Photos of Anchors Setting

[bazzer]

Mhhh, there is something that's just not right with the Bugel. Are you sure the skipper on the boat is setting it right? Does it have a swivel ( to avoid chain twist which could force it to be on its side? )

[noelex 77]

Originally Posted by bazzer

Mhhh, there is something that's just not right with the Bugel. Are you sure the skipper on the boat is setting it right? Does it have a swivel ( to avoid chain twist which could force it to be on its side? )

Yes it has the powerball swivel. I did see the two sets on the hard sand, but I missed his movement onto the quay so I don't know what sort of set he did.

Just went for dive. The Bugel has changed. (Nothing like a bit of mystery and intrigue in an anchor thread )
The internet is very slow at the moment and I cannot get any photos in, but I will update when I can.

[bazzer]

This is the best anchor thread ever, nothing like photos of anchors being used in true life situations.

Ok, in the case of this Bugel I just fail to see how the driver of this boat set the anchor. ie set whilst going aft until the boat came to a full stop. When this happens the rode goes taught and pulls the shank off the bottom at a angle, this would put the fluke flat on the bottom with point down and at which point the anchor would dig into the sand until the boat stops or the anchor, if it's to small, should plough along the bottom. This clearly did not happen with this boat, the Bugel has a very sharp point, and the anchor was dragged gently along the bottom on it's resting side.
Don't you think?

[noelex 77]

We have had little wind (perhaps 15 knots), but when Med-moored there is a bit more pressure on the anchor with any crosswind. This together with soft substrate and relatively small fluke area of the Bugel has been enough to set the anchor better.

The fluke is now further dug in and the list is down to 20 degrees. Reassuringly it has done this better set with minimal movement backwards. Anyway it is now a good set. It is well buried. I would prefer to see less list, but this is decreasing as it buries. (The Bugel is a bit more prone to mantaining a list at a stage in the set when newer roll bar anchor anchors would have levelled out)

Notice how rapidly the drag marks are filling in. They are barely visible. This will only happen in softer substrate.

[DoubleWhisky]

The photos of the Bugel are particulary interesting. With it quite sharp tip I would expect better set from it. With a list, even of the 20 degrees only, it will be not good enough in the crosswind when used for Med mooring, I suppose...

[noelex 77]

A moderate list on the anchor would not concern me too much when Med-mooring where the direction of pull is constant.
It is also not of much concern with a wind shift if the change in direction of pull is tending to level the anchor.
The worry comes when there is a change in direction of pull that will increase the list.

So rotation in one direction will be OK in the other direction the anchor may break out with a relatively small wind shift.

Ideally an anchor will rotate to level very quickly and stay as level as possible with a change in the direction of pull. Some anchors do these things better than others and this is not usually revealed in the straight line holding tests that are conducted.

One factor to consider is that if you set with increasing amounts of reverse (as I do) in light wind the boat will tend to gradually change the direction pull in response to the prop walk. This means that most times you tend to have a list in the same direction. It does depend which side the anchor falls over when it is adopting the setting position. There are only two options falling: to the right or left. If you can get the anchor to fall the right way so the prop walk will assist in levelling the anchor the set will be better.

This is not a factor with moderate or strong wind, as this will counteract the prop walk.

What you don't want, is the anchor to fall over in a direction that induces a list in the same direction as the prop walk and a future wind shift. These effects can all induce a list in the same direction, especially if you have an anchor that does not rotate and stay level well.

This is advanced anchoring. The basics are much more important. Non of the above is even mentioned by the anchoring textbooks. Only anchorholicis need to consider these factors

[Sailor g]

Originally Posted by noelex 77

...only anchorholicis need to consider these factors

Yeah, but an anchorholic will still be there when the wind hits the fan! I'd rather be behind/next to an anchorholic than the other kind!

[noelex 77]

This boat is also Med-moored. The anchor is a Bugel copy. 6m @ 6:1. The genuine Bugel and this Bugel copy are anchored are only 15m apart, but the skipper has managed to drop his anchor on a patch of weed. These patches can be seen from the surface so most people would avoid dropping here so it's also likely to be a substrate that has not seen many anchors and therefore will be harder.

The weed is only light and should not trouble the anchor. It has set reasonably rapidly, but with quite a list (40 deg). At this stage it is a bit more of scrape than a convincing dig in, but once again a bit more force is needed to decide if the anchor buries convincingly.

[bazzer]

This anchor along with the other Bugel has just not been set properly. There is no way that these anchors would have stopped the boat going aft if any revs had been applied.
Not a good ad for Bugel at all.

[bazzer]

Originally Posted by noelex 77

This boat is also Med-moored. The anchor is a Bugel copy. 6m @ 6:1. The genuine Bugel and this Bugel copy are anchored are only 15m apart, but the skipper has managed to drop his anchor on a patch of weed. These patches can be seen from the surface so most people would avoid dropping here so it's also likely to be a substrate that has not seen many anchors and therefore will be harder.



The weed is only light and should not trouble the anchor. It has set reasonably rapidly, but with quite a list (40 deg). At this stage it is a bit more of scrape than a convincing dig in, but once again a bit more force is needed to decide if the anchor buries convincingly.

Also, what is that metal attached to the shank?

[noelex 77]

Originally Posted by bazzer

Also, what is that metal attached to the shank?

Well spotted.
I presume it has been attached to the anchor to retain the anchor on the bow roller. You cannot see very well from the photo but there is one each side of the shank. They were thin U shaped bits of metal.

I think the function was to stop the shank flopping from side to side on the bow roller. Any other theories?

[noelex 77]

There has been a bit more wind again. Still not much at 20 knots, but it had a fair downwind/crosswind component so there was a bit of strain on the anchors of the Med-moored boats.

As you can see the Bugel has set further. It is now perfectly level. If it was not for the roll bar there would be nothing to see and it won't take much more wind for this to disappear. Unfortunately the soft sand has filled in the evidence of the drag marks, but looking carefully at the photos I think it has moved back very little when digging in deeper.

This is a great result, but for this to occur at such a low force does show, more than anything, how soft the sand is in this particular spot. The sand here is normally hard, but this spot has been ploughed up by all the boat anchors. This sort of medium soft sand is the natural substrate in many parts of the world. In those locations similar sets (or deeper with a bit more wind force) are the norm.

In medium-soft sand it is very hard to judge much about anchor performance. All anchors do well and set deeply. They also hold well.

It is in hard, weedy, or alternatively the other end of the scale in very soft substrates that the differences between the good and not so good anchors become apparent. There are also differences in distance taken to set, and in resetting ability, but even these differences are minimised when you test in close to an ideal substrate.

[NornaBiron]

We have had an interesting and slightly disturbing incident with our 45kg Spade. A few days ago we had a good set using full power. We then had a 180' wind shift, the wind was only blowing around 20 knots. I was out diving as another boat had anchored in front of us and I noticed that our Spade had flipped on its back. My better half started up and reset the anchor whilst I watched (unfortunately I hadn't sussed the video function of the camera at that point!). The anchor rolled up the right way and set within 1m.

I was very surprised that it had flipped and not rotated

[noelex 77]

Thanks NornaBiron. You have something that very few have seen in real life. Thanks for sharing the photos.

There are many that believe this flip and breakout method of resetting is common. Your photos show a Spade will do this in even mild wind conditions. I am surprised, but I think that is what this thread is about to learn what is happening underwater. Although the thought of the anchor breaking out in this manner is the sort of thing to give a cursing sailor nightmares.

I have never seen my Rocna (or Mantus, but I have only he'd this for a short time) do this. The marks in the sand persist for a long time in the hard sand of this area so you don't have to see it occurring in real time (although it makes great photos )as NB has documented. The flip would be obvious on a dive the next day or even the next week.

I wonder if the roll bar anchors are more resistant to this sort of behaviour than other anchors? They do rotate in a very level fashion and perhaps the roll bar itself provides some protection. With a non roll bar anchor a 180 degree shift leaves the chain coming backwards along the fluke. The force has almost no rotational component. The roll bar (if exposed) ensures the chain is deflected sideways ensuring a rotational force on he fluke. This advantage will be lost in soft substrates where the roll bar is completely buried, but the deep penetration would make a flip less likely.

[noelex 77]

There don't seem to be many photos of anchors performing in the real world and even fewer of an anchor gradually burying deeper in response to natural wind pressure, so here are the three photos of the Bugel at the various stages over a couple of days.