Fortress for general use?

[dhays]

I never had problems with over 25 years anchoring until I purchased my Silverton and took the effort to totally enclose the boat. The canvas increases the wind loading substantially.

Most flybridges here in the PNW have complete canvas enclosures. While that makes some sense in our region due to the typically cold and wet weather, I have never been comfortable with the added windage. I have enough windage as it is without adding more.

Anchoring is not my concern with that to be honest but simply docking and sailing at anchor.

 

[ranger58sb]

AAAhhhh technique! Would you elaborate please? Is there a special technique known only to the chosen and the uninitiated commoners left to slowly lowering an anchor, letting one's boat gently tug on the rode for a short time prior to setting it with applied force? And of course there is always the need for scope. Chapman's book highly recommends 10 which is completely impossible in our crowded harbors.

I think that varies a bit by specific anchor, though. IIRC, Fortress suggests setting at 5:1 (or shorter in some situations) before choosing final scope. IIRC, SuperMAX recommends setting at about 3:1 before making final scope adjustment. Maybe others have their own recommended techniques, too...

-Chris

 

[jleonard]

I think that varies a bit by specific anchor, though. IIRC, Fortress suggests setting at 5:1 (or shorter in some situations) before choosing final scope. IIRC, SuperMAX recommends setting at about 3:1 before making final scope adjustment. Maybe others have their own recommended techniques, too...

-Chris

Not by recommendation, but by MY experience, I let the wind set my Danforth at "about" 5:1 AFTER the anchor flips to the right direction if it's not there initially (which we try to do).
Then we let out usually close to 10:1 let the wind set it further, ,then I'll set up the snubber and idle in reverse to set it.
I sit often for several directional shifts and with my rode/boat combination it resets. I believe that the anchor sets deep enough to resist fouling.

 

[jleonard]

Quote:
Originally Posted by Nomad Willy View Post
How big is your Dan?
It's a 35 lb high tensile.


Like the Dan on the left .. or the right?
In my pic the left Dan has forged flukes and shank.
The one on the right (much more common) has a forged shank and L shaped (inboard) bent sheet metal flukes. the attach point where the stock goes through the shank reveals a far more robust shank attach eye on the left anchor.

QUOTE]

I don't see your picture. Mine has a forged shank.
If you zoom you can see mine in the pic below

 

[Anchor Brian]

I'll second that. I used to use my Fortress a few years ago (8 maybe?) as my main. I anchored and stayed for a few days with no issues. We spun around a few times due to changes in wind and, in some cases tide when the wind was calm.

I even dove on it on the late afternoon of the 3rd day. The chain was making a lazy spiral with a radius of maybe 10 feet around the anchor and just a speck of the tab and one stabilizer bar exposed. I went into shore to have dinner on our last night. When I came back out the boat was gone.

The wind had picked up a bit causing the chain to sweep the anchor and foul it. now the boat is pulling the chain and the chain is pulling the back of the anchor and it popped. It couldn't reset as it was a ball of chain and anchor skidded across a sandy seabed that should have very good holding.

The boat was salvaged and I got a $5,000 bill from the salvage company.

Their official position to address such concerns is to deploy TWO anchors.

I still have a Fortress, but use it as a stern anchor. It hasn't seen the water in 7 years. I had told this story on a few forums and then the Fortress marketing team asked me to 'cease and desist'. I won't, however I found it very comical.

I've used a Rocna, a Manson Supreme. I currently have a Rocna Vulcan which is very similar to a Spade. I would never use a Fortress a main anchor again.

Shrew,

Thanks for your input and sorry to hear of your bad experience. Our late company founder was a very adventurous and lifelong boater, with a 1,000 mile trip up the Amazon River, several Atlantic crossings, and a circumnavigation on his resume.

He fully understood that NO anchor will dependably reset 100% of time, and he once said that when an anchor breaks free from a sea bottom, it is oftentimes no longer an anchor....it is a ball of sediment with no sharp edges in which to re-engage the bottom.

This is the reason why he always recommended setting two anchors for maximum safety, and not because of an inherent weakness in our product.

Additionally, during my 20 years with the company, in the very few instances I have heard of when a Fortress anchor did not remain embedded in a sea bottom during a wind or tidal shift, the anchor was undersized for the boat, wind, and sea bottom conditions.

Further still, during my time with the company we have NEVER told anyone to cease and desist commenting about our product, in fact, I encourage the discussion. When you have been selling anchors for 30 years and have roughly 600,000 out in the world boating market, then you can rest assured that not all comments about your product will be positive, particularly given the variances in bottom conditions and anchoring techniques among boaters.

 

[Anchor Brian]

"You'll likely have seen the results of the Chesapeake mud tests; what they found (relative to Fortress anchors and our mud) is what we've found. Can't speak to most of the other anchors in those tests. And of course you may not have mud."

The Chesapeake tests were run out of the Maryland Marine Biological Laboratory in Solomons MD. Their high tech research ship Rachael Carson was used for the tests. In the anchor test write up, much was made of the capabilities and precision of of the ship. The anchor tests were odd and did not reflect real world anchoring. The testing protocol was designed by and was paid for by Fortress. And guess what anchor won! Amazingly it was the Fortress. The following year I was at the MD MBL to write a story for Chesapeake Bay magazine about one of the graduate student research projects there. By that time, the staff at the MD MBL was already saying, "Well I'm sure you have read by now the results of our thoroughly discredited tests". They recognized that the test protocol was unusual.

Tadhana,

Thank you for your input as well. For the sake of accuracy, we chartered the Rachel Carson at a cost of $275 per hour + fuel from the University of Maryland Center for Environmental Science in Solomons, MD. The captain aboard was Michael Hume, the Director of Marine Operations and the Engineer-Mate was Rob Nilsen. You are certainly welcome to contact either of these men for their firsthand knowledge of the testing.

This holding power test was also attended by technical editors and well-experienced boating writers who represented magazines with over 1 million readers and none of them wrote in their follow-up articles anything about the test being "discredited."

Prior to this test, we had been exhibiting at the US Sailboat show for 15 years or so, and I had heard ongoing complaints from Chesapeake Bay boaters about the difficulties getting their anchors to set and hold in the soft mud bottoms, particularly during thunderstorms which oftentimes had significant wind gusts.

We certainly knew going in that our product design, with the capability of adjusting the shank / fluke angle to a wider opening (from 32° to 45°), would result in superior holding in this type of sea bottom.

While we hold a patent on this feature, it is certainly no great secret among large anchor manufacturers such as Bruce, the US Navy, and Vryhoff, as they all make anchors with a wider shank / fluke angle to improve performance in soft mud.


During the initial set up for the testing, we found that the boat was too big, the bottom too soft, and and anchors too small to achieve controlled, repeatable results. Under the guidance of Robert Taylor, a retired US Navy anchor design and soil mechanics expert with close to 50 years of experience, we decided to use the state of the art Dynamic Positioning System aboard the Rachel Carson for the testing.

This way every anchor would be pulled with the exact same starting scope and for the exact same distance, time and speed which was measured into the thousand decimals by a running line tensiometer at a cost of $5,000 per week. The results were monitored in real time on monitors that were set up aboard the vessel.


While many aboard were surprised at the test results, particularly for the highly-touted "new generation" anchors, Bob Taylor certainly was not, as he stated afterwards that "anchors which are designed and optimized for harder soils will typically only have a holding ratio (holding power divided by weight) of 10-15x when used in softer soils."

That is almost exactly what we found in the Chesapeake Bay, as the average peak holding power for many of the 44-46 lb anchors was typically only 450-700 lbs.

Additionally, during several of the pull tests some of the fixed fluke anchors basically skidded through the soft mud without much of a spike in tension. Afterwards it was suggested that if a roll bar anchor (such as a Rocna) landed on its side or upside down, then it would just sink into the soft mud and not be able to orient or turn into the fluke downward position.

Simply stated, a roll bar anchor needs a harder soil in order to roll. This also signified the advantage of the Danforth design with pivoting, movable flukes, as there is no upside down position.

As a side note, here is an interesting "pound for pound, kilogram for kilogram" weight comparison. Oftentimes people will buy a Fortress for the weight savings, but if weight is not an issue, then the performance is not comparable in common bottoms such as sand, mud, or clay.

 

[Art]

Yup - What the Fortress fellow said! I fully agree...

On our 34' Tolly Fortress FX 23 is my favored anchor. I have shank set at 45 degrees. This eve we will set her in SF Delta mud bottom... for a few to several days!

Art

 

[AusCan]

I'm sure a Fortress is a great anchor suitable for the conditions many people boat in.
It all depends on what your bottom looks like. Any one single anchor is not the best for all conditions. One anchor may be the overall best for "your" area, but a terrible choice for somewhere else.

The predominate bottom in this area is limestone with a heavy weed growth. Many anchors that rely on a shovel design or a wide fluke don't do so well in this. The weed often fouls an anchor which has a narrow gap like the Fortress.

The type of anchor I have would be useless in soft mud, but a mud bottom is a rarity around here.

My point is that a question about what anchor is best is impossible to answer unless the type of bottom(s) is specified.

 

[psneeld]

A bunch of experienced boaters all knew the Fortress would win that test for holding power before it was even run. It wasnt a suprise at all.

Those same people have real life experience with a bunch of different anchors and only a minority choose Fotress or Danforth types as their primary anchors....no matter how many anchor tests are run.

But many like me keep a large Fortress as a backup, storm, kedge, soupy bottom anchor because it will hold when nothing else will, as long as you have time to make sure it sets well.

 

[jleonard]

My point is that a question about what anchor is best is impossible to answer unless the type of bottom(s) is specified.

OK, I'll bite (pun intended).
In my normal cruising area, the bottom is predominately mud. Usually pretty thick, and the Danforth works well.
When we cruised in Canada, I changed my anchors around and made my 44 Delta the main as the bottom was often weedy where Danforth styles don't do that well.

 

[tadhana]

Fortress Anchor
Test set up
1. Rode is 20’ of chain + 200’ cable = 220’ scope
2. Assume 27’ water + 4’ to working deck=31’
3. The anchors start with 220/31=6.9:1 scope
4. In the test the winch will pull in 10’/minute for 10 minutes and at end of test you have 120’/31’= 3.9:1 scope.
• At 3 minutes, the scope is 190’ for a ratio of 6.2:1
• At 4 minutes, the scope is 180’ for a ratio of 5.6:1
• At 5 minutes, the scope is 170’ for a ratio of 5.3:1
• At 6 minutes, the scope is 160’ for a ratio of 5.2:1
• At 7 minutes the scope is 150’ for a ratio of 4.8:1
• At 8 minutes, the scope is 140’ for a ratio of 4.5:1
• At 9 minutes, the scope is 140’ for a ratio of 4.2:1
So, unlike many other anchor pull tests with set scope, this test has a varying scope. The winning anchor will be the anchor which can hold the best with the shortest scope. The fortress with the 45 degree “mud” set is just such an anchor. But we do not know how the other anchors would perform with a constant scope and an increasing load, which to me seems like a better replication of the real world. In the real world, as the wind builds and the load comes up, most cruisers let out more scope. Hence my comment that this is an odd test.
What I did notice is that in many of the pulls, the load plateaus at about the 3-minute mark. At that point, the scope has dropped below the theoretical preferred 7:1 ratio.
A number of tests had an abrupt change at about the 6-7 minute mark when the scope hits and falls below the 5:1 ratio.
This test does seem to lead credence to the 7:1 and 5:1 rules of thumb.
So, my comments are just comments of one cruiser. And at the risk of forging into the battle of “I’m saltier than you.” I would like to give you an idea of my background to provide some perspective on my comments. Feel free to PM me for my background which is entirely on the technical and engineering side in the marine industry.

 

[Nomad Willy]

Hard to follow you talking bout scope as a number. It's always a ratio of two numbers.
And the load (pull) is .... what? Usually an anchor test is a load (in lbs) at a given scope. You're an engineer what would produce those numbers? In your test the winch is pulling with what force? The boat is free floating so unless there is significant wind or current ... what would the winch be pulling against?

Oh I see .. You're not talking about your own test but the Chesapeake Bay test by Fortress.
Now I'm trying to see what your point is. Has something to do w the pull changing at various scopes. And then there's the 5-1/7-1 scope thing. Are you trying to point out that scope from 5-1 to 7-1 is the best scope? That won't fly as there is a lot of variables to anchors like throat angle, length of shank ect. Generally speaking the Supreme seems to have the best low scope performance. I like to buy anchors w good short scope performance as most any anchor will do well at 7-1 but not many shine at 3-1 or less.

How would you test for performance at 3-1 scope?

 

[Anchor Brian]

Fortress Anchor
Test set up
1. Rode is 20’ of chain + 200’ cable = 220’ scope
2. Assume 27’ water + 4’ to working deck=31’
3. The anchors start with 220/31=6.9:1 scope
4. In the test the winch will pull in 10’/minute for 10 minutes and at end of test you have 120’/31’= 3.9:1 scope.
• At 3 minutes, the scope is 190’ for a ratio of 6.2:1
• At 4 minutes, the scope is 180’ for a ratio of 5.6:1
• At 5 minutes, the scope is 170’ for a ratio of 5.3:1
• At 6 minutes, the scope is 160’ for a ratio of 5.2:1
• At 7 minutes the scope is 150’ for a ratio of 4.8:1
• At 8 minutes, the scope is 140’ for a ratio of 4.5:1
• At 9 minutes, the scope is 140’ for a ratio of 4.2:1
So, unlike many other anchor pull tests with set scope, this test has a varying scope. The winning anchor will be the anchor which can hold the best with the shortest scope. The fortress with the 45 degree “mud” set is just such an anchor. But we do not know how the other anchors would perform with a constant scope and an increasing load, which to me seems like a better replication of the real world. In the real world, as the wind builds and the load comes up, most cruisers let out more scope. Hence my comment that this is an odd test.
What I did notice is that in many of the pulls, the load plateaus at about the 3-minute mark. At that point, the scope has dropped below the theoretical preferred 7:1 ratio.
A number of tests had an abrupt change at about the 6-7 minute mark when the scope hits and falls below the 5:1 ratio.
This test does seem to lead credence to the 7:1 and 5:1 rules of thumb.
So, my comments are just comments of one cruiser. And at the risk of forging into the battle of “I’m saltier than you.” I would like to give you an idea of my background to provide some perspective on my comments. Feel free to PM me for my background which is entirely on the technical and engineering side in the marine industry.

To simplify:

We calculated an initial starting scope of 5:1 + 100 feet, and so the initial starting scope was approximately 8:1. We then pulled back the anchors that extra 100 feet at a rate of 10 feet per minute, so the entire pull test was 10 minutes, and the finishing scope was 5:1.

Here is what Bob Taylor wrote in his test report about this setting method and the possible negative affect of the decreasing scope:

4.7 Scope Influence
Each anchor test started out with an 8:1 scope and ended after 100 feet of drag at a 5:1 scope. There was concern that the scope change could dramatically influence anchor behavior. I evaluated both a high load and a low load case at various scopes using Navy analysis tools (1,2) described in 4.2. The code CSAP allows calculation of line configuration from the surface to an embedded anchor and can accommodate multiple line types, weights, buoys and up to 17 soil layers.

This unique program was validated with full-scale data and has been used by the Navy for many years to design fleet moorings. The anchor shank depth and load are inputs to the code.

At a 2100lb load the maximum depth of embedment for the shank shackle on the FX-37 anchor in a normal mud is about 11 1/2ft with this mooring line. This places the center of the anchor at about the 13ft depth and the fluke oriented such that it can no longer penetrate the seabed. Essentially the anchor and mooring line are in an equilibrium position.

Note that two angles are illustrated on the chart, the angle α at the anchor shank and angle β at the seafloor surface. Water depth at the site was only 30 feet so catenary is influenced significantly by the fact that the end of the chain is 11 1/2ft in the seabed.



Figure 8 and Table 1 show that line angle at the anchor is hardly affected by the change in scope from 8.1 to 5.1. Angle α changes 1.2 deg while angle β 6.5 deg.

The change at the anchor might have a very minor effect on the anchor’s maximum embedment but it won’t be noticed in the scatter of the data. I also checked behavior at the 500lb load, which is more typical of most of the fixed fluke anchors. At this load the anchor body is located at about 5 feet into the seabed with the shank at 3 feet. A 3 degree change at the seabed causes only a 0.5 deg change at the anchor. This will not influence anchor behavior at all.

Although it is desirable to maintain a constant scope during a test, it seems that the test process employed at Chesapeake where scope was changed during the test had minimal affect on the test.


Concerning the "real world conditions," we all know that surging seas can also cause a reduction in scope, and yes, in those circumstances a cruiser might lay out more rode to compensate.


A final point is that we actually handicapped our anchors with the setting method used in the Chesapeake Bay. We ignored our own advice that is provided in the Safe Anchoring Guide which is included with every anchor that we sell.

As per the image below, this advice calls for using an initial shorter scope of 2:1 or 3:1 in soft mud in order to prevent the shank from sinking below the flukes. After the anchor sets, we then recommend letting out a 5:1 scope or greater and then to "power set" the anchor.



Since other manufacturers do not offer this same advice with their anchors, we did not believe that it was fair to impose this setting method on their products.

And so during the very first pull test of the Fortress anchor, and under the watchful eye of the boating media, the Fortress just slid right across the soft mud bottom. One writer commented in his story that he overhead a Fortress representative stating that "Well, at least they can't say that this test was rigged."

Fortunately he did not hear me wondering out loud if a nearby bridge was high enough to jump off of.....

However, after 48 pull tests and noticing that many anchors were having difficulty setting, we tried a shorter scope setting method for the last series of 12 tests to see if that would have an affect on the other anchors.

We thought we might learn something that we could pass along to their owners, but unfortunately using a shorter scope did not make a noticeable difference in their performance.


We would also welcome at any time soft mud test data from other anchor manufacturers which would challenge our findings about the performance of their products. Its been three years since the August 2014 testing and I have not heard from anyone, other than Randy from Ultra who stated right afterwards that he felt the test was conducted fairly and that the results were to be expected.

 

[tadhana]

Good morning. My calculations of scope ratio, were based on the stated water depth of "about 27 feet" as stated in the write up, and my guess as to the height of the working deck above the water which I guessed to be 4' for a combined height above sea floor of 31'. using those assumptions as our starting point, the starting scope ratio would be just under 7:1. It then yields a test ending ratio of just under 4:1.

Bob Taylor has unique knowlege and experience regarding the bottom sediment structure. It brings a unique perspective to anchor testing. I read with interest his assertion that the Fortress anchor was buried 13.5'. It would be interesting to have some way to find out if the anchor really is that deep in the mud? Based upon my experience, I do wonder if perhaps there is a factor of scale here. Was Bob's engineering based upon ship anchors or small craft anchors? Does it make a difference?

Over the past 45-50 years I have used several different anchors, including the Fortress. I have enjoyed many a night confidently at anchor with 4 other boats rafted to us and only the one Fortress here on the Chesapeake. Still after experiencing the anchor sailing and not submerging, and after having it pull out and not reset. I drifted away from the Fortress, though I still have one aboard as my stern anchor.

Presently we are using a spade type anchor. We have used it from the Keys to Lake Champlain and New England. It seems to set quickly no matter the bottom and we back down with 80-100 hp it has not failed us in the reversing currents in the SC an GA ICW. Each style of anchor has its preferred conditions. Were we still only cruising the Chesapeake, we might not have changed anchors.

 

[Anchor Brian]

Good morning back to you. Bob Taylor was using information that was provided by Rob Nilsen, the Engineer-Mate and aft winch operator during the testing.

While retrieving the 21 lb (10 kg) Fortress FX-37 after it had reached 2,100 lbs of tension during one pull test, and directly above the anchor at a 1:1 scope, Rob calculated that the FX-37 was buried approximately 13 feet into the mud below the 81-ft Rachel Carson research vessel.

We ended up breaking the wire rope at about 3,500 lbs, as noted below in this test chart.

 

[Art]

A "practical-anchoring" side note is offered in this post... no graphs nor fancy %age numbers to speak of. Just good ol' 2017 Labor Day weekend Fortress anchor experience by a boater [with a bit of similar, previous, over the years anchoring experiences thrown in at end of the post].

Fortress Anchor - FX-23... securing in place a 34', 21K loaded lbs., considerable windage Tollycraft boat:


This Labor Day we used our FX-23 as a back anchor. Super muddy bottom of a SF Delta Slough. We'd already [by means] firmly attached front of boat [keeping her nose about 15' off shore] to thick foliage on an island. This gives us a couple feet water under boat nose and some 16' of tidal cleaned/cleared swimming water at stern.

Took our Fortress [having 15' +/- of 1/4" chain attached to 5/8" line] off the back of boat in our runabout. Dropped the anchor at about 150' off stern of boat in approximately 19" of water. Transom about 4"6" off water = 23'6" +/-. You can calc the scope %age if desired. My decades of boating makes my eyes know when the correct scope is in position.

When I drop the FX-23 off runabout I do so with Linda already pulling the rode somewhat tighter and inward toward boat's transom on the line... so the Fortress anchor flukes "sail" fully extended [at the available 45 degree angle off shank] downward toward the bottom.

Once anchor hits bottom and initial set is experienced... Linda keeps tension on the line till I gat back to boat. At that point... standing on swim platform I take over and begin pulling in on the anchor line. Usually [this past weekend included] I meet considerable resistance within about 6' to 10' of pulling in [mostly from just straightening out the rode]. I then climb up to the transom deck and with feet firmly against railing stanchion and work gloves on I pull on the line with all I'm capable of in that relatively comfortable position [guestimate about a 175 lb. repeated tugs on anchor... been a heavy-weight lifter all my life, I know the poundage I do].

Fortress anchor sets and can not be moved by me. I then tie off the anchor line to starboard transom cleat. From my pulling on anchor line the front line to shore and rear anchor line have the boat well placed at beam to the tidal flows that will happen over and again. I'd say about 3.5 knots top current speed and some times up to 25 knot winds broadside to the boat [there was not much wind this past weekend]. Our consistent experience has been that these winds and changing direction [broadside]currents set the Fortress anchor deeper.

When we up-anchor at end of weekend I first retrieve the front holding apparatus. That leaves back anchor still attached as it was all weekend. Tidal current [in either direction] immediately begins moving boat off shore; into tidal flow. I go back up on bridge and Linda gently pulls in rear anchor line as I slowly reverse toward being directly over top of anchor. When line is straight down off transom Linda refastens line to cleat. Boat's engines break anchor free. I then come to stern and pull anchor up to transom deck [often needing to "ker-plunk' the anchor into water to get mud off her flukes]. I go back upon bridge and Linda stores the anchor, chain and line in a manner we devised. From there it's clear sailing to what ever or wherever we may be going.

Other anchoring experiences with the FX-23:

At times under same conditions the Fortress just would not set as I'd be on transom pulling in the line. Most of the times it has been due to a sunken tree limb wedged in between the flukes and shank. Once it was an old fishing rod with reel and once it was a little mushroom anchor. In those instances we'd redeploy the anchor as described above and she would then set.

We have found that FX-23 works very well to fulfill our needs. Having spent many decades using considerable weight Danforth anchors I am convinced that the dual fluke design is really good. And, I am very pleased to have Fortress provide similar design with light weight for handling purposes and the 45 degree angle of flukes to shank for better/easier setting into mud bottoms.

We have not used our FX-23 in areas where 180 degree boat angle reversals due to current change or shifting winds come into play. That said... many times I have successfully used Danforth anchors while experiencing those condition changes.

IMO - Fortress anchors represent 21st Century Danforth design "On Steroids"!

 

[FF]

"We have not used our FX-23 in areas where 180 degree boat angle reversals due to current change or shifting winds come into play."

Mr Ogg , the Danforth inventor suggests never anchoring with a single anchor , use 2 one set from aft lead to the bow as the solution.

Works for us as a steel 20H is light to set and recover .

 

[Anchor Brian]

An anchor's capability of burying deeply into a sea bottom, along with its design + fluke surface area, will certainly be factors in how well it compresses sediment and remains embedded into a sea bottom.

With Irma looming in our Florida hurricane region, I suspect that many anchors will put to the ultimate test and hopefully all will perform admirably.

 

[FF]

"I suspect that many anchors will put to the ultimate test and hopefully all will perform admirably."

Finally folks will see some stretch in their frequently way oversized anchor lines.

 

[tadhana]

Here on the Chesapeake we are beginning to think Irma might still have some strength when she gets up here. I was thinking about putting two anchors in series. A naval architect friend says that a Navy study showed that the theory does not lead to increased holding power. Anyone have any thoughts pro or con?

 

[psneeld]

I am not sure about increase holding over 2 separate anchors, but over just one if properly done, I cant see how it could hurt ...unless you drug a bunch and a large foul interfered with the primary.

There are pros and cons to tandem and just 2 at 45 or so degrees to prevent as much yaw.

Really depends on what you expect in wind shift and wave action....and even then..... I say it is a crap shoot to which is better.

I think the biggest thing, is a better hurricane hole....not necessarily the anchor (s).

 

[foggysail]

Getting them up will be a bear

 

[Nomad Willy]

Here on the Chesapeake we are beginning to think Irma might still have some strength when she gets up here. I was thinking about putting two anchors in series. A naval architect friend says that a Navy study showed that the theory does not lead to increased holding power. Anyone have any thoughts pro or con?

For openers it could be much like twin engines. When one quits all you've got left is one, usually half size. A half sized engine works great as a spare but not so w anchors. The first anchor on the rode (the far one) will be very unlikely to break out at the same time or after the 2nd anchor (the near one). So I agree w the NA.

 

[Anchor Brian]

Here on the Chesapeake we are beginning to think Irma might still have some strength when she gets up here. I was thinking about putting two anchors in series. A naval architect friend says that a Navy study showed that the theory does not lead to increased holding power. Anyone have any thoughts pro or con?

Here's a link to a Dropbox folder with three papers that were co-authored by Bob Taylor regarding tandem, or piggyback, anchoring.

I think that the paper titled "anchor drag NCEL N-1774.pdf" provides the most detail:

US Navy - Bob Taylor


Here is a page from one of the reports and Bob's comments to me are below it:




"The best way to use Fortress and most other anchors with this configuration in tandem is to use option 4 in table 2 of the Tech data Sheet. This allows each anchor to function properly. In reality the rear-most anchor will eventually move into the trough created by the front anchor and dig deeper than it normally could resulting in more than twice single anchor capacity."

 

[psneeld]

Was that study for just Fortress anchors or navy style?

If mixing anchor types, what order?

I think others have suggested the danforth as the farthest from the boat if crown shackled.

Sorry, couldnt open links on phone

 

[Art]

Post # 54:


Table 2 / #1 GLOptions / OGuidlines states: "48 [degree] fluke angle for mud".


I imagine that means the shank to fluke angle?? Your thoughts on that wide an angle...

 

[Bigsalmonfish]

Just finished a 2 month cruise into British Columbia. Used my Fortress as my primary anchor. Experienced all different types of bottoms. Routinely I had at least one or two 40 foot boats tied to me. Glendale Cove was the most challenging as I set in 150 feet and it comes up quickly to 10 feet in the stern. A stiff wind came up and we moved across the delta. After deploying 275 foot of chain we were settled.

Our last place was Labor Day at Roche Harbor. It's bottom is covered with a sea lettuce which is difficult to penetrate. I've seen many spade, danforth, rocnas, Bruce's have difficulty. I set in 55 foot of water with 200 foot of chain out. Had a 52, and two 40 foot boats tied all weekend. The current comes through and we reversed several times. No problems except retrieving as the anchor was set pretty deep.

I'm very confident in my Fortress.

 

[Nomad Willy]

Salmonfish,
Thanks for the post.
I don't see why more people don't use the big F more often as the main. It seems most are worried about reversals and not resetting. I think if an anchor sets in the first place it should set again on the same bottom. Lesser Danforths frequently bend shanks but I'll bet that's a very rare occurance w the Fortress.
And if the F dosn't innitially set just use another anchor. But that also is (I'm sure) a rare occurance.
So it would seem to me most all the time the F will perform extremely well.

What I propose is the reverse of what most people do w the F. But using the F as a primary is taking advantage of the extraordinary performance it has most all the time. Most people use a lower performing anchor most of the time. But why settle for less when better is an option. The answer is that most people think their anchors work more often than the F. I think it may be a myth. There is great fear of an anchor failing. Marin Faure thought his new anchor was bulletproof. It isn't/wasn't. No anchor is. But many actually feel their anchor is bulletproof.

But using a Fortress makes sense to me.

 

[jleonard]

I don't see why more people don't use the big F more often as the main. It seems most are worried about reversals and not resetting. I think if an anchor sets in the first place it should set again on the same bottom. Lesser Danforths frequently bend shanks but I'll bet that's a very rare occurance w the Fortress.

You all know I am a Danforth guy
In MY experience it is NOT that the Danforth style will not set upon reversal, It's that the chain/line can wrap around the shank or the side bars and foul. I mean that has happened to me several times in my old boat when I had chain/line combo rode. We would simply pull up the anchor if we suspected that (happened from time to time in a certain anchorage) and re-drop.
A few times it came up fouled. And when it's fouled its just a 20 pound blob.

Knock on wood it has not happened with all chain rode on my current boat/setup.

 

[Bigsalmonfish]

Salmonfish,
Thanks for the post.
I don't see why more people don't use the big F more often as the main. It seems most are worried about reversals and not resetting. I think if an anchor sets in the first place it should set again on the same bottom. Lesser Danforths frequently bend shanks but I'll bet that's a very rare occurance w the Fortress.
And if the F dosn't innitially set just use another anchor. But that also is (I'm sure) a rare occurance.
So it would seem to me most all the time the F will perform extremely well.

What I propose is the reverse of what most people do w the F. But using the F as a primary is taking advantage of the extraordinary performance it has most all the time. Most people use a lower performing anchor most of the time. But why settle for less when better is an option. The answer is that most people think their anchors work more often than the F. I think it may be a myth. There is great fear of an anchor failing. Marin Faure thought his new anchor was bulletproof. It isn't/wasn't. No anchor is. But many actually feel their anchor is bulletproof.

But using a Fortress makes sense to me.

I bent shanks on my other Danforth and keep waiting for the same to occur on this one. So far it's pretty scratched up and has lost its shine. Rocks are tough on any anchor. Don't mind the scrapes...just wished it was shiny again as it is displayed prominently on the billboard.