well, that's a stretch, but 1000 ft, c'mon.

Notwithstanding if a customer advised they wanted to anchor in 100' regularly, I would have no problem recommending 500 ft of chain and another 500 ft of nylon if the vessel could support it.

Why not have it if you want it and your vessel can support it?

[Delfin]

Originally Posted by hpeer

Dock head,

Your analysis made feel a lot less stupid about my 125# Mantus.

Thanks!

Somewhere else I said I think of the ground tackle this way:

1-The anchor hooks you to the bottom.
2-The chain/rose hooks you to the anchor.

If your chain/rode is strong enough for the greatest likely wind it’s good enough ( considering chaff on coral etc)

But the anchor needs to develop that resistive force in a very wide set of circumstances. So figure your worst possible set ( ignoring 1” sand on bare rock or baby poo mud) and buy the anchor accordingly.

My rough rule of thumb for next gen anchors, and it’s not completly linear, is 6# per ton. I would go with more weight for light boats because light anchors have a hard time breaking through grass and hard sand. Lighter in heavy boats.

The more I read these threads I think that works pretty well, if a bit conservative.

I think the 6#/ton is a rule of thumb that probably makes some sense for smaller boats, but doesn't apply when the anchor gets heavy enough. Delfin stays put in most any kind of a blow with 4:1 scope and 176# for a 64 ton boat, and a 384# hook would be more than a bit of overkill, nevermind not fitting.

What hasn't been discussed (that I noticed at any rate) is the importance of snub lines in any anchoring system. I can never remember the formula, but I believe that it is true that if the force on the anchor is dissipated over 4 feet via a stretching snubber, the force is reduced to 25% of what it is if the rode comes up short without the snubber. You could dissipate the force of impact to the ground to near zero of a tank dropped from a building with an appropriate rubber band.

So, IMO, when you talk about ideal scope, the conversation is somewhat meaningless without a discussion of the entire anchor system, including the snubber.