Chesapeake Anchor Holding Power Test

[Nomad Willy]

We talk so much about anchors and anchoring (and I'm sure boaters elsewhere do also) most boaters probably (and rightfully so) think how well an anchor is going to work wherever it is dropped is very questionable. So when in doubt (and size matters) get a bigger anchor.

I don't know about elsewhere but here using a small anchor would seem foolhardy and no one wants to appear to be a fool so even socially using a bigger anchor is the better of choices.

What are the effects of doubling;
A. the physical size of an anchor
and
B. the weight of an anchor.

The size of an anchor and the weight are interrelated as even the Fortress wouldn't work if it weighed nothing.

But the interesting part since Djbangi's post is will an anchor more than double it's holding power by doubling it's size? I feel that may help to explain why bigger boats and especially ships seem to have such small anchors. Or is it that smaller boats have overly large anchors? I think the latter is definitely the case but to what degree?

Djbangi what a very interesting post.

 

[Delfin]

What is interesting about the data is that if you were in the Chesapeake, or somewhere with a similar seabed, then for many of the anchors you would soon find they simply did not work - no matter how many times you tried them. It would be obvious that if you wanted to overnight you would need to move to another location with a different seabed (or change your anchor). But some of the anchors do appear to develop hold and it would not be unusual for many to think they were safe for whatever weather came their way that night. This in fact is incorrect as the ABYC data correlated with the graphs clearly demonstrates that the hold is illusory - if not downright misleadingly dangerous.

Nearly all anchor testing is conducted in hard seabeds, and harder and harder seabeds seem to be used. Even today people are hammering the superiority of specific designs by evidence in one seabed alone (- good marketing, but honest?) Obviously not everyone anchors in soft mud (not for that matter in rock hard sand) - but there must be a point - in seabed softness - where this demonstrated superiority of the Fortress at 45 degrees loses its impact (and the 32 degree fluke angle become appropriate). One has to wonder where that crossover point might be - might it be somewhere in 'soft sand' and that some of these anchors (tested by Fortress) might be similarly lacking in performance in good clean soft sand.

Great post, thank you.

Seems to me that anchor tests have general utility in that they compare the performance of difference designs under a set of circumstances. Brian's test attempted to multiply those sets with different locations but each location was nevertheless likely pretty similar. Within the boundaries of those limitations, it is clear that a Fortress set to 45 degrees is one heck of an anchor, which is why if someone asks my opinion I will always advise having one on board.

The problem with tests is that the question of which anchor is best is pretty much a "how long is a piece of string" type question. One is left with hoping to get a hook that may not be the best in all categories, but is generally good enough in the categories of bottom types, current and wind conditions generally experienced.

Add to that the simple physics of mass and it gets even more complicated. All things being equal, I would prefer to be anchored to a 250# Forfjord than a 100# whatever else you got. And the performance of an anchor isn't likely to be linear - that is, as you increase its mass its performance relative to other hooks may change. You can see this in the test that Evans Starzinger did in Patagonia with a large Manson, Rocna and Ray (a.k.a. Bruce). No one would think that a 45# Claw/Bruce/Ray would perform better than a 45# Manson, but in the conditions tested and the mass tested in this case, it did. Delfin's 176# Claw held her first time every time in some pretty good winds and so does the Ultra we have now. The only difference between the two is that the Ultra definitely is harder to retrieve, which I have to assume means it has better hold than the Claw - again, at least in the conditions I've used it.

Because of the nearly infinite variables of bottom type, performance under available scope, initial performance under steady load in a test vs. performance when the little tugs experienced in the real world set the hook, mass, and likely as important as any variable - the skill of the user - and you have fodder for endless disputes on which is the "best" anchor.

So, in that spirit, why the heck would anyone buy a Rocna when a perfectly good and clearly superior Manson Supreme is available???

 

[Anchor Brian]

The Delta and the CQR were weak at the end of the pull and I wonder if scope had anything to do with it.

Eric, Bob Taylor (US Navy guy) reviewed the results and he has a formula that calculates the pull angle as it relates to the anchor rode used and the holding power the anchor achieved, and he determined that the pull angle from the decreasing scope was very minimal, particularly for the anchors that did not bury deeply and generate much resistance.

He sent me a detailed write up about this with some charts, and if I can ever figure it out and fully understand it, then I will post the information.

Were you able to test any of the armoury of anchors you had at your disposal in smaller, or larger sizes?

Rather than buying one bigger anchor (than recommended by anchor makers) one might conclude carrying more than one anchor, of different designs, might be prudent?

Djbangi, during preliminary tests we tested a 32 lb FX-55, and for both preliminary and public tests, the 10 lb FX-16.

The FX-55 @ the 45° angle hit peaks of over 4,000 lbs during two tests and tripped the winch both times in the process, and the FX-16 averaged peaks of about 1,500 lbs during several pulls.

On the last day of public testing, the FX-16 took about 20 minutes to break out of the bottom after held to 1,600 lbs, and it came up with a granular type of mud, indicating that it was buried beneath the soft mud and oyster shells that we had seen previously, which was compacted on the better performing anchors.

I certainly think that carrying more than one anchor type is prudent, and that a Danforth-type should be part of the arsenal.

Brian

 

[Moonstruck]

One of the enjoyable things about anchoring in the Chesapeake is that most of the anchorages allow snuggling up near a windward shore. The large trees in most areas will give good protection. Of course, the varying winds of a thunderstorm pose a different approach, but most of the anchorages we use are quiet and protected. The Danforth and Delta have both worked well. The Danforth is much harder to clean the mud.

 

[ranger58sb]

Brian, is there a way you can characterize the difference in size between a 21-lb FX-37 and the similar 35-lb Danforth HT in this test? Maybe a "square inches of surface" or some such?

And then what would be the size difference of the FX-55 compared to those, and maybe compared to the next similar size Danforth HT?

I've always assumed -- once reaching a certain minimum weight, below which anchors may tend to "sail" through the water or "skate" along the bottom -- that size matters perhaps even more than additional weight.

?

I've always been pleased with our FX-37's performance here in the Chesapeake, and haven't even ever used the 45° angle yet!

-Chris

 

[Anchor Brian]

Brian, is there a way you can characterize the difference in size between a 21-lb FX-37 and the similar 35-lb Danforth HT in this test? Maybe a "square inches of surface" or some such?

And then what would be the size difference of the FX-55 compared to those, and maybe compared to the next similar size Danforth HT?

I've always assumed -- once reaching a certain minimum weight, below which anchors may tend to "sail" through the water or "skate" along the bottom -- that size matters perhaps even more than additional weight.

?

I've always been pleased with our FX-37's performance here in the Chesapeake, and haven't even ever used the 45° angle yet!

-Chris

Chris, the Fortress model size indicates the approximate weight of a steel fluke anchor that is a comparable physical size, so the FX-37 is close in size to the 35 lb Danforth HT, and the FX-55 is similar to the 60 lb Danforth HT.

Regarding your second question, since an aluminum alloy is less dense than steel, it might be more likely to "sail" to bottom as you described, but as the weight and size increases, I think this becomes less likely.

Brian

 

[Bay Pelican]

OK this was a mud test and the Fortress came out fairly well. Have there been tests as to how well the Fortress does in vegetation? I don't mind carrying more than one anchor but it would be nice if I could get an anchor (for my second anchor) that does well in two of the three problem areas, mud, vegetation and rock.

 

[Mule]

I picked up an anchor, cost me $10, heavy sob weighed 20 pounds...maybe more. I put it on 100 feet of 1/4 inch nylon tipped by 10 feet of 1/8 inch chain, work great for my 28000lb 38 footer...cool...... Heading for shallow water...50 feet.

Is this about Chesapeake anchors....ugggg I thought it was cheapskate anchors....bye. Did I get cha??? I crack myself up......

 

[Djbangi]

One aspect that Fortress have indicated is that different anchors perform, very, differently in different seabeds and this aspect has not to my knowledge been raised previously (or not in such a dramatic way). Mud is a common seabed but has received minimal attention by anchor makers in the past - viewing the results we now know why (many anchors simply do not work in soft mud). But the tests also demonstrate that the Ultra and Spade perform or react differently as do the Supreme and Rocna.

Possibly Fortress have thrown down the gauntlet and we might see anchor makers looking a bit more critically at their marketing (their anchors are not all things to all seabeds) and it would be professional of them to better indicate where their products do not work (as opposed to swamping us with information and images of where they do work).

It is interesting that the reaction of the other anchor makers is muted - it makes something of a contrast to the verbiage of the past. Stunned into silence come to mind.

I, for one am grateful for Fortress investment. I know its part of marketing but the results are so stunning they cannot be ignored. I see this series of tests being discussed and quoted for years, decades.

I do not see a rush for people to buy Fortress, but I would be surprised if there was not an increased trickle. Despite the obvious benefits of the new designs I fail to notice that the new anchors have actually made much inroad into the market - but slowly they are being accepted - and I would expect the same growth, increased growth in their case, for Fortress. But this idea that owners buy bigger anchors - evidence of that is noticeable by its absence - if anything most owners appear to carry smaller anchors than look 'right'.


The biggest concern I have for the results is that The Fortress really needs to be set at 45 degrees to enjoy the benefits of their holding capacity in soft mud. Consequently if you are moving from seabed to seabed you need to alter the fluke angle as you move into areas of mud (as I understand for most sands you need the 32 degrees). Altering the fluke angle is not difficult (unless the nuts have corroded solid), but it is fiddly. I have this awful idea that the Fortress suggestion to overcome this issue is BUY 2 FORTRESS!, set one at 45 degrees and the other at 32 degrees.

Edit: Though the idea of carry 2 primary anchors, or more, would be part of any suggestion I would make to anyone asking.

 

[psneeld]

or buy none and just enjoy the other anchors that work so well for so many....

well ....maybe have one giant one in the bilge in case you are ever in the mind to ride out a hurricane someplace.

 

[Djbangi]

or buy none and just enjoy the other anchors that work so well for so many....

well ....maybe have one giant one in the bilge in case you are ever in the mind to ride out a hurricane someplace.

A valid point.

But If I'm going to make a 400nm cruise either north or south and elect to stop overnight then I must anchor in tidal estuaries and these estuaries, being sluggish, tend to have mud bottoms. I could take your advise and simply stay in our local waters, which also have a lot of mud (we have famous oyster farms nearby), and use the courtesy moorings. But certainly your advise is an option - but to my mind restrictive.

In the grand scheme of things a Fortress (or any other sensible anchor) is hardly expensive as part of an anchor armoury and on a per night basis if you anchor a lot - cheap as chips. I fail to understand your reluctance to invest in safety (and a good nights sleep).

I recall, in the depths of isolation, meeting someone who lost their primary anchor (and had no spare of comparable size/performance). They could only anchor after canvassing any other yachts to borrow an anchor for the night, or move on.

But each to their own.

 

[psneeld]

A valid point.

But If I'm going to make a 400nm cruise either north or south and elect to stop overnight then I must anchor in tidal estuaries and these estuaries, being sluggish, tend to have mud bottoms. I could take your advise and simply stay in our local waters, which also have a lot of mud (we have famous oyster farms nearby), and use the courtesy moorings. But certainly your advise is an option - but to my mind restrictive.

In the grand scheme of things a Fortress (or any other sensible anchor) is hardly expensive as part of an anchor armoury and on a per night basis if you anchor a lot - cheap as chips. I fail to understand your reluctance to invest in safety (and a good nights sleep).

I recall, in the depths of isolation, meeting someone who lost their primary anchor (and had no spare of comparable size/performance). They could only anchor after canvassing any other yachts to borrow an anchor for the night, or move on.

But each to their own.

BIG assumption on your part...because NO ONE HAS PROVEN beyond a shadow of a doubt which anchor will work when and with what technique.

I am a lot less locked into an anchor, system or technique than what it seems that you have bought into...but I sleep like a baby when I anchor...because I DON"T trust any of them to do what they say...I trust them to do what I know they will do under my guidance.

THAT's the difference between knowledge and experience.

And about the experience thing...you don't know much about tidal estuaries if you think they are all mud. Plus oyster shells are the curse of Danforth style anchors (untill you get into the larger sizes) where the average oyster shell gets impaled on a point of a Danforth type or wedged in the flukes and renders the anchor completely useless.

 

[Moonstruck]

A valid point.

But If I'm going to make a 400nm cruise either north or south and elect to stop overnight then I must anchor in tidal estuaries and these estuaries, being sluggish, tend to have mud bottoms. I could take your advise and simply stay in our local waters, which also have a lot of mud (we have famous oyster farms nearby), and use the courtesy moorings. But certainly your advise is an option - but to my mind restrictive.

In the grand scheme of things a Fortress (or any other sensible anchor) is hardly expensive as part of an anchor armoury and on a per night basis if you anchor a lot - cheap as chips. I fail to understand your reluctance to invest in safety (and a good nights sleep).

I recall, in the depths of isolation, meeting someone who lost their primary anchor (and had no spare of comparable size/performance). They could only anchor after canvassing any other yachts to borrow an anchor for the night, or move on.

But each to their own.

Rather than Chesapeake type mud, in SC and GA tidal currents run so swiftly that in some of the narrower anchorages the bottom has be scoured to a hard pan like consistency. A heavy pointed anchor is sometimes needed to penetrate the surface. I have had my Danforth skip over the bottom. The Delta dug in.

 

[Rex]

Djbangi Wrote:


It is interesting that the reaction of the other anchor makers is muted - it makes something of a contrast to the verbiage of the past. Stunned into silence come to mind.
Rex Wrote:

Well I have already commented, unfortunately I cannot on our product as it was absent for given reasons. Robertson tested our anchors over far more types than just hard substrates, we did make an attempt and were successful to show performance in many types of sea bed, more so than any other anchor test I have seen, further as a result of this extended testing our certification covers them all.

As Dbangi says hard soils do produce far greater holding power figures for anchors that can penetrate them, this is very true and many anchor designs that do well in mud are not always so hot in hard soils, little penetration can result in poor holding.

I have never challenged Brian’s Fortress anchors simply because in soft mud on 45 degrees those figure are as good as you will get, our anchors were designed as multipurpose, they have built a reputation as anchors that have served our customers well in multiple types of substrate, further confirmation of this is here in Australia, we actually cross over into the commercial industry, Large commercial boat builders fit many of our anchors as standard, I don’t know of any new anchor design in the last ten years, that has achieved this standard.

Anchor testing will continue, mixed results will continue, arguing the best, “well I’ve got the best” I think most modern anchor designs are an improvement, I also think many, not all but many have no idea how to use an anchor, they then run out buy a new generation anchor and find it still doesn’t work, so then they decide to investigate –learn how to lay an anchor, success at last, gee these new anchor designs are great?

If anyone is interested in Robertsons tests in multiple sea beds I think you will see some similar comparisons as to Brian’s testing, keeping in mind this test was for Super High Holding Power certification, it is what it is, if you go to our web site and click on anchor testing you will find Robertsons charts.

Static testing is what it is when comparing anchors, clogging from continuo’s dragging skews results in all anchors as compared to at boat hanging of one in all condition’s- all bottom types, one thing you can take out of testing in general when gauging performance, “an anchor design that clogs less” will be more reliable in all ocean types of sea bed.

Regards Rex.

 

[psneeld]

Exactly...my toolbox can carry dozens of tools but my bow is limited to one or two at best. I want what is going to work in a panic situation, and for most everyday anchoring situations. If I know I'm going to be in a special situation that a particular design excels in..then that may get swapped to the bow for a bit....but not if I can't trust it in emergency situations and in my experience...fortress is the worst for drop and forget ...quickly followed by other Danforth types. When they work...they are great...but I have had and my friends have had way too many slide and glide moments to trust our boats with them as a primary, go-to anchor.

Of course others will have different experiences because of different bottom types and techniques...great for you...bad for me.

 

[Djbangi]

BIG assumption on your part...because NO ONE HAS PROVEN beyond a shadow of a doubt which anchor will work when and with what technique.

I am a lot less locked into an anchor, system or technique than what it seems that you have bought into...but I sleep like a baby when I anchor...because I DON"T trust any of them to do what they say...I trust them to do what I know they will do under my guidance.

THAT's the difference between knowledge and experience.

And about the experience thing...you don't know much about tidal estuaries if you think they are all mud. Plus oyster shells are the curse of Danforth style anchors (untill you get into the larger sizes) where the average oyster shell gets impaled on a point of a Danforth type or wedged in the flukes and renders the anchor completely useless.

I actually have not bought into anything, I cannot think what gave you that idea. We carry 3 or 4 full sized (as recommended by the manufacturers for our size of vessel) anchors, of different designs or constructions. We are fortunate that our vessel is not large and can carry anchors sufficiently small we can change them relatively easily (nothing is easy at 2am in the rain). We also carry 2 full sized rodes, one mixed and one all chain and can cobble together more if push came to shove (as we carry lines to take ashore).

Its horses for courses, generally one has a vague idea what the bottom is like, and initial anchor choice is based on that vague idea - if it does not work then we change (anchor or location). However knowing that many/most anchors do not work, at all, in soft mud does tend to point us toward an anchor that does work.

I must confess we do lack experience (and probably equally lack in knowledge) as we only cruise about 3,000nm per annum. So I bow to a guru with true hands on experience. We have concentrated our activity over the last decade in what is apparently still called 'The Roaring Forties' but in the summer (we are too wimpish to go there in winter) we typically only enjoy one Storm warning a month - so we have much to learn.

And in support of Anchor Right, their Excels are , well excellent. Exceptionally versatile, largely drop and forget (this last comment slightly tongue in cheek - one does reverse up etc etc) and to be strongly recommended. It is a pity they were not included in the Fortress portfolio during the test.

 

[Peter B]

Some anchors do tend to pick up stuff and foul easier than others. The times my Danforth failed miserably back in my sailing days was when it picked up debris like weed, shells, or in some notable and embarrassing case, a discarded baked bean can on one fluke tip. The fact the Danforth has two points which slide along a bit before digging in makes them just that much more likely to do this. PSNeeld's cockle shells are a typical case in point, and would similarly tend to be picked up.

However, even my trusty Super Sarca managed to do this once, and I still marvel at it. We had just dropped her and done a gentle set for lunch in a spot I had never had trouble before. We started dragging dramatically, immediately, and just with current. I was flabbergasted. When I pulled her up, I noticed she felt really heavy, as if loaded with mud, but knew it was not a mud bottom. The reason turned out to be a large round-shaped rock, about the size of a volleyball, delicately balanced on the centre of the fluke. Don't ask me how it stayed there...it's a convex fluke, because as Rex says...better to leave bottom behind, and there was no mud sticking it on. The rock dislodged with a gentle tap of a boat-hook. Take a look at the fluke shape and explain how that happened...but it did. So, lesson is, any anchor can get fouled...some are just more prone than others.

 

[Nomad Willy]

Psneeld wrote;
".fortress is the worst for drop and forget ...quickly followed by other Danforth types. When they work...they are great...but I have had and my friends have had way too many slide and glide moments to trust our boats with them as a primary, go-to anchor."

There's some truth in this but I've seen numerous sizable GC boats with the Fortress protruding from their bows. And one could use a Fortress as primary and a Claw or other good rock anchor as secondary. Once a Fortress is set sleeping at night should be relatively assured. And if it dosn't set use another anchor.

Djbangi wrote;
"The biggest concern I have for the results is that The Fortress really needs to be set at 45 degrees to enjoy the benefits of their holding capacity in soft mud."

I disagree. Did you look at the 32 degrees chart? Very good performance I'd say of the drags that went well. I think only Mantus had no failed drags. Remember this was/is a troublesome area for anchoring. The Danforth HT had only one failure and excellent performance otherwise.

The thing I don't like about the 45 degree option is that at first you don't know what the bottom will need for a the best angle. One dosn't want to wake up dragging at 0300hrs thinking they should have set the angle at 45 degrees. How is one to know? If I had a Fortress primary I'd just use it at 32 degrees.

An interesting about the throat angle is that big heavy anchors like Navy, Dreadnought and Kedge type anchors mostly are only available w a 45 degree throat opening. With lots of weight for their size they must usually penetrate fine and so their holding power must be higher than their fluke area suggests.

 

[eyschulman]

I think I`d rather see an independent organization doing the testing, but maybe no one does, and this is the only way testing gets done. Is soft mud bottom a fair all round test for all anchors?

Practical Sailor a third party (no advertising magazine) has been testing all these anchors for many years under varying bottoms and scopes and conditions measuring multiple functions on repeated testing.. It will be no surprise that the fortress in soft mud will come out on top for holding power however there are many other aspects to an anchor doing its job and there fortress does not have the best record. If all that is being tested will be holding power in soft mud then I would think this is a set up for a fortress victory. I do think the fortress is well made and has its place and I did own and use one for years but not as a primary. This test to me is suspect because it is sponsored by fortress not to unlike drug testing done by the drug manufacturer. Because of this I would tend to believe the independent testing of Practical Sailor.

 

[Rex]

eyschulman
Wrote;
Originally Posted by BruceK http://www.trawlerforum.com/forums/...g-power-test-15941-post252607.html#post252607
I think I`d rather see an independent organization doing the testing, but maybe no one does, and this is the only way testing gets done. Is soft mud bottom a fair all round test for all anchors?

Practical Sailor a third party (no advertising magazine) has been testing all these anchors for many years under varying bottoms and scopes and conditions measuring multiple functions on repeated testing.. It will be no surprise that the fortress in soft mud will come out on top for holding power however there are many other aspects to an anchor doing its job and there fortress does not have the best record. If all that is being tested will be holding power in soft mud then I would think this is a set up for a fortress victory. I do think the fortress is well made and has its place and I did own and use one for years but not as a primary. This test to me is suspect because it is sponsored by fortress not to unlike drug testing done by the drug manufacturer. Because of this I would tend to believe the independent testing of Practical Sailor.
__________________
Rex Wrote;
For what it is worth our testing was done by a NATA test Authority commissioned by the N.M.S.C. National Marine Safety Committee. A compulsory test for certification.
Regards Rex.

 

[denloe1]

Really appreciate the data. Given what I know for the Columbia river area, which is mostly sand, I changed the PO's 33lb Bruce for a 55lb Delta fastset on 250 feet chain. #2 is an FX37 on a nylon rode with 30' chain. I have a very large Boeing Clipper Seaplane SS folding Northill I plan to put in bilge for storm with a nylon and chain rode. Maybe 36" shank and shovel size flukes at about 45 degrees. It would be fun to test that one. Northill ones are symmetrical. I see on commercial boats most often. What has made them lose favor? Maybe I should use a broken down FX55 for storm instead? Have that too but it is HUGE.

Here is "sister" Northill


Again thanks for the data and context!!
Dan

 

[Forkliftt]

I suspect a small part of the low use of this anchor is that it is hard to stow?. Of course, after looking over the graphs I have to at least consider sticking my easily stowed Delta 44 under the aft cabin bunk beside my rear water tank, and pulling my Fortress 37 outa there and getting it somehow stuck in the pulpit where it needs to be!!


1983 Present 42 Sundeck
Twin Lehman 135's

 

[Djbangi]

A number of members have queried the relationship between size (however you want to define size), of an anchor, and its maximum or ultimate holding capacity.

I can only find 2 pieces of work, from opposite ends of the spectrum, that have looked at this. John Knox in the UK looked at the relationship between anchor weight and hold for Bruce and Delta anchors. He published his results in the UK's Practical Boat Owner in August 2002 (long before some of the anchors tested by Fortress were released). John's work was on anchors upto 15kg in one seabed type (sand). Vryhof have published graphs of at least one of their anchors, weight vs hold in 3 different seabeds. The Vryhof charts are predictions but one assumes (maybe wrongly) that they are based on practical application. The Vryhof data is for anchors from 1t - 50t of an anchor that most closely looks like, with no disrespect to Vryhof, Danforth nor Fortress, a Danforth/Fortress (their Stevin Mk3).

Vryhof state, 2010 Vryhof Anchor manual, that performance is a function of weight (and separately suggest weight and surface area are interrelated). For an increase in weight they say you can expect an increase in performance but different designs will behave, more or less efficiently (so you cannot compare, say a Spade with a Mantus - you can only compare a big Rocna with a little Rocna, or a little Spade with a big Spade).

Both John and Vryhof come to similar conclusions that, very crudely, a doubling of weight results in a doubling of holding capacity.


I find the results slightly surprising, I'm simply reiterating what the conclusions are, as I would have thought that one would need to double surface area to double hold - just goes to show my thought process do not match practice!


Vryhof underline the results found by Fortress that in a soft seabed the fluke angle must be increased, though on their Stevin Mk3 their soft seabed fluke angle is 50 degrees (vs 45 degrees for Fortress) and in harder seabeds the angle is the same as Fortress at 32 degrees.

 

[ranger58sb]

Both John and Vryhof come to similar conclusions that, very crudely, a doubling of weight results in a doubling of holding capacity.

I find the results slightly surprising, I'm simply reiterating what the conclusions are, as I would have thought that one would need to double surface area to double hold - just goes to show my thought process do not match practice!

I'm not necessarily surprised by a conclusion that doubling weight doubles holding capacity... if it's also maybe true that doubling size increases holding capacity by some even larger number (or multiple). I don't remember seeing a comparison like that...

Chris, the Fortress model size indicates the approximate weight of a steel fluke anchor that is a comparable physical size, so the FX-37 is close in size to the 35 lb Danforth HT, and the FX-55 is similar to the 60 lb Danforth HT.

Regarding your second question, since an aluminum alloy is less dense than steel, it might be more likely to "sail" to bottom as you described, but as the weight and size increases, I think this becomes less likely.

Brian

Brian, that's what I'd always thought. I think you could have made an argument, then, that it would have also been fair to include a 32-lb FX-55 in the same tests.. since it weighs approximately the same as the 35-lb Danforth HT and most of the others.

Yes, I haven't seen our FX-37 "sail" anywhere. Haven't noticed any clogs from stuff like oyster shells, either, perhaps another potential hazard that generally decreases with anchor size and/or weight.

-Chris

 

[Nomad Willy]

I thought it was commonly thought that holding power is directly proportional to the blade area of an anchors fluke or flukes.

Seems to me Fortress made a dramatic demonstration of that.

But of course it's not that simple.

 

[Jeffrey S]

This test to me is suspect because it is sponsored by fortress not to unlike drug testing done by the drug manufacturer. Because of this I would tend to believe the independent testing of Practical Sailor.

I have to say that I love my Fortress FX-55 and I especially love the company. They stand behind their product and they make an exceptionally great anchor.

But...

I agree with the quote above. This entire test is very suspect. I'd even go so far as to say it was a marketing blunder. The fact that Fortress sponsored the event and is the one reporting on it (with Fortress logos on every page) throws doubt about the entire process to me. I'd love to know exactly who designed the test plan for all of this. This is not how real science is done except in the pharmaceutical industry and we know the long-term results of those study findings.

Again, I've had an FX-55 for almost 12 years on my trawler. For about 3 years of anchoring 50% of the time, 9 months/year, it was my primary anchor so I'm quite familiar with how it works on my boat. A whole lot of anchoring is technique and knowing how to use a particular anchor with your boat and knowing the cruising area you're. Anchoring in the Chesapeake has subtle differences to anchoring in the Bahamas.

Today the Fortress is my #2 anchor. It has exceptional qualities as a backup anchor (weight and disassembly) but there is no question that my current primary anchor is significantly better at grabbing quickly, holding with reliability, and handling full 180 degree swing in a real anchoring situation. I can guarantee that my anchoring technique is different than the tests performed within this study and most certainly account for some of the differences in experiences I've had with different anchors.

 

[psneeld]

I have to say that I love my Fortress FX-55 and I especially love the company. They stand behind their product and they make an exceptionally great anchor.

But...

I agree with the quote above. This entire test is very suspect. I'd even go so far as to say it was a marketing blunder. The fact that Fortress sponsored the event and is the one reporting on it (with Fortress logos on every page) throws doubt about the entire process to me. I'd love to know exactly who designed the test plan for all of this. This is not how real science is done except in the pharmaceutical industry and we know the long-term results of those study findings.

Again, I've had an FX-55 for almost 12 years on my trawler. For about 3 years of anchoring 50% of the time, 9 months/year, it was my primary anchor so I'm quite familiar with how it works on my boat. A whole lot of anchoring is technique and knowing how to use a particular anchor with your boat and knowing the cruising area you're. Anchoring in the Chesapeake has subtle differences to anchoring in the Bahamas.

Today the Fortress is my #2 anchor. It has exceptional qualities as a backup anchor (weight and disassembly) but there is no question that my current primary anchor is significantly better at grabbing quickly, holding with reliability, and handling full 180 degree swing in a real anchoring situation. I can guarantee that my anchoring technique is different than the tests performed within this study and most certainly account for some of the differences in experiences I've had with different anchors.

Absolutely....

Nothing wrong with being number 2...the backup quarterback always suits up and sometimes even becomes the hero....but still the backup...

 

[caltexflanc]

Jeff if you read the thread from start Brian described the methodology and it's designers pretty thoroughly.

You bring up an excellent point others have made as well. About 80% of successful anchoring is technique, and that is is selling it short, especially if ground tackle is in specs for that size boat, regardless of anchor design. All these different tests by different people really tell you is how different anchors hold using one identical technique and tested in one particular manner. I find them interesting as a triangulation point, but not as sole the basis for decision making. In my now pretty extensive anchoring experience up and down both US coasts, in a a wide variety of conditions, using primarily CQR (many charter boats), Delta (main on my Hatteras, also charter boats) and Danforth (used as both main and backup on Hatt, also on many sailboats and charter boats and our Boston Whaler dinghy), I have found one constant in not getting a good set: my taking some kind of shortcut in the process.

I've posted this pic before, but I consider this type of situation to be an example one of my true tests of an anchor. This particular bottom was what I'd call "medium" mud. Clocking tidal current, residual winds maybe max 10 knots. Then, a sustained squall from out of the NW, max gust in the 40's, sustained maybe 25-30. Then after a few hours, back to normal.

Now, this is obviously a very hard thing to replicate in any kind of scientific study. Which why these types of controlled tests can only be used as one data point.

 

[Anchor Brian]

This entire test is very suspect. I'd even go so far as to say it was a marketing blunder. The fact that Fortress sponsored the event and is the one reporting on it (with Fortress logos on every page) throws doubt about the entire process to me. I'd love to know exactly who designed the test plan for all of this. This is not how real science is done except in the pharmaceutical industry and we know the long-term results of those study finding

Jeffrey, I appreciate your healthy skepticism. We had members of the boating media aboard who represented combined magazine circulations of about 1 million readers, and we could have certainly waited for them to publish their test reports, a couple of which will be made public within the next 30 days or so.

In the meantime, you are welcome to have review images that have been posted from the testing on Dropbox, and I will share links as well to YouTube videos from all 4 days of testing in the near future:

Chesapeake Bay Test Images

Brian

 

[Anchor Brian]

And here's the video from Day One....and the Fortress did not set in its first attempt!