Photos of Anchors Setting

[Sun and Moon]

Thanks Steve for the video and the excellent commentary!

In some ways this confirms my experience with my Manson 15, which is similar to the Rocna. Mud is it's least favorite bottom. The only time I ever dragged was a very soft mud bottom and 180 degree current reversal. My subjective belief is that my Fortress holds better in mud, but I haven't tried reversing on it.

After watching the video, I have lots of questions...

How well was the Rocna in your video set? It didn't look like it was buried the way Noelex burries his Mantus, with only the roll bar (or less) exposed. With a better bury, might it have shuffled effectively?

Do you know what the bottom is actually composed of? Could there be a hard layer just below the soft layer of mud that the relatively light Rocna could not penetrate?

Would greater scope help the Rocna reset under these conditions?

Would painting the flukes with a high-gloss paint discourage the mud from sticking and fouling the anchor?

Again, thanks for the best thread on the internet!

[eheffa]

Originally Posted by noelex 77

The rotation of anchors to a new wind direction is a very important property. All anchors lose some grip while they are rotating and if an anchor is going to drag it is a common time for this to occur.

I believe anchors that rotate well should always, or at least very nearly always, "shuffle" as they rotate around to new wind direction, providing the two criterion of a reasonable set and reasonable substrate have been met. An anchor that "shuffles" rotates, but does otherwise not move. It remains with its flukes buried and retains its grip on the seabed.

The alternative is that the anchor breaks out, drags, and hopefully resets. This is very unreliable. No matter what design of anchor we have, if it then encounters debris or unsuitable substrate, it is not going to set.

So I think the focus should be on anchors that shuffle well. This is quite easy to judge underwater. Anchors that perform well remain with their flukes well buried throughout the rotation with little list. Anchors that rotate poorly develop a high list and lose grip over most of the fluke area. Anchors that rotate poorly still will not break out on most rotations, but they lose so much grip while rotating it is obvious that they are vulnerable to a gust at the wrong time. I think even small differences in an anchor's ability to shuffle in a competent fashion is an important distinction between different anchor models.

Steve's videos are interesting, but my experience with our Rocna and observing others is that "shuffles" very well and I think this is the key to an anchor that is going to rotate reliably.

Thank you for this reasoned reply.

It makes sense that this mechanism of a back-flip wrenching of the embedded anchor would be a rare scenario & not representative of the anchor's normal response to a shift in current or wind direction. It is concerning that the Rocna & Manson supreme do not recover so well from this treatment as do the Spade or Mantus or the Sarca models; at least in a mud substrate.

Perhaps a more appropriately sized Rocna for further testing would help to answer the concern that this behavior was at least partially due to an undersized sample being stressed beyond its rating?

[Panope]

Your welcome, Sun and Moon. I'll answer your questions below, in red.

Originally Posted by Sun and Moon

Thanks Steve for the video and the excellent commentary!

In some ways this confirms my experience with my Manson 15, which is similar to the Rocna. Mud is it's least favorite bottom. The only time I ever dragged was a very soft mud bottom and 180 degree current reversal. My subjective belief is that my Fortress holds better in mud, but I haven't tried reversing on it.

After watching the video, I have lots of questions...

How well was the Rocna in your video set? I use have used the same setting procedure for all 16 anchors that I have tested: Boat backing at 2 knots (boat weighs 15K lbs.), followed by generous reverse engine power (40 hp Yanmar with a BIG fixed 3 blade prop). It didn't look like it was buried the way Noelex burries his Mantus, with only the roll bar (or less) exposed. With a better bury, might it have shuffled effectively? Possibly. However, short of hiring a towboat to set my anchor, there is little else I can do.

Do you know what the bottom is actually composed of? I call it "sandy mud" Could there be a hard layer just below the soft layer of mud that the relatively light Rocna could not penetrate? Definitely not. This substrait is very very consistent and is ideal in that it is easily penetrable and provides excellent holding power.

Would greater scope help the Rocna reset under these conditions? I believe that greater scope would lessen the chance that the anchor would break-out in the first place. However, once the anchor has broken free (and has some seabed attached) I feel that greater scope would be of little help because even at the very short scope of 2.5 to 1, the dragging anchor does not provide enough resistance to remove the chain catenary.

Would painting the flukes with a high-gloss paint discourage the mud from sticking and fouling the anchor? Perhaps. Note: The paint that was applied to my SPADE anchor fluke (by the factory) has already fallen off. Painting galvanized steel is problematic.

Again, thanks for the best thread on the internet!

Steve

[Palarran]

We have had a solid week of the Meltemi blowing here in Greece. Starting up in Skiathos we anchored in 80' of water on an unknown bottom with 340' of chain out in 35 knot winds and held firm through the night. Since then we have had pretty constant 30 knot winds and not had any problems with mostly sandy or mud bottoms. Today we are in Botsi on Andros in 25' over sand. The water was clear so I did take a picture. We applied zero back down on the anchor as the wind was doing an excellent job itself. Pretty solid set and very quick. I also included a picture of our new chain hook. I like it but it's difficult to engage on the chain.

[skipgundlach]

We have one of those chain hooks. However, we engage it topsides, as the chain's going out, and the single 1" megabraid snubber just goes down with it.

We have had perhaps one instance of it separating from the hook, and that was in total calm, with too much out (it was on the bottom in shallow water); we also find it disengages easily once it's topsides.

Your paired snubbers would make attachment a bit more of a challenge, but it's ideal in a cat.

By 'engage' do you mean 'get it onto' or 'get it to stay'? Once I have mine engaged, I just drop my chain loose, with the tension being me on the snubber, until I get it to the cleat length I want. I've had occasional disengagement as it went over the roller, but even those are very rare. I like it a great deal, and recently changed snubbers just so I wouldn't have to worry about wearing through and losing this wonderful piece of stainless. I wish I'd thought about a thimble, though I've never spliced Megabraid to a thimble, so I'm not sure how tight it would be...

If your complaint's not a size issue, try playing with deployment tension after your hook is on the chain...

[noelex 77]

Another fixed convex plow anchor doing a good job in this next to ideal substrate. This is a Kobra in 8m @ 4:1.

There is some heaping up of the substrate, but this is a much better result than seen with this class of anchor in harder sand.

[noelex 77]

A new anchorage. The cruising guide reports the bottom as "sand". Sadly this is not the whole truth. There are large patches of rock scattered through the anchorage together with lots of fist sized rocks that can be enough to upset the set of an anchor, especially if they are encountered below the surface. However, there are some reasonable sand patches. I suspect there is rock under these, but the sand patches are deep enough in a lot of places to get an adequate grip.

It is in situations like this where an oversized anchor is particularly advantageous. A large anchor cannot penetrate rock any better than small one, but it has enough blade area to get an acceptable hold on the sand above the rock.

You can see the patches of rock just a few metres from the Mantus. It is one of this anchor's poorer sets. Although the list is significant, 3/4 of the fluke is still buried and I felt this was adequate for the 30 knot forecast, although I did increase the scope to 7:1 in 8m, more than my customary amount for this wind strength.

This type of anchorage is where a reliable interpretation of a fishfinder/sonar result would be helpful. The rock patches were impossible to distinguish from the sand when anchoring, despite the clear water.

[Palarran]

Originally Posted by skipgundlach

By 'engage' do you mean 'get it onto' or 'get it to stay'?

Get it onto. The whole bundle is difficult to get to line up so that the hook goes on to the link easily. What I'd like to do is have someone braid the line directly onto the hook without the shackle.

[noelex 77]

This is a Delta. It was dropped close to our Mantus. 8m @ 5:1. The substrate is similar with the same solid rock in patches around the anchor. You can see some of this in the background.

Once again, I suspect that there is rock under the sand, but the Delta often has trouble penetrating deeply even in just hard sand. The set is only a little worse than is typical for this anchor.

[noelex 77]

I don't normally photograph debris on the bottom, particularly man made rubbish, but there are a couple of take home messages seeing this.

• Even a small item like these swim trunks could be enough to prevent an anchor from setting properly if it wraps around the fluke. An anchor that sets rapidly is good defence, as is testing the set with a reasonable amount of reverse. But this is not foolproof. It is possible that even a rapidly setting anchor could be unlucky enough to get entangled with something like this and the anchor could hold a reasonable amount of reverse force, but still not be performing normally. Use an anchor alarm as a back up.
  
• Some of the debris has not been thrown away, but items like this that have been blown off boats. These swim trunks still have the peg attached in a rather painful spot . Please secure items particularly well if you leave them on the lifelines to dry. Even on a calm day a gust is often enough to blow away items secured only with one or two pegs. It can be particularly harmful in coral areas where this will cut off light and kill the coral. Besides, someone has lost their shorts, and we don't need any more men without shorts in the Med .

[Jim Cate]

Nolex, we actually speared a pair of board shorts on the "arrow" nose of our Manson Supreme! As you suspected, it failed the reverse pull test immediately. We recovered the shorts, but sadly they were not my size and had a big, anchor-shaped hole in them!

Jim

[kas_1611]

Hmmm a patent opportunity presents - floating marine pegs, hold items securely but stops them sinking just in case

Even if they only stopped things sinking for a minute it would give you a chance to grab hold of them. It is amazing how quickly a towel sinks below the surface.

It is sad that people do not make any attempt to recover items but I suppose that is in indication of how society is these days.

[Snowpetrel]

I remember someone describing a glass bottom. I thought theu meant it was slippery bottom, but it turned out they meant years of yachties throwing glass bottles overboard had made for treacherous holding, as you were likely to pick up the broken remains of a bottle.

[skipgundlach]

Originally Posted by Palarran

Get it onto. The whole bundle is difficult to get to line up so that the hook goes on to the link easily. What I'd like to do is have someone braid the line directly onto the hook without the shackle.

Ah. That's exactly what we did; splice the Megabraid onto the hook. I can see how the shackle would make things a bit challenging.

Are your bridle lines pre-made - that is, you bought them that way, rather than did the splice yourself? That might explain the thimbles which engage the shackle. Thimbles, even if done ON the hook, might represent the same opportunity for engagement challenge.

I'd bet, if you had some three strand - or, even, just reverse the ones you have; the worst you'd suffer is having to cut it off and lose a few inches on each, if you decided you wanted to go back to what you had - that someone in an anchorage you share would be happy to splice two lines to your hook for a beer or even just conversation. It's a piece of cake, won't take an hour even if all you had was a screwdriver and a knife, and if you were here, I'd do it.

I believe your engagement issues would go away if you had a tight splice for those lines, directly to the hook...

[NornaBiron]

Originally Posted by noelex 77

I don't normally photograph debris on the bottom, particularly man made rubbish, but there are a couple of take home messages seeing this.

• Even a small item like these swim trunks could be enough to prevent an anchor from setting properly if it wraps around the fluke. An anchor that sets rapidly is good defence, as is testing the set with a reasonable amount of reverse. But this is not foolproof. It is possible that even a rapidly setting anchor could be unlucky enough to get entangled with something like this and the anchor could hold a reasonable amount of reverse force, but still not be performing normally. Use an anchor alarm as a back up.
  
• Some of the debris has not been thrown away, but items like this that have been blown off boats. These swim trunks still have the peg attached in a rather painful spot . Please secure items particularly well if you leave them on the lifelines to dry. Even on a calm day a gust is often enough to blow away items secured only with one or two pegs. It can be particularly harmful in coral areas where this will cut off light and kill the coral. Besides, someone has lost their shorts, and we don't need any more men without shorts in the Med .

I hope you checked the pockets, a friend of ours found a (still working) genuine Rolex watch in a pair of shorts he found on the bottom in Meganissi.