The inverted anchor drag

[simonfraser]

haha who started this 'best anchor thread?'

anyway:
'With a pivoting fluke anchor (ex: Danforth-type) there is no upside down position, so that is a clear advantage for this type of anchor.'

i have used one of those on my trimaran in mostly mud with some Stones. and they are the problem as in at least 10% of recoveries there is a pebble caught on the fluke and no way can it just flip over and reset

 

[vyv_cox]

I have posted several photos in the past illustrating very clearly that Rocna and Manson anchors rotate 180 degrees in sand on windshields without moving. The shank rotates around the flukes which remains fixed in position.

 

[Flica]

I have posted several photos in the past illustrating very clearly that Rocna and Manson anchors rotate 180 degrees in sand on windshields without moving. The shank rotates around the flukes which remains fixed in position.

I think. perhaps, that Jonathan is playing to the gallery, in making this contention.
Certainly, if you suddenly alter the direction of pull by c 180degrees there is a chance that some anchors will invert.
My experience is that when a reasonably slow change in the angle of pull takes place the anchor flukes shuffle round and the shank points in the new direction. Most photographic evidence seems to support this hypothesis.
This invesion seems to belong in the same subset as trying to set your anchor on top of your chain, possible but unlikely.

 

[Jamesuk]

I have posted several photos in the past illustrating very clearly that Rocna and Manson anchors rotate 180 degrees in sand on windshields without moving. The shank rotates around the flukes which remains fixed in position.

I'm saying, a horizontal pull in the opposite direction to the original anchor set which in the rare example inverts the anchor. Laying it on its back with a nice pull and without ability to rotate until it hits a rock

I would have thought the Delta stood less chance of setting in the inverted scenario than a Rocna thanks to the semi-circle

 

[Neeves]

I think. perhaps, that Jonathan is playing to the gallery, in making this contention.
Certainly, if you suddenly alter the direction of pull by c 180degrees there is a chance that some anchors will invert.
My experience is that when a reasonably slow change in the angle of pull takes place the anchor flukes shuffle round and the shank points in the new direction. Most photographic evidence seems to support this hypothesis.
This invesion seems to belong in the same subset as trying to set your anchor on top of your chain, possible but unlikely.

My tests were on the basis of a 180 degree tension change.

We have the situation on Australia's east coast. The afternoon seabreeze from the NE, 35 knots. SW change (front) comes though and the wind dies, swings through 180degrees in 30 minutes and develops to 35 knots. The intervening wind is not necessarily to strong enough to alter the set position determined by the sea breeze.

Breeze can be a bit of a misnomer.

Similar condition occurs in thunderstorms on America's east coast.

Jonathan

 

[GHA]

Lots of videos on here of severe resets

https://www.youtube.com/user/flygoodwin

 

[noelex]

I have posted several photos in the past illustrating very clearly that Rocna and Manson anchors rotate 180 degrees in sand on windshields without moving. The shank rotates around the flukes which remains fixed in position.

This has been my observation as well. Even with multiple 180° shifts the better anchors "shuffle". Providing they are set and in a reasonable substrate they remain in the same position other than the rotation.

I don't think it is impossible for a good anchor to break out but it I have never seen this happen with either my own Mantus or the previous Rocna, so it is very rare in real life.

 

[vyv_cox]

Thanks for understanding that when my phone wrote windshields I had typed windshifts!

 

[Neeves]

Thanks for understanding that when my phone wrote windshields I had typed windshifts!

You must have an iPhone

It most annoying that you need to correct the computer's errors as well as you own, even if my errors can be more numerous that the computer's.

Jonathan

 

[Pasarell]

I've bought a Fortress, still trying to understand how something this light will hold better than my trusty CQR?

I carried out an unplanned and wholly unscientific test a couple of weeks ago in the soft mud of Vlicho Bay in the Ionian.
Anchored using my main 25kg delta on 10mm chain in about 10kn of wind. Anchor well stuck in.
After tidying up had a snooze in the cockpit and woke to find some suspicious looking clouds downwind of me and, for once, had the foresight to get things ready to move. Sure enough the wind went through 180 degrees and increased to 25kn. All the boats in the bay went with it. Unfortunately I carried on going down wind as though I had no anchor down at all (30m of chain in 5m of water). Pulled it all up, narrowly avoiding the boat now downwind of me and moved off. When I had space I replaced the Delta with my Fortress FX 13 kedge then went back to the bay and anchored again. It quickly dug in but to be expected as it's soft mud and I settled down to wait. No wind overnight but in the morning it went back to the original direction so we all swang around again. This time I stayed put.
Unscientific as I said but certainly gave me confidence in the Fortress and another dent in confidence in Delta

 

[RichardS]

I carried out an unplanned and wholly unscientific test a couple of weeks ago in the soft mud of Vlicho Bay in the Ionian.
Anchored using my main 25kg delta on 10mm chain in about 10kn of wind. Anchor well stuck in.
After tidying up had a snooze in the cockpit and woke to find some suspicious looking clouds downwind of me and, for once, had the foresight to get things ready to move. Sure enough the wind went through 180 degrees and increased to 25kn. All the boats in the bay went with it. Unfortunately I carried on going down wind as though I had no anchor down at all (30m of chain in 5m of water). Pulled it all up, narrowly avoiding the boat now downwind of me and moved off. When I had space I replaced the Delta with my Fortress FX 13 kedge then went back to the bay and anchored again. It quickly dug in but to be expected as it's soft mud and I settled down to wait. No wind overnight but in the morning it went back to the original direction so we all swang around again. This time I stayed put.
Unscientific as I said but certainly gave me confidence in the Fortress and another dent in confidence in Delta

The first time I dragged in soft mud with the Delta was the last as I immediately ordered the Rocna.

Plough anchors .... they do what it says on the tin!

Richard

 

[Neeves]

Naw - all wrong, you are living in some form of parallel universe. We are continually told, by experts. Fortress will not take a change of wind direction. Please wake up and come back to reality.

Jonathan

 

[vyv_cox]

The first time I dragged in soft mud with the Delta was the last as I immediately ordered the Rocna.

Plough anchors .... they do what it says on the tin!

Richard

Exactly the same with me, and also in Vliho Bay. The wind was considerably stronger than 25 knots and my Delta, which I had been perfectly happy with for many years, failed to hold in 3 attempts. Eventually I reversed into the mud on the west side and tied to two trees. My Rocna was ordered soon afterwards.

 

[Jamesuk]

I carried out an unplanned and wholly unscientific test a couple of weeks ago in the soft mud of Vlicho Bay in the Ionian.
Anchored using my main 25kg delta on 10mm chain in about 10kn of wind. Anchor well stuck in.
After tidying up had a snooze in the cockpit and woke to find some suspicious looking clouds downwind of me and, for once, had the foresight to get things ready to move. Sure enough the wind went through 180 degrees and increased to 25kn. All the boats in the bay went with it. Unfortunately I carried on going down wind as though I had no anchor down at all (30m of chain in 5m of water). Pulled it all up, narrowly avoiding the boat now downwind of me and moved off. When I had space I replaced the Delta with my Fortress FX 13 kedge then went back to the bay and anchored again. It quickly dug in but to be expected as it's soft mud and I settled down to wait. No wind overnight but in the morning it went back to the original direction so we all swang around again. This time I stayed put.
Unscientific as I said but certainly gave me confidence in the Fortress and another dent in confidence in Delta

Sounds exactly the same, I'd suggest the anchor inverted and just dragged with the plough side facing the boat and not the seabed.

So the anchor inverts in sand/mud/soft stuff and because it is inverted will never dig in until it rights by some luck of having a big stone to help push it over

Thanks for your experience, instead of ordering a new anchor better to have an electronic anchor watch for wind direction change and carry on.

If ordering a new boat a good time to change.

 

[NormanS]

Sounds exactly the same, I'd suggest the anchor inverted and just dragged with the plough side facing the boat and not the seabed.

So the anchor inverts in sand/mud/soft stuff and because it is inverted will never dig in until it rights by some luck of having a big stone to help push it over

Thanks for your experience, instead of ordering a new anchor better to have an electronic anchor watch for wind direction change and carry on.

If ordering a new boat a good time to change.

Sorry, I don't get that. When you drop an anchor, you have no way of ensuring that it lands "the right way up". That's why, for instance, Rocnas and others have roll bars, so that they rotate to the right way. Why should a disturbed anchor not do exactly the same?

 

[thinwater]

I was doing some anchor testing for an article (holding capacity vs. setting time and procedure in soft mud) using a 35-pound Manson Supreme. I set an FX-16 off the bow and used it to drag the 35-pound scoop, which weighed 3x as much. The lightweight Fortress went deep, down into firm mud, and would hold a ton... literally.

It's more about projected area than mass.

 

[Jamesuk]

Sorry, I don't get that. When you drop an anchor, you have no way of ensuring that it lands "the right way up". That's why, for instance, Rocnas and others have roll bars, so that they rotate to the right way. Why should a disturbed anchor not do exactly the same?

The magic of sailing. In 1000 drops this happens once.

 

[Neeves]

But if the seabed is very soft the roll bar will simply sink into the seabed. Same with a Delta shank - it needs the shank to rest on something firm.

So in soft sand if the anchor lands upside down the roll bar (or shank) can sink into the mud and it will not self right.

Go and find some very soft sand, soft mud is mucky to work with, and try 'it'. I can assure you 'it' works (or if 'it' is the anchor rather 'it' being the effect the anchor will not work). I've watched it happen.

If you go an read the Fortress Chesapeake tests this effect was considered as the possible reason for the very poor results for most anchors - they did not self right and simply dragged upside down and perfomed like ballast (for which there is a thread somewhere currently).

Soft mud, quite common, soft sand less so (I think) - but I watched it in soft sand.

So in soft mud use a Fortress, or Danforth

Jonathan

 

[NormanS]

Yes, possibly if you anchor in porridge.

But the suggestion is that an anchor which performs satisfactorily initially, doesn't re-set after being disturbed. OK, if it's choked up with mud, weed etc, but if it worked when first dropped, why not now?

 

[Neeves]

Because first time it was dropped it landed right way up and did not need to self right.

During the Fortress Cheasapeake tests they could not understand the poor performance of anchors that would have been expected to give at least some hold - these same anchors were developing hold no better than a mushroom weight. They had no diver, and it was mud, and they guessed that maybe the anchors were being dropped and landing upside down and simply 'skating' through the mud. They added a float to one of the anchors to encourage it to land right way up and the anchor developed some hold - suggesting the idea of landing upside down had some merit - but they could never prove the hypothesis. Interestingly, though it did not form part of the debate, the hollow shanked Ultra developed much better hold than the Spade, whose shank is 'open' and thus not a float. Mantus is hydrodynamic - as long as the 'setting' vessel is moving backward (and the anchor is deployed off the bow) Mantus will always arrive at the seabed and land right way up - in the Chesapeake tests the Mantus was the best of a poor bunch. Of course if it then somersaulted and lands on its back - it will not self right, even though it did, in the tests, developed some hold - they did not try somersaulting.

Soft mud occurs in many places, usually where oysters are found. So the idea of an anchor developing some hold and later not resetting - might be unusual - but definitely possible.


Interestingly the only company to test anchors in soft mud is Fortress, whose anchor stands head and shoulders above anything else (which is presumably one reason they chose that bottom type). But other anchor makers have not tried to refute the tests, nor make their own tests in soft mud (I wonder why?)

Jonathan