Noelex
Veteran Member
I am not sure what is "suspect". Ignoring my previous sailing experience I have been full time cruising, staying at anchor for over 300 days a year for the last 8 years. I have owned a Fortress anchor for all of this time.
Another round of anchor controversy
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I am not sure what is "suspect". Ignoring my previous sailing experience I have been full time cruising, staying at anchor for over 300 days a year for the last 8 years. I have owned a Fortress anchor for all of this time.
psneeld
Guru
just another case of believing or using data that is out to lunch at least 50% of the time....psneeld,
I had always assumed that the ABYC were 'worst case', so your example of the tensions developed in a tidal creek are completely correct, but that same anchor will be required for that 'worst case' in an open roadstead with 15knts with a bit of surge, wind over tide and some veering. At 15 knots the tension is not even enough to lift all the chain, say 100', off the seabed.
I always assume anchors are chosen for worst case (and may we all be restricted to 15knots of wind in 2015!) but actually have anchors for 50 knots
I'm with Marin sorting through personal experience is no more full of landmines than technical or "test" data and has gotten quite a few experienced boaters where they want to be with anchors. Especially when my own personal experiences reinforce what others say and is in opposition to what I read from "testing".
Noelex,
I quote what you said - you imply anchor(s) plural, you also imply Danforth (which you do not own and thus must be on other vessels). You now suggest you have been using your own Fortress in changes of tide - etc - why when you know, or say you know, it is so dangerous do you ever use your Fortress - except for a guaranteed straight line pull?
The gist of your post (and the implication to me) was that you had broadly viewed many Fortress and many Danforths, specifically these brands You now suggest its only your Fortress? and maybe no Danforths. Without more evidence you seem to be trolling.
I'm guessing you are struggling to find any images of a Fortress or genuine Danforth as not seen much in the Med or even Asia (as Japanese cruisers are notable by their absence). Its that jingoistic buying pattern. However Brittany anchors are very common in the Med - and you almost never mention them at all. So anchors that are common you ignore and anchors that are like hens teeth you make a point of mentioning.
Delfin
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+1. Thank you for noticing.
Noelex
Veteran Member
Brian I know we disagree about the about the ability of the Fortress anchor to reliably cope with significant change in direction of pull. On this subject I think we are better to agree to disagree, and perhaps open another bottle of champagne to celebrate the new year
.As to the maths I don't see anything wrong with your calculations:
"one single 40-ft boat will encounter loads of 300 lbs in 15 knots of wind, as per ABYC tables"
My tables give 288 Lbs which is close enough.
I don't see how that disagrees with my figures:
Re-reading River Cruisers post he probably is referring to 5 not 4 boats (his boat plus four others) rafted up together in which case it would be equivalent to 29 not 26 knots. The total drag would not necessarily be the sum of the drag on 5 individual boats, but it would be close.
Perhaps you could explain how my maths is flawed? I am happy to learn if there is a mistake.
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Noelex
Veteran Member
Jonathan, I find it surprising, and perhaps strangely reassuring
that anyone would suggest that I have not spent enough time studying anchors, particularly over the last 8 years.In the last week I have posted 14 photos of the performance of a Guardian anchor. (a slightly simplified Fortress made by the same company)
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Anchor Brian
Senior Member
Noelex, do you think that 5 boats tied together, each of separate displacement and windage, will have the same load in 15 knots of wind as does one single boat of a comparable length in 30 knots of wind?
Djbangi, I saw the images that Noelex posted on the Cruisers Forum of the tiny 2.5 lb / 1 kg Guardian G-5 for boats up to 16-ft, and I am wondering if he will use this anchor for his basis of evidence regarding the performance of our product.....and compare it to the over-sized 125 lb / 55 kg Mantus, which he glowingly posts images of in that thread.
This anchor also has a shank that bent under a minimal load while in use aboard his 45+ (?) boat.
Djbangi, I saw the images that Noelex posted on the Cruisers Forum of the tiny 2.5 lb / 1 kg Guardian G-5 for boats up to 16-ft, and I am wondering if he will use this anchor for his basis of evidence regarding the performance of our product.....and compare it to the over-sized 125 lb / 55 kg Mantus, which he glowingly posts images of in that thread.
This anchor also has a shank that bent under a minimal load while in use aboard his 45+ (?) boat.
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Jonathan, I find it surprising, and perhaps strangely reassuring
In the last week I have posted 14 photos of the performance of a Guardian anchor. (a slightly simplified Fortress made by the same company)[/QUOTE
I cannot think you are serious:
If your posts of your 'tests' of a Guardian anchor are meant to lift your credibility I suspect you will be most disappointing. There will be some sycophants around but most will simply find your evidence a joke - but maybe that was the intention and the humorous punch line will come later.
You have made a public statement saying you have observed Fortress/Danforth anchors in use- I am still waiting for you to substantiate that statement as you have used that statement as the basis of a derogatory comment of both Danforth and Fortress. I think either you show statistically sound evidence on which you base your accusations or simply apologise.
If I want to pass comment on the negative performance of a product I would be very, very careful and have some form of corroboratory information - otherwise its trolling.
Noelex,
You establish yourself as an expert in anchor performance, your previous post, and with that you also take on a mantle of responsibility which in your case is further also underpinned by being a Moderator on Cruisers Forum.
Given the foregoing I think you, and CF, appear to be walking on very thin ice as there is no evidence you have to support your contention that you have observed a Fortress or Danforth 'performing' in a way that is dangerous. You 'underpin' some of your comments by a childish series of images of a 1.5kg Guardian being 'tested' in 1m of water. You have also, on CF, made unsubstantiated negative comments of other anchors, in particular convex anchors (some of which you have never seen in use nor used yourself).
Your criticisms of Fortress, Danforth and convex anchors has been sustained and repetitive and until you mentioned you actually had seen this 'poor' performance of both genuine Danforth and Fortress your comments could have been anecdotal (and not that of an expert). Now as an expert of 8 years, who states publicly to have seen this poor performance, you need to be able to substantiate your comments. Over 8 years you would need to be able to document the number of times you have seen this and define for each example where, which vessels, depth, scope, wind speed etc etc. These are serious accusation it needs serious documentation.
In the absence of proof I would have thought that the possibility of legal action starts to loom, for you personally and CF.
You establish yourself as an expert in anchor performance, your previous post, and with that you also take on a mantle of responsibility which in your case is further also underpinned by being a Moderator on Cruisers Forum.
Given the foregoing I think you, and CF, appear to be walking on very thin ice as there is no evidence you have to support your contention that you have observed a Fortress or Danforth 'performing' in a way that is dangerous. You 'underpin' some of your comments by a childish series of images of a 1.5kg Guardian being 'tested' in 1m of water. You have also, on CF, made unsubstantiated negative comments of other anchors, in particular convex anchors (some of which you have never seen in use nor used yourself).
Your criticisms of Fortress, Danforth and convex anchors has been sustained and repetitive and until you mentioned you actually had seen this 'poor' performance of both genuine Danforth and Fortress your comments could have been anecdotal (and not that of an expert). Now as an expert of 8 years, who states publicly to have seen this poor performance, you need to be able to substantiate your comments. Over 8 years you would need to be able to document the number of times you have seen this and define for each example where, which vessels, depth, scope, wind speed etc etc. These are serious accusation it needs serious documentation.
In the absence of proof I would have thought that the possibility of legal action starts to loom, for you personally and CF.
Noelex
Veteran Member
River Cruiser referred to 15mph not 15 knots. 15mph = 13 knots
ABYC figures for the force on the anchor rode of a single 38 foot boat are:
13 knots= 198 lb
30 knots = 1,056 lb
An alternative formula has been proposed by Professor Knox for calculating anchor forces. His formula gives lower numbers, but the ratio with increasing windspeed is the same. The following results for a single 38 foot boat:
13 knots= 45 Kgf
30 knots = 241 Kgf
It cannot be assumed that 5 boats tied together will experience 5x the load of a single boat, but as an approximation it will be reasonably close. 5x198 lb = 990 lb. this is the force produced by a single 38 foot boat at 29 knots. Professor Knox's formula gives exactly the same windspeed.
As the force rises dramatically with windspeed, errors in this assumption are not great in any case. For example if we assume 5 boats tied together will experience 7x the load of single boat then the equivalent windspeed only rises slightly to 34 knots.
Anchor forces rise roughly as the square of the windspeed so the force rises much more dramatically with an increase in windspeed than might be imagined.
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FF
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>Anchor forces rise roughly as the square of the wind speed so the force rises much more dramatically with an increase in wind speed than might be imagined <
Which is why thunder storms are so much fun!
13 knots= 45 Kgf
30 knots = 241 Kgf
Fun begins in the puffs,, which frequently will be 25%-50% higher than the constant wind speed.
50 mph in the thunderstorm = 60- 75 in the puffs and the anchor mfg.recommended watch fob begins to look rather small.
Which is why thunder storms are so much fun!
13 knots= 45 Kgf
30 knots = 241 Kgf
Fun begins in the puffs,, which frequently will be 25%-50% higher than the constant wind speed.
50 mph in the thunderstorm = 60- 75 in the puffs and the anchor mfg.recommended watch fob begins to look rather small.
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ranger58sb
Guru
Djbangi asked about the SuperMax earlier, and I see that's included in the Sailing Foundation tests... identified as MAX 17, which IIRC is the non-pivoting version.
I can't interpret the charts exactly without the key to asterisk and footnotes, but it looks like it did well enough (in some chart columns) -- when set properly. Second only to the FX-37, I think?
I think the instructions for setting the non-pivoting SuperMax are different from what ours are (i.e., for the pivoting model). Can't remember details...
-Chris
ranger58sb
Guru
I think I'd have been inclined to interpret this as probably an anchor which has not yet been properly set. And I'd have suspected whatever poor technique caused that condition could have been applied to any anchor style.
Maybe the skipper(s) just threw it (them) overboard, opened a beverage, and went swimming?
-Chris
sunchaser
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All too much focusing on wind and pseudo mathematics. Some of us could baffle this subject even more by bringing up rope/chain selection, wind, wave and current force determination using differential equations.
But back to reality. Add a few big waves tugging viciously on the anchor and you really begin to understand the entire subject is as much an art as science. Almost a full century of Danforth style anchors successfully being used in all sorts of bottoms is more than anecdotal. It is just common sense to use one as either a primary or better yet a backup with the more easily stowed and "good enough" newer designs ever so frequently used as primary.
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eyschulman
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Way back at post #1 I stated this particular thread but had little to do with starting the long running controversy regarding anchors and ground tackle. Some things I take away from the thread and controversy in general mostly recurrent old hat stuff are: #1 many people get passionate about anchors. #2 Those who sell products, anchors included, will defend their product and endeavor to advertise it. #3 There is a lot about the art and science of anchoring that is known and still unknown. #4 Tests preformed in labs and in the field do not always reflect accurately on how things play out in the real world There are often too many variables to account for particularly when humans are involved in the formulas. Regarding the small piece of the overall anchoring and ground tackle universe the Fortress test or soft mud test sponsored by Fortress reinforces the fairly well known ability of Danforth anchors to run up high holding power readings in mud substrates. The finding that several well thought of types of anchors did not do as well raised interest and questions as to why. This finding seems to disagree with the experience of many boaters and the question raised is why? The answers may or may not be something that can be demonstrated with further testing but it probably should be done. Since there does not appear to be a significant feed back from the general anchoring public about the poor testing anchors causing problems there may be something else going on here. The test results could be either floored or the parameters insignificant as compared to how and where people anchor. The test in question even with its very narrow field of view does give us information, but the big issue is how do we interpret and apply that information. For example if a tire company demonstrates that its product grips better in snow than others and some highly touted tires do not do so well what is the overall significance? Does the good gripping tie do well on dry road does it make noise does it stop well does it wear well does it handle high speed etc. etc. etc. Are people going to be happy with that tire for general use? If all the tires in the test were submitted to the many other conditions how would the supper snow tire fare? Which of all the tires would be the best compromise? Yes we can change anchors for different substrates and some do,but that can get old for the typical cruiser who I believe would like the best all around unit for the bow pulpit. As I pointed out before this is at least a 15 round bout and we are only in the early rounds.
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CPseudonym
Moderator Emeritus
I'm by no means anchoring in your conditions Tom, nevertheless I'm impressed by how my woefully undersized genuine Danforth holds in some really fluffy muck.
eyschulman
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OR, maybe folks dont like hearing that their baby might be ugly. Even if it is a highly polished ULTRA.
Not that I am here to sell Ultras but did they not test fairly well in the Fortress test? The shine and sleek shape I find seems to have an added benefit in mud. I have the impression that the anchor comes up cleaner and washes of easier than some other anchors I have owned, but all this is outside of the target range which is the Fortress test and how it relates to the questions raised regarding the other than Fortress anchors. If my whole post is contemplated rather than part out of context the need for ultra bashing disappears.
Anchor Brian
Senior Member
Eyschulman,
FWIW, I thought that post #226 was an excellent analogy.
Happy New Year,
Brian
FWIW, I thought that post #226 was an excellent analogy.
Happy New Year,
Brian
Nomad Willy
Guru
I think eyschulman left out the most important part.
The test exposed a clear weakness in the very popular Rocna that many thought was a flawless product that could do no wrong. There's no such anchor. There never will be and the over the top enthusiasm for the Rocna is now in much more realistic focus.
The test exposed a clear weakness in the very popular Rocna that many thought was a flawless product that could do no wrong. There's no such anchor. There never will be and the over the top enthusiasm for the Rocna is now in much more realistic focus.
healhustler
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I knew eventually I'd get some real value out of this discussion. Up to now, I couldn't substantiate SS anchors to the Admiral. Thanks eyeschulman!
dwhatty
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Right on! We bought a RockStarNa last year, so it's obviously the best.
(But..., er, just in case it isn't, though we are never (well, almost never) wrong, we keep an FX 23 on a second rode in the laz ready to deploy and the knock off Bruce that came with the boat in the garage ready to deploy to hold down said garage in a windstorm. True fact that.)
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Nomad Willy
Guru
David re the Bruce I've been thinking about wind protection for my newest carport. The rods meant to hold it down largely went into loose ground.
We have an FX23 on the swimstep to use as a stern anchor, or as the main anchor should we encounter conditions that our primary anchor won't handle. So far, we've only needed the Fortress as a stern anchor. Our primary anchor has to date handled all the bottom conditions it's encountered, including holding two boats in mushy mud, albeit under fairly non-stressful conditions. But knowing the Danforth design's excellent performance in mud and sand, we thought it would be wise to have such an anchor design on board.
And we can attest to the superiority of the Bruce anchor as a garage stabilization component. In our case, it propped open a door, but had we experienced a high wind situation I'm sure that, buried deeply in the garden, it would have done an equally superb job of assisting in keeping the garage intact
I'm wondering if Bruce & Co. missed the marketing train with this anchor. Instead of pawning if off on unsuspecting boaters, perhaps they should have targeted the home construction industry. For example, would surrounding a house with buried Bruce anchors cross-connected to the foundation meet the building code requirements for structural stability in an earthquake area like Puget Sound?
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Delfin
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LOL, you are completely relentless...
sunchaser
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So I have a Bruce and a Fortress. So anchor #2 by popular acclaim is taken care of. What anchor would I best be advised to purchase in the 85# area that would replace my (never drags & always sets) foundation ready Bruce and fits in the same length anchor "bed"?
I can't take this abuse anymore!
I can't take this abuse anymore!
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Since your 85# Bruce weighs 85 pounds, my guess is that it's up in the weight range where this design tends to work. And since your Bruce has so far never let you down, then it would make absolutely no sense to replace it. Had our much lighter Bruce never let us down, it would still be on the pulpit.
However..... you do have to deal with the issue of your anchor being of the "old generation" of designs and is therefore sort of like wearing a 1970's pastel leisure suit. So what I would suggest is that you have someone fabricate a "rollbar suit," something made of some lightweight, weatherproof material that can be clipped around your Bruce to make it appear, at least from 15 or 20 feet away, to be a new-generation rollbar anchor. This "anchor shroud," we'll call it, could even be chrome-plated to bring it in line with the current trend in polished bow bling.
So while underway or in a harbor, everyone will assume you are up to speed with the most current trend in ground tackle. Then, when you actually need to use your anchor, it's a simple matter of removing and stowing the anchor shroud and using your Bruce in the manner to which you are accustomed.
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As Noelex was unable to provide the formula this is a formula that John Knox used in one of his articles, 2002, and he cross referenced it to articles in YM 1099 and PBO 386 (which he might have written - but the formula could have been developed by A N Other).
Peak cable Tension in Kg
= (1/500) x (LOA metres - squared) x (wind speed knots squared)
The formula is contingent on the idea that wind resistance of a vessel is proportional to its frontal area and this roughly proportional to LOA squared. This might or might not be true of a yacht (modern yachts seem to have much higher windage than those of the 1990s) but I suspect not true of a trawler.
The formula completely falls apart if you try to apply it to 4 or 5 vessels rafted up.
Peak cable Tension in Kg
= (1/500) x (LOA metres - squared) x (wind speed knots squared)
The formula is contingent on the idea that wind resistance of a vessel is proportional to its frontal area and this roughly proportional to LOA squared. This might or might not be true of a yacht (modern yachts seem to have much higher windage than those of the 1990s) but I suspect not true of a trawler.
The formula completely falls apart if you try to apply it to 4 or 5 vessels rafted up.
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