Dragging of anchors

[JumbleDuck]

You have the magic touch! Respect. I suffered more than 10 years with a CQR, and could never get the damn thing to set properly, not even in sand.

Very strange. Was it a genuine CQR or a generic plough?

 

[Robin]

No experience with bending but a soft shackle is so superior in every way to a hook of whatever design I have no clue why anyone uses a chain hook at all.

We have used a cast, or maybe it is forged, S/S chain hook for many years bought in Europe, without it causing problems by falling off, it is cheap and reliable technology easy to deploy and remove. Soft shackles sound useful but I have never tried them and when I did look seemed quite expensive too, plus as a simpleton I'm not absolutely sure how they are deployed on a snubber line to chain connection, always ready to be educated however - pictures help!.

 

[Neeves]

I found trying to attach a soft shackle to 8mm chain difficult, its also more difficult to remove, a chain hook falls off or can be taken off, one handed, very quickly.

Remember that imperial chain, ostensibly the same size as a metric chain, 5/16th" = 8mm and 3/8th" = 10mm etc, has a much larger link size (or its much larger when trying to fiddle about with a soft shackle).

Jonathan

 

[sailaboutvic]

Apologize Jonathan just going to drift this thread a bit.
I don't want to start another anchoring thread , there too many on the go already.

Good start to the week.
We had a heavy yacht anchor near us, but a good distance apart, nothing to worry about or so I thought.
Wind blow all day from a different direction each time we were well apart.

Overnight wind drops and everyone were facing all over the place, the other yacht must have ended up well in front of his anchor close by, normally This isn't a problem has the wind pick up and everyone swings and all is well.
But Mr Murthy had other plans.
07.30 We were hit by a thunderstorm and the wind when from nothing to 25kts if not more in seconds,
I got into the cockpit just it time to see us stretching out on our chain at speed about to be T boned by the heavier yacht which hasn't started to move.
Lucky his bowsprit caught our guard wires given me time to push him off.
Damages two bend stanchion,
A warning to others who think anchoring too close will only incur a bump and their fenders will come to their rescue Has it been written on another thread.
Although he anchored after us I can't really blame him for the damages, he did anchor what I would have considered a safe distance,
Act of God, I suppose, so we will have to stand the cost of the damage.
It could have been a lot worse.
I always consider what type of vessel I anchored next to. And how they are going to behave.
But has you can see even after all precautions are taken, things can still go very bad.

 

[Neeves]

SA Vic,

Really tough luck. Lucky you were up and about. But as you say - could have been much worse.

And there is no need to apologise about thread drift - perfectly acceptable.

Jonathan

 

[vyv_cox]

For those that use short snubbers (so you are simply moving the load from the windlass to a strong point and you stop chain rattle on the bow roller) and even those that use long snubbers - have you ever damaged a chain hook. I recall someone mentioned, on another thread, that they had bent a Witchard hook, not the pin but the hook. Is this common (to bend the hook). More likely on a short snubber, say 6" or less.

If you bend a hook then you are imposing the same 'load' on the anchor (so it might be likely to drag?? on the chain, so it might stretch and also loading your strong point. Any experiences? and if so what heppened and how

Jonathan

I bent a wire snubber hook, the upper one shown here, but in exceptional conditions. We were stern-to in the Sporades at a port renowned for poor shelter in NE winds. The snubber was fitted to take load off the windlass but not particularly to provide snubbing, so was quite short. In early morning the wind began to blow in, creating waves, in which we were surging quite violently, enough to tear two fairleads out. After a time of enduring this the wire of the snubber hook bent, the boat surged backwards and the aft platform was punched through the transom when we hit the wall.

I replaced the old hook with a forged one, shown below.

On soft shackles, I can get a 2 ton one through a link of an 8 mm chain but not a 5 ton one. Even with the 2 ton one, possibly marginal on strength, it is a real fiddle to do, using two hands that is extremely uncomfortable on my foredeck, whereas the hook is quick and easy with one hand. When retrieving I only need to wind in half a metre of chain to get the hook to fall off, when the snubber can be coiled and stowed. For me there is absolutely no way that a soft shackle is better.

 

[Neeves]

Both Noelex and Vyv have reported on catching a stone or rock in the fluke of their anchor. In neither case did the offending item cause the anchor to drag as in both cases the rock was identified as a deterrent to setting (and the errant rock was removed to allow normal setting). We all catch odd items with out anchors, we caught a 4.5kg propane cylinder in the toe of our anchor once and many can quote other items (supermarket trolleys and discarded/lost lobster pots are another).

But ignoring discarded or lost manmade items - has anyone caught a rock in their anchor. I ask as it is not something that I recall being noted in the past (though submerged logs and trees are more common). I need to correct that statement - I have a friend who was skippering an Oz landing craft near Cape York and he caught a 'anchor sized' lump of dead coral in a 70kg, genuine, Bruce.

edit - we do anchor in a couple of anchorages with rocks, so not all anchorages in Australia are soft sand. Areas of Bramble Cove in Tasmania is 2" of sand (presumably it varies) over an indeterminate depth of 3" rock pieces. Other parts of Bramble are mud. Jamieson Bay, off Flinders Island, has parts of the bay with rocks of sizes between about 3" and 6". Both bays make good anchorages and we have not caught a rock in the fluke, yet. Close edit

Jonathan

 

[geem]

Both Noelex and Vyv have reported on catching a stone or rock in the fluke of their anchor. In neither case did the offending item cause the anchor to drag as in both cases the rock was identified as a deterrent to setting (and the errant rock was removed to allow normal setting). We all catch odd items with out anchors, we caught a 4.5kg propane cylinder in the toe of our anchor once and many can quote other items (supermarket trolleys and discarded/lost lobster pots are another).

But ignoring discarded or lost manmade items - has anyone caught a rock in their anchor. I ask as it is not something that I recall being noted in the past (though submerged logs and trees are more common).

Jonathan

Years ago when we had a Bruce anchor we caught a rock. We couldn't work out why we were dragging until we pulled the anchor up. A perfect round rock stuck in the flukes. It took some getting out.

 

[Neeves]

I bent a wire snubber hook, the upper one shown here, but in exceptional conditions. We were stern-to in the Sporades at a port renowned for poor shelter in NE winds. The snubber was fitted to take load off the windlass but not particularly to provide snubbing, so was quite short. In early morning the wind began to blow in, creating waves, in which we were surging quite violently, enough to tear two fairleads out. After a time of enduring this the wire of the snubber hook bent, the boat surged backwards and the aft platform was punched through the transom when we hit the wall.QUOTE]

Vyv,

Did the wire snubber have a WLL giving an idea of what sort of loads were needed to bend the wire.

We have a cast version, a claw, of the wire version you were using. We use it to secure the anchor on the bow roller (we also have a steel pin through a chain link). The claw looks pretty robust and is rated as a 5/16th" G70 but no use for a snubber as it lacks security (it could fall off). We are now using a chain hook not dissimilar to the one you show in your image (it might be the same).

Jonathan

 

[NormanS]

You have the magic touch! Respect. I suffered more than 10 years with a CQR, and could never get the damn thing to set properly, not even in sand.

Astonishing. Generations of ordinary people have used CQR anchors successfully and without incident.
Astonishing that If you could "never get the damn thing to set properly", in 10 years, did it not occur to you that either there was a fault with your particular anchor, or that maybe you were not using it correctly.
Astonishing that you persisted without success for 10 years.

 

[vyv_cox]

Jonathan,

No, it was just a cheap thing, don't remember where I bought it. Cannot really blame it for bending in the circumstances.

Vyv

 

[Dockhead]

Very strange. Was it a genuine CQR or a generic plough?

It was a gen-u-wine forged, very expensive, CQR.

But the blame is not all the anchor's -- it was my father's boat, and he had totally crap anchoring technique, which he passed on to me, which was overcome only gradually, with time and experience.

That being said, though, that anchor was very hard to set, objectively speaking.

 

[NormanS]

Most of the people contributing to the thread anchor a lot, some do not use snubbers (at all) some use short snubbers and some use snubbers that provide some real elasticity.

For those that use short snubbers (so you are simply moving the load from the windlass to a strong point and you stop chain rattle on the bow roller) and even those that use long snubbers - have you ever damaged a chain hook. I recall someone mentioned, on another thread, that they had bent a Witchard hook, not the pin but the hook. Is this common (to bend the hook). More likely on a short snubber, say 6" or less.

If you bend a hook then you are imposing the same 'load' on the anchor (so it might be likely to drag?? on the chain, so it might stretch and also loading your strong point. Any experiences? and if so what heppened and how

Jonathan

For normal day to day anchoring, I don't bother with a snubber. With 10mm chain, which incidentally is not as you say equivalent to 3/8", but quite a bit bigger and heavier, I find that the catenary of the chain removes any shock loading.
When I do rig a snubber, I use a chain hook. The hook was made with a piece of 5mm stainless steel plate, a hacksaw, a drill, and a file. It's just a hook shape with a slot to fit the chain, and a hole for a shackle. I am a PBO.

 

[Dockhead]

Astonishing. Generations of ordinary people have used CQR anchors successfully and without incident.
Astonishing that If you could "never get the damn thing to set properly", in 10 years, did it not occur to you that either there was a fault with your particular anchor, or that maybe you were not using it correctly.
Astonishing that you persisted without success for 10 years.

So much astonishment! I'll be!

As I posted above, poor technique was the main culprit, but not the only one.

I hyperbolized maybe a little by saying I "never" could get it set properly -- not "never". The first years, any good sets were purely accidental. After that, I gradually learned how to work the anchor into the seabed -- over the objections of my Father, who thought that backing down on the anchor might "pull it out!" and delay his cocktail hour. But for years, at least 10, we did drag often -- and that was par for the course in those days ('80's and '90's) -- everybody dragged from time to time. We would drag anchor on average once on every cruise. We would sleep with one eye open and just get up and re-anchor when it happened. My technique gradually improved, and I did pull that anchor out backing down on it, and would go around again, often several times, until some rough approximation of a set resulted.

I do not think that this was at all an atypical experience. Anchor dragging stories formed a large part of the conversation whenever we met with other sailors. At the end of the '90's, my Father bought a Spade anchor, and the difference was dramatic. Even he, who continued to refuse to back down on the anchor for fear of "pulling it out", started to get good results. And I was suddenly getting the anchor well set first time, every time. So technique was not the only factor at play.

Since then we have used various anchors including a 55kg Rocna, Deltas, Claws, and various others, all of which were far easier to set than the old CQR.

The last time I dragged an anchor was on a chartered catamaran in the Windward Islands some 12 (I guess) years ago. Some years ago I stopped being satisfied unless the anchor held for several minutes at full power in astern. GPS receivers became more accurate and at some point I could see whether the anchor was creeping or not when backing down on it. So gradually both technique and the anchors themselves and other tools have combined to make anchoring much more secure than it used to be. I'll bet I'm not the only sailor with such a history.

 

[NormanS]

Re picking up rocks. We now use a (genuine ) Bruce, and have picked up rocks three times. It wasn't a big deal, as each time it was immediately apparent by the lack of grip, and easily rectified by tripping the anchor.
One of the times was a complete mystery, as it was in a sandy bay, where there shouldn't have been any stones or rocks. The other two occasions were when anchoring well "off piste", where the bottom could have been anything. Inspite of its occasional tendency to harvest rocks, I have great confidence in the anchor.

 

[noelex]

Both Noelex and Vyv have reported on catching a stone or rock in the fluke of their anchor. In neither case did the offending item cause the anchor to drag as in both cases the rock was identified as a deterrent to setting (and the errant rock was removed to allow normal setting). We all catch odd items with out anchors, we caught a 4.5kg propane cylinder in the toe of our anchor once and many can quote other items (supermarket trolleys and discarded/lost lobster pots are another).

But ignoring discarded or lost manmade items - has anyone caught a rock in their anchor. I ask as it is not something that I recall being noted in the past (though submerged logs and trees are more common). I need to correct that statement - I have a friend who was skippering an Oz landing craft near Cape York and he caught a 'anchor sized' lump of dead coral in a 70kg, genuine, Bruce.

edit - we do anchor in a couple of anchorages with rocks, so not all anchorages in Australia are soft sand.

Rock is always of concern, and as Jonathan has mentioned, it occurs worldwide.

There are many types of rock. Large boulders like the ones where I photographed this CQR can be a problem. The anchor can appear to grip quite well, but with a change in direction of pull the holding can drop to close to zero. It is best avoided if you can:

Gravel, or fist sized rocks are less of a concern.
This is a photo of my Mantus in this type of substrate:

While anchors can set and perform well in this sort of substrate, there is always some concern there are larger boulders below the surface. If the fluke hits one of these boulders the anchor cannot penetrate and the burial of the anchor will be disrupted. This is not uncommon in rocky ground.

The best defence is an anchor that sets and digs deeper very quickly. This is also true for man made debris like the propane cylinder that Jonathan mentioned. An anchor that routinely takes 5-7m to set like many of the convex plough anchors, is more likely to pick up this sort of debris. Designs that typically set in metre or less have a big advantage in reducing the risk of these problems.

A thin sand layer over smooth rock is another problem substrate. The only real defence seems to be a big, preferably concave anchor that can scoop enough sand in front of the fluke to provide some holding.

BTW. I don't remember the incident you are referring too. Perhaps I am misunderstanding or maybe it was someone else?

 

[Neeves]

Noelex,

You are a bit broad brush with your definitions. Some convex plough type (as you describe them) can set in a very short length, less than a shank length, and if correctly sized can dive such that all of the anchor is buried within that shank length - which is why they are not very photogenic - you cannot see them. They therefore meet your other definition - they set and dig deeply, quickly.

I had thought you did not like anchors that scooped sand in front of the fluke? I note some contradiction, perhaps.

Jonathan

 

[Neeves]

Noelex

I note your quote, above, but cannot quite reconcile it with the almost contradictory post you made previously. In the post above you seem to say that convex plough anchors do not work well but in the quote you made earlier on another forum you say they can work well??

I also wonder if you have actually seen a cross section of modern convex anchors working in hard sand to be able to make the broad statements of which you are fond.

Quote from Noelex, a few weeks ago on Cruisers Forum.

This was a Delta in 5m @ 6:1.

It was anchored close to us, but the substrate is quite different. It was mainly fist sized rocks with a few larger boulders thrown in for fun. This is not a great set, but considering the nature of the bottom I thought the anchor was doing very well. The fist sized rocks were tough to push aside and its final set does not look that different to what this anchor achieves in sand.

This is only one example. Performance in this sort of substrate is very hard to evaluate, but I have noted before that fist sized rocks is one substrate where convex plow anchors seem to perform relatively well.

The relatively thick profile in the fluke of convex plow anchors, which is necessary to contain the ballast, is at a disadvantage trying to penetrate hard sand and weed, but I suspect it is a good shape for pushing aside the fist sized rocks in this sort of substrate. The main concern is long setting distance which means a greater risk of encountering a larger boulder and tripping out.

Note there are some clouds of sand in the photo. These generally mean the anchor was moving, but in this case once the surface was scraped away, the underlying sand tended to billow out and float around. This anchor was not slowly dragging.

end quote

Jonathan

 

[Neeves]

Maybe this will remind you

quote

A new anchorage and a very interesting result.

The Mantus held full reverse as per normal, but rather than an immediate instant dig in, it gave a slight, but a very uncharacteristic skip of a couple of feet when reverse power was applied.

The Mantus has hit a large subsurface rock (it looks like two rocks in the photo, but it is actually a large single rock). Consequently the anchor has taken about 50% longer than normal to set. You can also see a lot of piling up of the substrate. Both of these characteristics indicate the anchor is struggling to penetrate the bottom properly. Even excellent anchors are defeated by rock.

Many of my underwater photos have shown this type of behaviour from other anchor designs simply in hard sand. This piling up rather than digging in is a classic sign of an anchor not performing well.

Hidden hazards (both natural and unfortunately man made garbage) are surprisingly common. It is a great help to have an anchor that normally sets in a shank length rather than a design that takes many metres to start digging in. This greatly reduces the chance of hitting these sort of obstructions. The Mantus is great in this regard, but as you can see this reduces, but does not eliminate risk.

Even with the best anchor equipment and technique don't forget an anchor alarm. An anchor can be disrupted by a rock, an old towel, discarded spinnaker, tyre or tree (don't ask ). In some circumstances it can hold full setting force, but not be performing normally.

In this case the anchor looks to have started penetrating the sand under the rock and with a forecast of light winds we felt a re-drop was not needed. Let's hope we are right .

unquote

Jonathan

 

[Neeves]

Its a bit early to draw any conclusions to the question of rocks caught in anchors but the evidence so far seems to suggest that concave anchors catch rocks but convex, according to Noelex - see post above, have the ability to shovel them aside. However I think this might need some tuning as I have not heard of Spade/Ultras catching rocks so maybe all concave are not created equal.

edit It also seems that modern and pre modern concave designs might have an equal propensity to catch rocks - from current, limited, posts on the topic. close edit

Jonathan