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Old 07-31-2013, 07:12 PM   #21
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The main reason is probably just to help the anchor set. Once it's set and if the rode gets straightened out in a big blow loosing it's catenary there's not any reason or benefit for having chain in your rode as far as holding power is concerned. But of course there is swinging room, convenience ect ect.

but but but even if the chain is straightened out gravity still sucks. The weight of the chain is still there , just no spring left.
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Old 07-31-2013, 07:22 PM   #22
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but but but even if the chain is straightened out gravity still sucks. The weight of the chain is still there , just no spring left.
And that actually reduces holding power as it puts tension on the chain and your anchor is more likely to break out. You want that anchor to be resisting the pull of your boat in the wind not to hold up chain.
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Old 07-31-2013, 07:56 PM   #23
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Once again...the bar tight argument...If you are anchoring in conditions where the chain is bar tight (which are conditions that are probably chaffing through your nylon at an alarming rate) without a long, adjustable snubber...or safe at some dock like I always seem to be...then you deserve to be dragging your anchor...

How can the same misguided argument persist forever....if your chain is bar tight...probably so would be a synthertic rode ....and most cruisers employ a snubber that takes the shock...the biggie is that a cheap snubber is chaffing and not your expensive synthetic rode.

Unless you are the one in a thousand cruisers that actually employ great chaffing gear.

Don't lecture me on how many DO employ good chaffing gear...remember I'm in the salvage business and profit from boaters who have chaffed through their "great" chaffing gear.
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Old 07-31-2013, 08:21 PM   #24
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And that actually reduces holding power as it puts tension on the chain and your anchor is more likely to break out. You want that anchor to be resisting the pull of your boat in the wind not to hold up chain.

Are you implying that in this situation a nylon rode would be better than an all chain?
If so, I'm interested in learning why. I realize that it may be a long explanation and don't expect you to spend a lot of time explaining it to me, so is there somewhere on the internet that you know of that I can reference?
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Old 07-31-2013, 08:23 PM   #25
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Well let's hear it. In a 50 knot blow does the catenary get pulled out or not. I thought we as a group decided it did. I personally don't think so but if it pulled straight enough so very little catenary was left one could call it "bar tight". If there was 1/16" of catenary the angle of pull would basically be straight so the 1/16" isn't worth talking about. As I said this whole "bar tight" thing came from the Rocna Smith guy so ????
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Old 07-31-2013, 08:29 PM   #26
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psneeld,

I use a bridle and several people on the docks have said it's one of the best ones they've ever seen. This has given me a sense of confidence when anchored.

However, your comment about a long, adjustable snubber got my attention. Do you have a picture or a website I can refer to? I may be interested in changing my set-up

Also, I have chaffing gear, but I don't have any idea whether it's great or not. Can you give me reference on that also?
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Old 07-31-2013, 08:44 PM   #27
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psneeld,

I use a bridle and several people on the docks have said it's one of the best ones they've ever seen. This has given me a sense of confidence when anchored.

However, your comment about a long, adjustable snubber got my attention. Do you have a picture or a website I can refer to? I may be interested in changing my set-up

Also, I have chaffing gear, but I don't have any idea whether it's great or not. Can you give me reference on that also?
No websites , just experience.

I use a single snubber and not a bridle...but that may change. The concept of adjustable is that the leg(s) are long enough that if you had to sit out a blow...you could keep letting out a few inches per hour(s) so the same part isn't working the same chaffing points...let out a few links of chain too.

For chafe I just use clear vinyl tubing that the line easily slides within...just use a tie wrap to secure it in the strands of 3 strand. They break but I just replace them...duct tape if they break in a blow and you need to secure the hose.

As a trawler guy who will probably never really sit out a blow at anchor (just too good enough WX info here on the East Coast) all this talk of bar tight and 100 pound anchors just makes me smile...now If I was back in Kodiak, AK and worried about Williwaw..then yes I would have a 120 pound anchor...still all chain...and rig several snubbers when expecting the worst...but even then I would be headed for safe harnor if Williwaw conditions were forecast.
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Old 07-31-2013, 08:54 PM   #28
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Got it. And, thanks for the reply.

My bridle is pretty long, so I would be able to adjust it.
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Old 07-31-2013, 09:02 PM   #29
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It's amazing how any aspect of anchoring can get peoples panties in such a knot. Must be because the variables are essentially infinite. Then again, heated debate is understandable when considering the advice I got from a fellow today who said, "Just let out 20% more line than how deep it is. So, if you're anchoring in 70 feet, let out about 90 feet of line. Also, clip a 10 pound weight near the end of your chain...that'll keep the anchor down".
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Old 07-31-2013, 09:02 PM   #30
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Got it. And, thanks for the reply.

My bridle is pretty long, so I would be able to adjust it.
Most of the time chafe adjustments are in inches... so as long as you don't let chafe get out of hand...you can just keep feeding it out a couple inches hopefully every half hour to hour....
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Old 07-31-2013, 09:07 PM   #31
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It's amazing how any aspect of anchoring can get peoples panties in such a knot. Must be because the variables are essentially infinite. Then again, heated debate is understandable when considering the advice I got from a fellow today who said, "Just let out 20% more line than how deep it is. So, if you're anchoring in 70 feet, let out about 90 feet of line. Also, clip a 10 pound weight near the end of your chain...that'll keep the anchor down".
Much of the "panties in a knot" comes from when someone thinks their method is the only one that makes sense and has all the "right stuff"..when obviously most cruiser's anchoring habits are all over the map...so will their ground tackle be.

Especially when one want's to argue something like "that's the only benefit" when many posters in many threads have posted why they like or dislike dozens of feature s of all chain or mixed rodes. Most of the "all chain" gang have repeatedly responded that their snubbers are in effect a "mixed rode" setup....but when someone is conviced their's is the only way...disussing all other setups just falls on deaf ears.
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Old 07-31-2013, 10:53 PM   #32
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Nsail,
No there isn't. I have thought about this in the past but not to any great depth. But earlier today talking about catenary I thought about it a bit more and yes as far as I can see now it may mean that lots of chain may be reducing anchoring performance.

Consider a chain fastened to two cars. How much tension will it take to pull that chain up off the ground and make it reasonably straight? If the chain is what trawler skippers usually use anchoring at 5-1 scope as they say they do and the water was 43' deep it would require about 250' of rode. If that rode was 5/16" chain and the chain was fairly straight How much tension do you suppose it would be exerting on the 2 cars? I'm thinking hundreds of pounds but it could even be more.

Now lets imagine a trawler at anchor w the wind blowing hard. There is a lot of tension on the rode. The boat is pulling on the rode because of the wind and current (if there is any). The pull is transmitted to the anchor. But also the weight of the chain (200lbs?) is pulling on the boat and the anchor. Perhaps hundreds of pounds. So the anchor needs to resist the tension resulting from the weight of the chain AND the pull of the boat in the wind.

Nylon anchor line weighs nothing compared to chain so it would seem to me that chain on the anchor rode may have 100 or perhaps several hundred pounds of pull being exerted on the anchor that would not be there if the rode were nylon.

This pull from chain weight is probably more negative than the catenary is positive. Especially in extreme conditions. So as long as you can get an anchor to set it looks like chain would help dislodge it and the more tension on the rode the greater the force that is trying to break out the anchor.

I remember Marin swore by his "all chain rode" and thought his Bruce anchor was the reason he dragged. Perhaps he wouldn't have dragged had he had nylon?
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Old 07-31-2013, 11:13 PM   #33
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Wow Eric! Thanks for that answer. I really didn't expect you to fully explain it, as I had a feeling it would be a long explanation.

At any rate, I now understand the theory and it gives me something to think about.
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Old 08-01-2013, 06:27 AM   #34
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Wow Eric! Thanks for that answer. I really didn't expect you to fully explain it, as I had a feeling it would be a long explanation.
At any rate, I now understand the theory and it gives me something to think about.
Something to think about, indeed...
I'm sorry - tried to resist, but just had to come in here. Long live the lively anchor stousch.
I certainly would recommend re-thinking it - long and hard, and you as well my dear Eric, old friend, because I think your theory is just wrong.
With all due respect your analogy of pulling the rode taut between two vehicles is just not comparable. The protection the heavier chain rode gives is from the catenary, and the extra tension/load it takes to lift it off the seabed, which if all chain is a lot - way more than a comparable length of synthetic rope rode. But this protection of the anchor from being subjected to a direct pull on the shank, only lasts up to the moment it is finally pulled straight. When you reach that point, then whether the rode is nylon or chain, you just have the pull of the boat transmitted straight to the anchor, and the composition of the rode is almost irrelevant, as it is then just becomes one very strong 'string' pulling on the anchor. It is then that the weight of the anchor, and how deeply it has bedded in becomes the critical factor, but not until that point, because until then it has really just been locating the end of the rode.
Sure up till then it has been resisting the weight of the rode, but until the rode is effectively lifted clear of the bottom, it really has not been feeling much of the actually pull of the boat, just the weight of the rode, and then not so much until nearly all is lifted because of the friction between that still on the bottom and the mud etc still gripping that chain. And, don't forget, the pull is never constant, and the second there is any let-up, the weight of the rode pulls large lengths of it back to the bottom. So it stands to reason, the more weight in the rode, within reason, the longer it will be and the larger the force must be before the anchor is subjected to the full load of boat which includes the force needed to lift the rode, surely. The lighter the rode, the earlier it will be pulled effectively straight and the full pull of the boat go on the anchor.
To take the comparison one step further, the ultimate full force the combined elements are capable of transmitting to the anchor, once the rode is straight, by definition must include the effort/tension required to lift the rode off the seabed, so one can subtract that from the ultimate force of the pull, meaning the net force the boat can exert is the total force minus the force to straighten the rode...which relates directly to its weight...you do the math, as you US guys say...
My case rests....
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Old 08-01-2013, 06:53 AM   #35
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With PeterB on this one..he is using the same explanation (tho not in an automaton way but in a independent thinking way) that millions of boaters and seaman who have gone before also agree with.

I know better too.... so until someone can explain with vectors and forces that chain is evil...I'm willig to go with the millions of boaters who think chain helps keep an anchor...well...anchored....maybe not in every situation..but in what we really see on a regular basis.

As I posted before (and so did Peter)....LONG before the chain becomes bar tight...nylon will be the same,,,the only difference is it will stretch...they will be exactly at the same angle and exerting the same force (shock forces may vary)....

The holding power of the anchor is based on bottom makeup, fluke area/resistance and angle of pull (based on scope)....not anything to do with rode makeup.

Being the devil's advocate...the ONLY advantage of a nylon rode is that it absorbs shock loading...but that is remedied in an all chain rode with a snubber...

See...now doesn't that sound really dumb? All experienced cruisers (no matter what kind of rode they use) know better...there are other advantages to nylon rodes...if you think about them.
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Old 08-01-2013, 07:27 AM   #36
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It sure looks like Peter B is the only one here who has read some of the many studies performed on mooring dynamics for the shipping and offshore industries.

There are no more mysteries, this subject is so critical to the offshore industry that a huge amount of money and effort has gone into understanding how a mooring works for all materials and depths.

Has anyone ever noticed that chain is not a single continuous strand? It is collection of individual segments that function independently until a certain system shape is obtained ... think about it.
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Old 08-01-2013, 08:34 AM   #37
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I can understand your thinking Eric, but I think Peter's clearly worded points out weigh yours.

Still - I dont have all chain, due to lack of a suitable windlass, but try to make up for it with extra length nylon rode and a beefy anchor.
I defimitely think on the first 20 or 30 ft it is critical for chain, not only to keep the pulling angle low, but to minimise possible damage of the rode from chaffing on reefs.
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Old 08-01-2013, 08:45 AM   #38
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Wow Eric! Thanks for that answer. I really didn't expect you to fully explain it, as I had a feeling it would be a long explanation..
I wouldn't accept this answer, literally, if I were you.
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Old 08-01-2013, 09:37 AM   #39
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Rock climbing ropes have a "fall rating", which is the number of hard leader falls one can safely withstand before the rope should be retired because it has become unsafe due to deformation/damage to the fibres in the rope. Is there an equivalent "storm rating" for nylon rode? I've never seen one mentioned...
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Old 08-01-2013, 10:37 AM   #40
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Rock climbing ropes have a "fall rating", which is the number of hard leader falls one can safely withstand before the rope should be retired because it has become unsafe due to deformation/damage to the fibres in the rope. Is there an equivalent "storm rating" for nylon rode? I've never seen one mentioned...
I believer there is a "stretch" limitation...once it reaches that the "breaking and or working loads" are supposed to be reduced or I forget if the rope is no longed considered "serviceable"

Because the "stretch" limitation should come from a given load...I would think a rough calculation would do the same thing...can't find a quick and better explanation...but I know I have seen it when discussing marine line, anchor lines, etc...
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