Photos of Anchors Setting

[colemj]

Originally Posted by DefinitelyMe

Those of you who have these stainless swivels and also have old chain, take a look at the 2 or 3 links of chain closest to the swivel. That corrosion is not due to mechanical wear.

We have a stainless swivel on our galvanized anchor with galvanized chain. We are anchored almost full time.

We do not have any of the issues you speak of. There is a bit more corrosion around our shank, but it is mechanical wear (the wear profile exactly fits that of the swivel cheeks - like is also shown in the picture you reference). Likewise, there is more corrosion on the tip of the fluke - which is also mechanical wear, since it is not connected to stainless at all.

The links closest to, and attached to, our swivel show no problems with galvanic corrosion. I cut the last link off every couple of years just for fun, but it really isn't any different from the others.

It has been this way for the past 7yrs of full-time cruising and the previous 5yrs of weekend/vacation cruising.

Mark

[noelex 77]

This was a Plow (a CQR copy)

It was not doing well. It had a long, long drag mark (25m?). I could not get this all in the photo.

As you can see, at the end of this it has dug in very poorly. Interestingly it was upright. Normally the Plow/CQR falls on its side then takes a long time to rotate upright. The shank and hinge is very heavy.

This one was sitting upright before it had buried.

[noelex 77]

This was a Bruce.

It was on its side, but had been subject to little force (there is only a very short drag mark) this stage so it does not tell us much about how the anchor is performing.

[noelex 77]

A new anchorage. Yeah, I am slowly catching up with photos . 6.5m @ 5:1

We were not at the previous anchorage as long as the posts suggest. It is just that in busier anchorages we can photograph more anchors than I can post so I have fallen behind.

The Mantus has done a good job again. As usual, it has set very quickly and is well buried in gravelly sand, although there is little more heaping up and list than would be normal.

The concern is the numerous scattered rocks visible. Some of them are quite large. When you see rocks like this there are invariably similar rocks under the substrate.

An anchor that sets very rapidly like the Mantus has a significant advantage. No anchor can penetrate solid rock. If the tip hits a large subsurface rock like the one that can be seen on the bottom right of the second photo, it will trip and break out. This process is repeated each time a new obstruction is encountered. Anchors that routinely take 5-7m or longer to set have a tough time. The risk of catching a large rock at some point in this sort of setting distance is high.

Even when set nicely there are potential problems. To dig in deeper the anchor will move back. Generally this is proportional to the setting distance. Anchors that take a long distance to set will move back a long way as they dig in deeper when exposed to stronger wind.

The concave rollbar anchors are great in this regard. They will move back mere inches as they dig in. However, even this small movement caries some risk that the anchor tip can hit a large rock so substrates like this are better avoided.

[Prairie Chicken]

Even when set nicely there are potential problems. To dig in deeper the anchor will move back. Generally this is proportional to the setting distance. Anchors that take a long distance to set will move back a long way as they dig in deeper when exposed to stronger wind.

Noelex, I'm having trouble understanding this terminology. I understand the setting distance as the distance the anchor moves from the point it touches the bottom, moving in the same direction as the boat, until it, and the boat, stops. Logical. But moving backward has me scratching my head. Do you mean it continues to move toward the shank & boat, or the other direction, backward, and away from the boat?

Or maybe I just need another cuppa this morning?

[noelex 77]

Originally Posted by Prairie Chicken

Noelex, I'm having trouble understanding this terminology. I understand the setting distance as the distance the anchor moves from the point it touches the bottom, moving in the same direction as the boat, until it, and the boat, stops. Logical. But moving backward has me scratching my head. Do you mean it continues to move toward the shank & boat, or the other direction, backward, and away from the boat?

Or maybe I just need another cuppa this morning?

Yes, it is a bit confusing . There are really no proper terms to describe what is happening. Perhaps because there have been very few photos or videos of anchors in action, there is no uniform vocabulary.

We could call the movement of the anchor downwind towards the boat as "backwards" or "forward". "Backwards" seems more logical to me only because if the anchor is dragging we say the boat is moving "backwards" a boat dragging backwards while the anchor is moving "forward" does not sound right to me.

There are other problems with terminology.

If I describe a typical "set" it makes the problem clearer.

If we come in an anchorage and drop our anchor, it is at first just sitting on the bottom totally unset. We then apply some force on the anchor via the engine and/or wind and current.

From its drop point the anchor moves towards the boat when some force is applied. As the anchor digs in it will (hopefully) come to a stop. We could also say the anchor is dragging because both the anchor and boat are moving. However I think it more appropriate to call this the "setting distance".

If the direction of pull remains unchanged and the force on the anchor stays less than the setting force (in other words if wind stays less than 25-30 knots) the anchor will just sit unchanged. However if the wind picks up to say 40 knots the anchor has to dig down deeper to resist the stronger force. This can be seen in some of the photos with the anchor more buried as it is exposed to more wind.

If the anchor is doing its job we think of the anchor "holding" during this phase. However, the reality is that as anchor digs in deeper it also has to move backwards (towards the boat). Remarkably anchors like the Mantus (and my Rocna before it) will dig in deeper while moving back only slightly (inches) but they still move. Before the camea I often dropped stones as reference points so I could see exactly how much the anchor had moved during this phase.

There is no term for this movement, I am open to suggestions.

Here is a recent Rocna photo that illustrates how the anchor always moves as it digs in deeper. This anchor was not set with much force initially, but it still illustrates the principal.






Excellent anchors like the Mantus and Rocna have a very short setting distance (2-4 feet) In this distance (the setting distance) the anchor has dug in and buried enough to hold full reverse (or the equivalent of 25-30 knots of wind).

When exposed to even very strong wind will move backwards only inches as they dig in deeper. However, many designs of anchors have a much longer setting distance in the same substrate. They also move "back" (towards the boat) much further as they they are exposed to stronger wind.

Anchors that set rapidly invariably move back very little as they dig in deeper in response to stronger wind. Anchors that take a long distance to set will move back a long way before they can dig in deep enough to resist a stronger force.

A longer movement back is a significant drawback. If you have anchor that takes a long distance to do this even if you set it carefully with full reverse you need confidence that the substrate is clear of rocks, debris weed etc if there is a possibility of stronger wind. Even if you are confident the anchor is capable of holding this force you also need confidence in the uniformity of the substrate. Even seemingly uniform substrates have an alarming amount of debris that will upset an anchor. There is also a much greater risk of snagging under a rock, old mooring chain or cable.

So an ideal anchor not only has very high holding power it attains this high holding power very quickly while only moving back a short distance. This is not normally assessd and reported by traditional anchor tests. I hope the photographs show very clearly which type of anchors set quickly and those that take much much longer.

[noelex 77]

The Mantus set well, but the isolated rocks gave some hint that this was not an idea bottom. It rapidly became clear that there were some awful patches of substrate in this anchorage.

For me, the take home message is: ignore the anchor sizing tables and get the biggest anchor you can comfortably manage. You never know when you are going to encounter this sort of terrain.

The other message is always use an anchor alarm. In this sort of bottom you could drag at a quite low windspeed.

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.

[hoppy]

As well as having an anchor alarm set, I think it is very important to have your track displayed on your GPS.

This is my track from 27 hours swinging in 30 to 45 knots wind whilst I had no propeller. Watching the track in these conditions told me that I was not going anywhere and could more comfortably take a taxi to town to get a part made.

The track can help you see that you are drifting well before the alarm warns you 😃




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[redsky49]

"I used my previous Rocna for 5 years and it was very good in weed. I hopeful that the Mantus will be even better. The Mantus blade is long and thin. It has the best blade shape (in theory) of any of the modern anchors for penetrating past the weed roots"

I am curious about this. On the one hand, my suspicion is that all the concave anchors - Manson, Mantus, Rocna, and perhaps Bugel and others - behave relatively similar, the differences being primarily marketing, i.e., being able to be disassembled, etc. But seeing the difference in reported performance between the original Bruce and the Lewmar Claw may indicate that subtle differences are critical.

If you still have the Rocna aboard, and are anchoring in similar areas to that which you used the Mantus, would it be possible to return to the Rocna and see if your prior opinions still hold true? Sort of an A-B-A comparison.

With all the followers you have generated with this thread, it would also be interesting if you were to test and examine the performance of some of the competitors to the concave/roll bar style anchors. This also would give opportunity to your detractors (see bigger is better anchor thread) to put up or shut up. That is assuming they have the confidence in their anchor that Mantus has in theirs.

[Lure_]

noelex, mermaid and other contributers: a big thank you for your enormous effort!

I am new sailboat owner that was in search for secondary/backup anchor to my Delta 25 kg. I am glad I have found this great thread two weeks ago. I am reading it every day for couple of hours a day and today I have finally reached to last page! So much useful information and great photos!

As a consequence, I now know that I am in the process of buying new primary anchor, making my existing Delta as backup.
I know it will be either Mantus or Rocna, but need to evaluate sizes further (will probably make cardboard models).

I have however one question/request for noelex: could you once not fully set the Mantus, to replicate the setting style of your friend from post #1849 (with Rocna and how it progressed in couple of hours)? We all know that you can set your anchor perfectly, but seeing how Mantus behave if only partially set would be great information to compare it to Rocna.
It is actually similar request as from redsky49: more head to head comparison of Rocna and Mantus on same/similar setup.

[malbert73]

Having had a mantus first on my old boat and now a rocna, I think you would be splitting hairs to choose. I think the rocna shank is heavier and stronger relative to overall anchor weight. Mantus puts more weight in fluke area which is larger for same weight anchor. I bought rocna only because hoop on same sized Mantus is huge and didn't fit well


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[noelex 77]

Originally Posted by redsky49

On the one hand, my suspicion is that all the concave anchors - Manson, Mantus, Rocna, and perhaps Bugel and others - behave relatively similar, the differences being primarily marketing, i.e., being able to be disassembled, etc. But seeing the difference in reported performance between the original Bruce and the Lewmar Claw may indicate that subtle differences are critical.

If you still have the Rocna aboard, and are anchoring in similar areas to that which you used the Mantus, would it be possible to return to the Rocna and see if your prior opinions still hold true? Sort of an A-B-A comparison.

With all the followers you have generated with this thread, it would also be interesting if you were to test and examine the performance of some of the competitors to the concave/roll bar style anchors. This also would give opportunity to your detractors (see bigger is better anchor thread) to put up or shut up. That is assuming they have the confidence in their anchor that Mantus has in theirs.

I agree with much of what you say. In my view, anchors of a similar design, as long as the geometry and balance are correct, will perform in a similar way underwater. Anchors are simple lumps of metal. If you look at the photos of the concave roll bar anchors (Mantus, Rocna and Manson Supreme) they share very many similar properties.

The multitude of convex plow anchors behave very differently to concave roll bar anchors, but once again if you group together the photos of the different convex plow anchors that I have shown, there are a lot of similarities.

The same is true of other general classification of anchor designs although some models, such as for example the XYZ, do not fit into any group.

That does not mean the performance within the same category is identical. Refinements as simple as sharpening the leading edges can, and do, produce improvements.

There are also cases where anchors have poor geometry or balance. This is the problem with some of the Claw (Bruce copies). The twist in the outer flukes is important to level out the anchor. Some copies are terrible with totally the wrong shape. An anchor that is badly made with incorrect geometry or balance will always do poorly.

I hope by looking at the photographs the large differences between say a Delta and a Rocna are very easy to see. There are lots of phototographs but you only need to look at a few examples to see these anchors are performing at a very different level.

Picking the difference between anchors that are close in performance, say between the Mantus and the Rocna, is more challenging. They are both excellent anchors and you need to look at lot of examples and factor in the variables to pick a difference, but I still think this is possible.

The ideal, as you point out, would be to swap the anchors regularly, but moving large anchors is not easy and to secure the anchor properly needs some changes to bow roller set up. Unfortunately, this is just not practical.

All the concave roll bar anchors (Mantus, Rocna and Manson Supreme) are great and very similar. Any one is an excellent choice. Having used both the Mantus and the Rocna, my view is that the Mantus does most things just slightly better. The main drawback is the Mantus is wider and longer so there will be some bow rollers where it may not fit.

I hope to use and photograph different anchors in the future. My long term evaluation is very different to normal anchor tests and I hope it is valuable. As the number of examples build, I think the more subtle differences will become clearer.

Please note the above are just my opinion. I would encourage people to look at the photographs and make up their own mind.

[noelex 77]

Originally Posted by Lure_

noelex, mermaid and other contributers: a big thank you for your enormous effort!

I am new sailboat owner that was in search for secondary/backup anchor to my Delta 25 kg. I am glad I have found this great thread two weeks ago. I am reading it every day for couple of hours a day and today I have finally reached to last page! So much useful information and great photos!

As a consequence, I now know that I am in the process of buying new primary anchor, making my existing Delta as backup.
I know it will be either Mantus or Rocna, but need to evaluate sizes further (will probably make cardboard models).

I have however one question/request for noelex: could you once not fully set the Mantus, to replicate the setting style of your friend from post #1849 (with Rocna and how it progressed in couple of hours)? We all know that you can set your anchor perfectly, but seeing how Mantus behave if only partially set would be great information to compare it to Rocna.
It is actually similar request as from redsky49: more head to head comparison of Rocna and Mantus on same/similar setup.

Hi Lure
Thanks for the kind words. Reading through the entire thread is quite a feat . I think your plan to get the best bow anchor is a good one.

I can understand your request. I am reluctant to not set the anchor though, as I consider this poor practice, but I was forced to do this in post #524 when I managed to get our trolling line around the prop, disabling the engine. This was set in 15 knots of wind, but the sand was quite soft. Nevertheless, you can see a nearby Delta doing much less well in post #543.

The Mantus set with no engine:



Any anchor that is just dropped on the bottom with no wind force will just sit on the bottom and look just like several anchors I have shown in this thread. Anchors need some force to dig in. The Rocna in post# 1849 did a reasonably good job.

The initial Rocna photo in post showed almost no drag mark, which indicates very little setting force. The Mantus or any other anchor would not have looked any different. The second photo was slightly disappointing for a top class anchor. It has moved back a reasonable way and was not dug in well at this stage. However, the next shot shows the anchor digging in well while moving back very little.

Anchors are very consistent but these sort of minor variations occur. An anchor like Delta would have been completely different. It would have taken many more metres to set and would still not have been as well set with much less bury of the fluke and more heaping up.

Having used a Rocna for five years and a Mantus for a year and a half, I have seen a lot of sets by both anchors. The Mantus does a smidgen better in my opinion. It sets a fraction quicker and deeper with less heaping up, but the difference is minor compared to vast difference between the Rocna and Delta (once again this is just my opinion).

[noelex 77]

This was a Delta. It was dropped quite close to our Mantus.

Substrates like this are very unpredictable so we should be careful judging anchor performance in this type of bottom. However, I do wonder if the Delta had set as quickly and reliably as the Mantus, would everything have been fine? The sand at the drop point looks OK. Unfortunately, the long setting distance of the Delta means that it subsequently ended up in a rocky patch. In fact, I think the rock next to the fluke is perhaps what ultimately stopped the anchor.

The holding due to rocks like this is very erratic. The anchor can jump past the rock, or push it aside with a slight change in direction or increase in force.

Sets like this are very hard to pick from the boat. When the anchor hits a rock it can produce an abrupt tightening of the chain, leading the skipper to believe it is a very firm, positive and reliable set.

Did I mention an anchor alarm is always a good back up .

Edit: As Hoppy suggests, viewing a trace of the boat's movements is even better. I have a GPS next to our bed just for this purpose. Kinky .

[Lure_]

Originally Posted by noelex 77

Hi Lure
Thanks for the kind words. Reading through the entire thread is quite a feat . I think your plan to get the best bow anchor is a good one.

I can understand your request. I am reluctant to not set the anchor though, as I consider this poor practice, but I was forced to do this in post #524 when I managed to get our trolling line around the prop, disabling the engine. This was set in 15 knots of wind, but the sand was quite soft. Nevertheless, you can see a nearby Delta doing much less well in post #543.

The Mantus set with no engine:

I thought that this might happen - that in all the photos, you already had an example where Mantus was just dropped. Seems that I did not notice it when I was reading through the thread.
Thank you very much for finding this photo for me!