Anchoring Perfectionism vs Realities of Soft Mud

[Dockhead]

Originally Posted by Don C L

. . . I was just saying that since you did point out the virtues of the Fortress setting and holding in mud, the solution to its weakness is to set two at 180 degrees to each other.

Yes. As actually recommended by the Fortress founder. I guess I need to buy one more Fortress

[ranger58sb]

Originally Posted by Dockhead

Yes. As actually recommended by the Fortress founder. I guess I need to buy one more Fortress

There, now... see how easy that was?



FWIW, one of the options a bit further down our own hurricane preparedness plan -- if moving the boat or haul-out won't work for some reason -- is to rush right out to buy (probably) two FX-80s. (Although maybe 55s would do.)

Then we'd do a Bahamian moor, with the existing SuperMAX in the middle and the two Fortress anchors on either side, all rodes led to the bow.

And then afterwards... if there IS an afterwards... sell the FXs.

-Chris

[Stumble]

Originally Posted by Panope

Sounds good, Greg. But i think the thing that is keeping folks awake at night is not so much ultimate holding power, but how the anchor handles re-set/rotating during the wind shifts.

I personally would sleep better with a moderate holding power anchor that re-sets perfectly, than with a super-duper high holding power anchor that cannot handle re-sets.

Steve

It would be easy enough to test the reset.

First just test the holding power in soft mud.
Next set the anchor and move the boat 120 degrees and measure how far it drags before resetting.

[Fortress]

Some thoughts:

• Much has been written about how an anchor performs during a wind or tidal shift.

However, if an anchor cannot handle the force, or load, from a straight line pull when it should perform optimally in common bottom types and wind conditions, then you might not find out how well the anchor performs during a wind or tidal shift.....the boat will already be set adrift beforehand.

• Soft mud (the original thought of this thread) is absolutely the Achilles' heel of most anchors, since it is possible that they will have as little as 10% of their holding capacity when compared to their performance in a harder soil.

• As per Steve / SV Panope's tests, let's say that you load up two anchors of comparable physical size and weight to 3,000 rpm during initial setting. Afterwards, you move the boat over the anchors at 3 knots on a 180° degree angle and pull on the anchors from that direction.

The anchor which performs the best during the initial setting is likely to perform the WORST in this scenario.

Why? Because the anchor which set the best (or deepest) initially has to dislodge from its deeper penetration into the bottom, flip over, and then shed the greater amount of sediment before it can then re-engage the bottom.

[Dockhead]

Originally Posted by Fortress

. . . Why? Because the anchor which set the best (or deepest) initially has to dislodge from its deeper penetration into the bottom, flip over, and then shed the greater amount of sediment before it can then re-engage the bottom.

Are you sure about that? I would have thought that an anchor which is set very deeply would merely rotate. Why would it need to come out of the seabed altogether?

Maybe Noelex has observed?

[Fortress]

Originally Posted by Dockhead

Are you sure about that? I would have thought that an anchor which is set very deeply would merely rotate. Why would it need to come out of the seabed altogether?

Keep in mind the direction of pull, it is coming from over and on top of the anchor, and pulling it to the upside down position.

[Dockhead]

Originally Posted by Fortress

Keep in mind the direction of pull, it is coming from over and on top of the anchor, and pulling it to the upside down position.

OK, I understand. But that would be a rare case in real life, wouldn't it? In most wind or tide shifts, the boat will rotate around, not just suddenly reverse direction, right?

[Fortress]

Originally Posted by Dockhead

OK, I understand. But that would be a rare case in real life, wouldn't it? In most wind or tide shifts, the boat will rotate around, not just suddenly reverse direction, right?

Definitely, and I am sure Steve will attest to that as well.

[AiniA]

I have only once had a situation where the wind shifted abruptly from one direction to the other (about 180°). It was in the North Channel of Lake Huron in an elongated anchorage that was open at both ends with hills on the other sides. Wind would blow one way for 10 to 30 minutes and then from the other. The boat sailed directly over the anchor (CQR as I remember) and pulled it out. I gave up resetting it after 3 or 4 goes and moved to a different spot.

[Panope]

Originally Posted by Dockhead

OK, I understand. But that would be a rare case in real life, wouldn't it? In most wind or tide shifts, the boat will rotate around, not just suddenly reverse direction, right?

Originally Posted by Fortress

Definitely, and I am sure Steve will attest to that as well.

Yes.

No question that my high speed, precision 180 re-set test (with resulting anchor "back flips") represents a unlikely scenario.

Steve

[Paul L]

Long time ago I cruised for a year with a large Danforth as the main anchor. There were many places where I used a Bahamian moor dual setup. These were mainly to deal with current, not so much wind. The big worry when on a single hook was not that the Danforth couldn't reset it self, it was that the rode could get caught up in the flukes as the wind/current rotated and trip the anchor leaving it in a position it could not reset.

[Don C L]

Keep in mind when the large flukes of a Fortress or Danforth are well-set they represent a HUGE resistance to any kind of turning a relatively small shank may want to exert. Flukes, doing their job I might say, will hold while the shank will likely bend. In straight line pull my relatively small Danforths, and I am sure Fortresses, are hard to beat, but I personally never ask my Danforths to turn a corner. I know many will find that a deal breaker when anchor shopping. Now 180 flip? the shank will be asked to pull the flukes out over the top and it might accomplish that, if not too deeply set, and then re-set, and as long as the rode did not foul on the stock on the way around, it might work out ok. Hey, I think those of us who rely on this kind of anchor are not ignorant of its weaknesses! Now, I have not tried a Fortress so its behavior may be superior to a Danforth in the turning department.

[pdenton]

On my bow. I have a 15 KG rocna and a 15 KG SuperMax, which was designed for the mud in the ICW. Call it up on its webpage and you will see immediately why it is the best mud anchor of all.
On my previous boat I had a Fortress which always let me down no matter what the substrate
pdenton

[Don C L]

Originally Posted by pdenton

On my previous boat I had a Fortress which always let me down no matter what the substrate
pdenton

Hmm odd, as much as I was not enthralled with the CQR (dragged once in a rough night), I would still never have made a claim like that about it. If an anchor always lets you down no matter what substrate, perhaps it was not necessarily the anchor to blame?

[Fortress]

Originally Posted by Don C L

Keep in mind when the large flukes of a Fortress or Danforth are well-set they represent a HUGE resistance to any kind of turning a relatively small shank may want to exert. Flukes, doing their job I might say, will hold while the shank will likely bend. In straight line pull my relatively small Danforths, and I am sure Fortresses, are hard to beat, but I personally never ask my Danforths to turn a corner. I know many will find that a deal breaker when anchor shopping. Now 180 flip? the shank will be asked to pull the flukes out over the top and it might accomplish that, if not too deeply set, and then re-set, and as long as the rode did not foul on the stock on the way around, it might work out ok. Hey, I think those of us who rely on this kind of anchor are not ignorant of its weaknesses! Now, I have not tried a Fortress so its behavior may be superior to a Danforth in the turning department.

Don, a fair comment and observation. In general, an anchor's movement while embedded in a seabed can be determined by its physical size, sharpness, structural strength, the soil shear strength (soil type), depth of penetration, and tension.

The Fortress has much sharper flukes than a Danforth and so it should slice through a sea bottom more efficiently, BUT it is also likely to bury deeper which might make turning more difficult during side loading.

As an example, when we lost an FX-37 during the Chesapeake Bay after it was calculated that the anchor had been buried 13 feet into the mud, I cannot imagine that this anchor was capable of any movement in the bottom with the sediment compressed hard against it and at that depth.

The anchor had basically become a mooring, reminding me of this recent comment about the FX-37 from Captain Dave Carraro, who has one of the fishing boats on the National Geographic TV show "Wicked Tuna":

"I can't compare Fortress to any other anchor after 40 years of fishing, it's lightweight, holds like a mooring and durable."