Photos of Anchors Setting

[JPA Cate]

Noelex,

Is the Delta's shank bent slightly? It looked sort of like it in the picture. And if so, what's your take on how that affects its setting and holding ability?

Thanks.

Ann

[noelex 77]

Thanks for the comments.

The bend is just an illusion. The anchor is a bit more tipped than the photo suggests. The camera lens might also have a little distortion in it as most are taken at maximum wide angle.

More photos to come. You won't believe what happened next....

[NornaBiron]

Originally Posted by noelex 77

More photos to come. You won't believe what happened next....

waiting with baited breath!

[Sos]

The tension is too much

As said elsewhere, these pictures are so good, and this has got to be the best anchoring thread and there has been a lot of those!

[noelex 77]

My Mermaid went for her pre-breakfast swim and took these great photos of what happened to the Delta overnight. The wind switched around almost 180 degrees, but was only light (perhaps 15 knots ?).

The genuine Delta performed very poorly after its 5m drag yesterday. Overnight it dragged another 2m in the opposite direction and now looks set worse than when it began.

Of course the skipper was unaware of this. The anchor had dragged back to within a few metres of where it was dropped. It is not unusual to see this situation where an anchor is performing poorly, but the skipper has no idea.

The Delta is not normally this bad, but this result deserves some serious criticism of how the anchor performed given that it was close to perfect substrate with two very experienced people on board. If you are considering buying a better anchor I hope even this single result will convince you of the difference between a good and an excellent anchor.

I often see boats sleeping overnight while trusting anchors that are doing this sort of thing. I hope you can forgive some passion and enthusiasm when I try to steer people away from anchors that behave like this.

[kas_1611]

I am really surprised how badly the Delta did in this anchorage. Normally in good sands they set very well and hold brilliantly, well in my experience anyway. Sometimes yes they can take a few meters to really dig in but then they are a "plough" type anchor and as the name suggests they need to plough in. One thing to take for this though is the anchor did reset quickly after a 180º swing.

Could this performance be substrate related in that the sand is actually too soft for the Delta? Perhaps it is related to the shear strength of the sand.

I have swam over my own Delta in a sand bed, seen it set in a similar manner (maybe a tiny bit deeper) after a few meter furrow, then watched other boats slowly disappear backwards in 25kt winds while we held without problem.

It must also be taken into account that there is not 1 universal anchor that will work perfectly in all conditions and all substrates but it has been an eye opener to see these photos it has to be said. Many thanks to the Mermaid for taking them.

Keiron

[noelex 77]

Not a very good photo but this patch of weed is waiting only 7-8 m from the Delta.

Will it dig in and hold before reaching this? It has dragged 7m so far.

The Delta is struggling in the med- soft sand. It does not have much hope in this medium weed. Then it has only got a few meters of sand before almost continuous medium weed, like this, with an increasing depth and decreasing scope.

Do you feel lucky punk

Notice how the chain provides some grip in weed. Weed like this can give the illusion that the anchor is holding, but as the wind increases the catenary disappears and the chain lifts off the bottom. The grip of the chain in the weed is lost, and the anchors holding becomes the only factor restraining the boat.

Testing the anchor at full reverse will eliminate most of this catenary and simulate the response to medium strength winds, showing if the anchor itself is holding.

[ImaginaryNumber]

Originally Posted by kas_1611

If you want a good technique for checking the set in colder waters then can I suggest something that I saw from a local fisherman. He was checking his fishing pots with a 1m square box with a perspex bottom. He threw it in from the side of his boat and as it floated over the area he was able to see his pots clearly. Simple and removes the terror of sticking your face in cold water with a snorkel mask which is what I have done in the past

Cheers

Keiron

Keiron, thanks for the suggestion. Is there a reason why it is so large? Would it work effectively if it were substantially smaller, say 300mm square? Maybe it was large just so it would float well unattended, and not get swamped by waves. How deep was it?

[DoubleWhisky]

Originally Posted by ImaginaryNumber

Keiron, thanks for the suggestion. Is there a reason why it is so large? Would it work effectively if it were substantially smaller, say 300mm square? Maybe it was large just so it would float well unattended, and not get swamped by waves. How deep was it?

Here You have a production batyscope:

Demountable bathyscope

Quite useful piece of equipement for anchorholics

[downunder]

underwater viewing bucket

Marine Sports Underwater Viewer Bucket

a better viewer

Bathiscope - Underwater Viewer | Cassell Marine

[downunder]

Originally Posted by DoubleWhisky

Here You have a production batyscope:

Demountable bathyscope

Quite useful piece of equipement for anchorholics

Think you win that DW. Suitable for nightime anchor viewing. I can think of better pursuits.

Then again you are an anchorholic.

[noelex 77]

A bathyscope (spelling?) is great addition if you have moderate visibility.
I use one over the side of the dingy in the colder months to inspect what anchors are doing.

I have a plastic one.

I used to lust after the octopus fishermen bathyscope which is a stainless steel beer keg with the bottom cut out and laminated glass added.
It makes the plastic bathyscope look like a toy

Interestingly, I have found the underwater camera held under the dingy gives better results. The camera will take 5 fps which means you get a good shot of the anchor which can be analysed at leisure and compared to previous results which makes small movements of the anchor easy to observe. I used to drop stones near the anchor to act as reference points, but the photographs usually mean natural reference points can be checked.

If you have a problem say at the prop, or rudder, you can attach the camera to a boat hook and take photos from angles that could not be obtained with bathyscope. Given the cheap cost of waterproof sports cameras it is an option to consider.

Besides, you could post photos of anchors on CF with a camera.

[downunder]

Originally Posted by noelex 77

A batyscope (spelling?) is great addition if you have moderate visibility.
I use one over the side of the dingy in the colder months to inspect what anchors are doing.

I have a plastic one.

I used to lust after the octopus fishermen bathyscope which is a stainless steel beer keg with the bottom cut out and laminated glass added.
It makes the plastic bathyscope look like a toy

Interestingly, I have found the underwater camera held under the dingy gives better results. The camera will take 5 fps which means you get a good shot of the anchor which can be analysed at leisure and compared to previous results which makes small movements of the anchor easy to observe. I used to drop stones near the anchor to act as reference points, but the photographs usually mean natural reference points can be checked.

If you have a problem say at the prop, or rudder, you can attach the camera to a boat hook and take photos from angles that could not be obtained with bathyscope. Given the cheap cost of waterproof sports cameras it is an option to consider.

Besides, you could post photos of anchors on CF with a camera.

Just can't beat an all weather mermaid with camera.

[kas_1611]

Originally Posted by ImaginaryNumber

Keiron, thanks for the suggestion. Is there a reason why it is so large? Would it work effectively if it were substantially smaller, say 300mm square? Maybe it was large just so it would float well unattended, and not get swamped by waves. How deep was it?

Only reason I can think for the size was to allow the fisherman to see a large area. He was using quite large "lobster" type pots so I can only presume he wanted to be able to see the full pot and surrounds. Plus I guess it didn't need to be dead centre to be able to see it. No reason you could not make something smaller and if worried about it sinking a foam float on each corner would aid bouyancy. Can't remember how deep the water was but we can only anchor in a max of 12m (4:1) so would have been less than that.

[noelex 77]

The owner and crew of the "Delta" boat are friends of ours. They came over for my Mermaid's famous home made scones and jam breakfast.

You thought mermaids were only good in the water .

Anyway, after breakfast I went over to inspect the anchor. It had moved a further metre back while we were eating, making about 9m in total. To the Delta's credit it rotated vertical and now looked liked it might set properly. The skipper was a bit horrified by the anchor photos. We agreed to try some reverse engine power as a test, before unfortunately they had to leave.

I was in the water observing as they applied the reverse thrust. This was the final result. The Delta did not drag and did set better, but it is more piling up the sand in front of the fluke rather than diving into the substrate.

Behavior like this indicates the anchor is struggling. Why the Delta was struggling so much in an almost ideal substrate I am not sure. The differences between anchor designs are normally minimised the closer you get to a medium-soft substrate. I did test the bottom with my dive knife and it was nice medium soft sand.

The Delta is not a top notch anchor. It does have a tendency to take a long time to set and to pile up the substrate like this, but this was an atypical bad result.

I see a big difference in performance in harder substrates between the different anchor designs, but this result in softer substrate did surprise me.

Photo one shows the Delta after breakfast. It had moved a further metre backwards and was still very slowly moving. Perhaps a few inches every 15 mins. Disturbing in only 15 perhaps 20 knots of wind almost 24 hours after the anchor was dropped and after traveling 9m. If you look closely you can see the disturbed blurry sand near the bottom of the fluke from this movement. At least it has finally rotated level and looks like it will dig in. The weed bed is in the background.



Photo two shows the result after applying some reverse. The anchor has set better, but it more of pile up of sand rather than a deep diving of the fluke.