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View Poll Results: chain length
30-40ft 15 8.77%
40-50ft 5 2.92%
60-70ft 5 2.92%
70-80ft 6 3.51%
80-90ft 6 3.51%
90-120ft 17 9.94%
120+ft 117 68.42%
Voters: 171. You may not vote on this poll

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Old 13-10-2007, 18:03   #91
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Quote:
Originally Posted by craigsmith View Post
The first concentrates on a limited context which is not relevent, at the expense of the bigger picture, and the second does not bother with any actual calculations, just blindly repeating old lore.

I will re-post this:
Chain, Rope, and Catenary - Anchor Systems For Small Boats

Is "old lore" or "new lore created by an ancohor salesman" more reliable? Hmmmmm.




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Old 13-10-2007, 18:11   #92
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"Theory" like this is pretty hard to get wrong. Nothing here even begins to touch the real world dynamic scenario, but then nobody here is trying to predict the weather or make a call on global warming models. Even Alain Fraysse's work is too simplistic, but it gets to approximately the right conclusions. Rather, the knee-jerk reaction against anything which disputes established lore - horror! - is the danger to be guarded against.

In any case all the "theory" only supports the real life evidence, most definitely "stacking up" when the report is a little more considered than the kellet "takes the load off the anchor". More rational feedback comes from the likes of Steve Dashew, not to mention Spade designer Alain Poiraud and Rocna designer Peter Smith, all with a rather considerable number of serious cruising miles in widely varied international waters, not to mention qualified technical knowledge - but who are not afraid to step away from the tradionalist myths when it becomes clear they don't apply to scenarios other than those in which they were formed.

So yes, count on that stuff that Archimedes earned his reputation for. And the supporting real world experiences. As for the misconceptions, don't stake your life on it without further investigation. Doing so may just kill you and yours.
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Old 13-10-2007, 18:16   #93
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Keegan, I don't sell chain or rode. (GMac does). Go figure.

If you want to use a kellet, or not, it is of absolutely no impact to me or Rocna. If the belief of security lets you sleep at night, good for you. It certainly won't hurt. These pages I link to are quick versions of articles I want to get published for a buck or two at some point, really it isn't related to the anchors.
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Old 13-10-2007, 18:23   #94
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Keegan, I don't sell chain or rode. (GMac does). Go figure.

If you want to use a kellet, or not, it is of absolutely no impact to me or Rocna. If the belief of security lets you sleep at night, good for you. It certainly won't hurt. These pages I link to are quick versions of articles I want to get published for a buck or two at some point, really it isn't related to the anchors.
I am just kidding with you, I like your product and enjoy reading yours and others posts on anchors, rode and chain.

Cheers,

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Old 13-10-2007, 18:41   #95
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It's not possible to take into account every different factor. Our chart is based on mono-hull LOAs but you can basically just go one size larger for multi-hulls. The difference is sort of constant.
Why would you need to go larger for a lighter boat?

Windage?
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Old 13-10-2007, 19:08   #96
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Craig, I'm not having a go so calm down. Just saying there is a mass of 'numbers' here which you are using to support more a rope only rode than a chain or a mix. That is fine as long as everyone watching is aware that the discussion is calculator based not what actually happens in 95% of real life. Yes Alain, Peter and Steve are people who should be listened too, along with many others. Mind you 2 of them also have a vested interest in expounding certain points over others due to anchor maker connections but are still well worth listening too. (to or too there?, I can never work that out)

As you brought those 3 notable people up can you inform us of which, if any have all rope rodes? I know for a fact 2 have all chain and I'm pretty sure the 3rd has as well. As I pointed out theory points to all rope rodes but practice by your 3 notables does not.

Another point - It very well proven that if someone is having slippery anchor issues increasing chain length can often stop that. Not always but mostly. Again theory and practice don't meet at the same place.

Again I will ask you don't use Steve as an anchoring example. Steve anchor is massive even by his own well declared 'I love massive' desires. Your continual use of Steve and his Rocna does in no way mean the rocna is better than anything else and is quite counter productive to any good anchoring discussion by and aimed at the average yachie. I'd confidently say any anchor of 115kg would hold Steves boat just as well 90% of the time. If you want a good example please use Peter as his gear is a lot more sized in what is common place. I'm sure your arguments would stack up just the same and coming from a lot more realistic base would be more believable.

Keegan - yes Craig does have a very vested interest in the fortunes of the Rocna anchor so as anyone would expect there will be a slight slant on things. To expect otherwise would be foolish. But that doesn't mean Craig does not have some good knowledge to impart to many and listening to him may just mean you learn a bit of something you haven't before. This is a good thing.

Regarding his link to his Anchoring, catenery commentary, I've read it and all I'd like to say is

Quote:
Both those articles are misleading, although not necessarily "wrong"
but in a singular way. Actually there is the odd thing that is just wrong but nothing huge.

Re: Kellets, They can be useful for those who haven't set their rode up properly in the first place. There are many who will swear they work and work well. Whether they do or don't, I don't really care as my anchoring system was well thought out before purchase so I have no need for one. I have a rope chain mix. Saying that I have recently borrowed an Anchor Buddy so I can try it on my boat out of interest sake.

This is the same boat we have been using to test anchors and anchoring systems on. Quite interesting to see the data building when you have a fixed boat and user doing the exact same thing in 6 differing spots (bottom types, etc) over a long period of time with differing gear. We have also tried to duplicate some of the theory and have found it just can't be done or is based on wrong starting assumption, loads applied being a biggy. Some has stacked up well though.

For those who don't know, I do sell chain, rope and anchors (inc the Rocna) and specify anchoring systems as a job. I'm just here as I'm the poor prick who has to deal with the punter that comes in with weird and wonderful ideas he has read on the net or heard from a mate. Often those ideas means he will spend twice what he needs to or wants a miss-matched system, which when push comes to shove will let him down.

Now leave me alone, I'm trying to finish my new pricelist and the bloody sun has just come out, damn
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Old 13-10-2007, 19:17   #97
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Quote:
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This is the same boat we have been using to test anchors and anchoring systems on. Quite interesting to see the data building when you have a fixed boat and user doing the exact same thing in 6 differing spots (bottom types, etc) over a long period of time with differing gear. We have also tried to duplicate some of the theory and have found it just can't be done or is based on wrong starting assumption, loads applied being a biggy. Some has stacked up well though.

Gmac:

You always seem to hit the nail on the head with your replys.

If you could only choose one anchor to take with you on an around the world voyage which one would it be?

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Old 13-10-2007, 19:58   #98
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Pricelists are boring so you're lucky

Firstly I must say what is best for me may not be best for the bloke on the boat next too me, even if they are the same boat. I'm a very strong believer in 'horses for courses'.

For ME -
If money no object - a alloy spade. This is probably due to my strong racing background in which weight is pure evil. I don't have any major issues with their strength by the way or setting characteristics. Both could be a tad better but I think they are close as now.
For pure strength and taking alloy anchors out of the question and money still no object - a Rocna over a steel Spade.
If money was an BIG issue as it is with many - A Manson Supreme followed by Rocna then Spade.
If money not a BIG issue and no alloys - Rocna.

Damn, hate it when you push the wrong button.

Saying all of that I currently have 2 alloy Spades aboard and have had for the last 5 months, a Rocna previously for 6 months. Next weekend 1 Spade off and a Supreme on. As I mentioned before this is just part of our ongoing field testing.

I think all 3 are well above 95% of the rest and each has their place in the big scheme. I do think Spade and Rocna will out hold a Supreme by a bit but not much, certainly all 3's holding loads are right up there in the place you don't want to find out. I do think Spade has a big price issue but then it is the most labour intensive so that is understandable. Rocna is certainly the one that would tear apart last and one very strongly build puppy. The Supreme while not being 'quite' up with those 2 in performance is close to being the best bang for the average guys buck.

I don't have major issues with many other anchors and see no reason for many to change 'just for the sake of changing' though. The Delta is good as is the CQR, Bruce and so on but they all suffer from annoying issues the above 3 have managed to mostly design out i.e setting being the biggy.

So that is what I would recommend for ME. For you it could be quite different but it would probably be one of the 1st 3 I'd say these days.

All anchor recommendations are assuming a matching rode. Sizing again will vary with type of use, expected destination, user experience and nervousness.

Before anyone pops in with knock-off comments may I add it is very very common for a certain NZ made anchor not called a Supreme to be spoken about as a knock-off of a Sarca. While this is wildly un-true or even close to being reality it does show what is often in the eye of the beholder may not necessarily be the truth.
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Old 13-10-2007, 20:37   #99
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As you brought those 3 notable people up can you inform us of which, if any have all rope rodes? I know for a fact 2 have all chain and I'm pretty sure the 3rd has as well. As I pointed out theory points to all rope rodes but practice by your 3 notables does not.
All three use rope when required.

Dashew has done extensive research and written a number of articles on the specific topic of rope rode. Alain insists the Spade requires an adequate stretch of rope in the rode, and Peter always uses a snubber in bad conditions even on a boat the size of his. The particulars tend to depend on the boat size and are completely commensurate with any of my "theory".

All three have individually far greater experience than you, and combined in agreement I know whom I'd listen to - forgetting the theory.

Quote:
Originally Posted by GMac View Post
Again theory and practice don't meet at the same place.
Yes, they do. Maybe you don't understand this terrible thing "theory" or how to apply it properly.

The point of all these discussions isn't to predict some behavior, or somehow change reality. My objective at least is to simply explain why things work like they do, and help people understand this so they may make sensible decisions with regard to their own equipment.

Quote:
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Mind you 2 of them also have a vested interest in expounding certain points over others due to anchor maker connections but are still well worth listening too.
What points? Actually it would be much easier to just go with the flow and not waste energy fighting the traditional mindset. Why should we care if people want to use 12mm chain and a 15Kg kellet with a Rocna 20? Let them... Poiraud for his part tends to parrot Fraysse, I haven't seen much original work from him. He insists on rope to the extent that the Spade warranty has an "out" in it should their recommendations not be followed... but only because there is good reason for it.

Hence I am not afraid too argue this issue, because I can be neutral.

Quote:
Originally Posted by GMac View Post
Again I will ask you don't use Steve as an anchoring example. Steve anchor is massive even by his own well declared 'I love massive' desires. Your continual use of Steve and his Rocna does in no way mean the rocna is better than anything else and is quite counter productive to any good anchoring discussion by and aimed at the average yachie. I'd confidently say any anchor of 115kg would hold Steves boat just as well 90% of the time. If you want a good example please use Peter as his gear is a lot more sized in what is common place. I'm sure your arguments would stack up just the same and coming from a lot more realistic base would be more believable.
I did not refer to Dashew's anchor in this recent discussion, only his (entirely correct) approach to rode make-up.

In any case Dashew disagrees with you and I suggest he is in the better position to make that call.

His philosophy, based both on theory and his own extensive experience, makes an eminent amount of sense for small boats and I will continue to endorse it.

Quote:
Originally Posted by GMac View Post
Regarding [Craig's] link to his Anchoring, catenery commentary, I've read it and all I'd like to say is

but in a singular way. Actually there is the odd thing that is just wrong but nothing huge.
Perhaps you do not understand the conclusions.

Quote:
Originally Posted by GMac View Post
Re: Kellets, They can be useful for those who haven't set their rode up properly in the first place. There are many who will swear they work and work well. Whether they do or don't, I don't really care as my anchoring system was well thought out before purchase so I have no need for one.
Indeed, no need for one, and it will do nothing to improve the performance of the anchor assuming your rode is well designed in the first place. No one is saying they "don't work", of course they work to some degree. That degree will even be significant IF:
1) the anchor is too small or a poor type, and
2) not enough scope is being used, and
3) the holding is less than good.
(So, you'll drag in 30 knots instead of 25.)
But from the big picture perspective, considering the optimum choice of rode components and sensible deployment, they have no place and the resources are better invested elsewhere if higher performance is being chased.
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Old 13-10-2007, 20:44   #100
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Why would you need to go larger for a lighter boat?

Windage?
Of course, multihulls have a much larger windage profile than comparable multihulls of the same LOA.

The boat is not "lighter" because you are selecting the displacement on the chart... so you just choose the right range in the first place.
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Old 13-10-2007, 21:56   #101
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All 3 being so experienced would know the value of a damn good snubber as anyone one would expect BUT their primary rodes are all chain not rope. If the all rope theory is so sound why don't those 3 have that?

Combined on the water experience, absolutely, all 3 are well older than me to start with. Combined experience dealing with the large range of boats I deal with each week use by many assorted skill levels in many varying situations, maybe or maybe not, I don't know.

In your theory all rope is best, on the water practice has found that not to be the case. That's the theory verse practice I'm talking about.

Yes you can be neutral from time to time. Getting better of late by the way

I have absolutely no issue with Steves gear and actually encourage people to have an anchoring system that makes them 'feel good'. If it takes bloody massive for Steve to feel good I'm all for it and good on him for fitting gear that does. I personally run lighter gear than I would suggest for most of my punters and I sleep very well. It still doesn't mean that either Steve or I are a good examples of an average boater, both of us are not. Hence when I mention the size of my gear I qualify it by saying it is lighter than I would recommend and don't use it as a un-qualified shining example of how good the gear is as a marketing thing.

As a matter of fact you don't always endorse Steves conclusions. We have more than a few people in who you have speced an anchor for and the sizing is more often than not quite reasonable, you're one of the best out there usually. If you followed Steves theory we would be getting people asking for 15kg anchor to put on their 7mt fizz nasty. As I say often, Rocna has arguably the best sizing chart in the game. It certainly doesn't follow Steve's ratios.

Your commentary does have some very good and valid points but it also has some flaws, not biggys but they are there. There is also one or 2 bits that are wrong but in the context you have them it doesn't really matter to the end conclusion. Don't panic as you can rip into 99% of anchor articles in one way or another if you really wanted too, just like anchor tests. A bit like a recent one I read that had rocna, cqr's and sarcas and pretty much the same thing, that's not right either is it? We have already had 2 punters in with that artical in hand saying "Mr XXXX says they work the same so why pay more for a Rocna?" Again, dumbarses believing everything that is written. Sure they were not cruisers (usually more experienced and knowledgeable than weekend warriors) though but we have had questions raised over points I know they have read on forums like this, possibly even this one.

re the kellets again, I do agree with you but to not quite the extreme you go to. There is a place for them and they do add rather than detract so one could argue lots of 'little goods' do help the big picture when all added up.
Again they are another 'feel good' enhancing tool and at the end of the day feeling good about your anchor system choice, even if not the ideal choice, is one of the biggest things about anchoring.

8mt boat with 100mts of 10mm chain and a 33kg Rocna - if the punter is not happy with that they will not sleep well so it makes it a bad choice even though it is another massive overkill. I'm assuming the boat will still float in this example obviously

Anchoring is an incredibly grey art. There is no one right way, bit of equipment, method of use or anything like that. So anything said must be put in context and/or qualified just in case a dumbarse reads it then kills himself and his family. And we are back to where and why I started my 1st post.

Now back to that bloody pricelist
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Old 14-10-2007, 04:15   #102
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Thanks craigsmith & others for assisting this ignorant dumbbell towards an understanding of the theory explaining anchor rode behavior.

Obviously, being based upon a false supposition (lever principle), my original hypothesis was inaccurate.

Quote:
Originally Posted by GordMay
”... In principle, I see an anchor assembly as a class 2 lever (*2) , wherein the anchor shackle represents the fulcrum, the boat is the point effort (dumbbell arm), and the rode & kellet represent the load (resistance arm) ...
... Are we talking about “torque”, (being the product of the distance of the applied force from the axis of rotation and the component of the applied force that is perpendicular to the lever arm) ...”


Quote:
Originally Posted by craigsmith
”... No, there is no lever arm because the rode is not rigid. There is no "torque"...”
Pithy quotations can sometimes be extremely effective at capturing and concisely communicating thoughts and ideas. However, like explanatory theories, they must be based upon true suppositions.

In the case of Jan L. A. van de Snepscheut’s* remark that: "In theory there is no difference between theory and practice. In practice there is." (or “The difference between theory and practice in theory is much less than the difference between theory and practice in practice.” ~ Randal L Schwartz) the essential error(s) lies in an erroneous definition of scientific or engineering theory.

* Often attributed to Yogi Berra

Theory explains practice:
In science and engineering, a theory is a mathematical or logical explanation of observable (& verifiable) phenomena (practice).
Hence, a scientific theory is not an unsubstantiated hypothesis, as is sometimes misunderstood in common usage.
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Old 14-10-2007, 08:11   #103
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Of course, multihulls have a much larger windage profile than comparable multihulls of the same LOA.

The boat is not "lighter" because you are selecting the displacement on the chart... so you just choose the right range in the first place.
OK, got it.

For a Gemini I would pick a 10 Kg. model.
(I live in Florida and would find a nice little spot to leave it in a hurricane - go up one size??)
I still want 100 ft of chain.
But that does not mean that 60ft would be just fine.
I would need advice.

I have another question too. Silly I know but I need my hand held.

I will make up a bridle - I think 30 ft for each leg.
Sound OK?

The question;

After I pay out all the chain and get into rope rode, how do I attach the bridle to the rode?
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Old 14-10-2007, 09:36   #104
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Rolling hitch or equivalent. There is a discussion of attaching a snubber, which is basically the same problem in:

http://www.cruisersforum.com/forums/...bber-7800.html

Mark.
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Old 14-10-2007, 10:54   #105
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Rolling hitch or equivalent. There is a discussion of attaching a snubber, which is basically the same problem in:

http://www.cruisersforum.com/forums/...bber-7800.html

Mark.
I am obviously missing something.

This is in the post describing exactly what to do.


For a bridle you can make a single loop from say a port cleat outboard and across the bow to the stbd cleat (the whole thing can be Dacron) and use a Prusic hitch from the center of the loop to the rode. You can middle a length of snubber and attach it at the middling point to the bridle center and lead both ends to the rode if you want. It will work fine.

In my mind, the bridle would have to be put on the rode with this knot and then the bitter ends fed outboard and back to the cleats on each hull. I don't get it.
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