Photos of Anchors Setting

[cwyckham]

Originally Posted by nigel1

I have been anchoring out frequently on the West Coast of Scotland, mainly in the Firth of Clyde area, and getting the scope right can be a challenge. A lot of the anchorages shoal steeply. If you put out sufficient scope to allow for the deep water, it will usually mean that if the boat drifts towards the shore, it will ground.

In these situations I tend to keep the scope short and rely on the anchor makers claims to high holding power , and the anchor alarm.

If it drops of steeply enough, the only real option is to stern tie to shore so that the pull on the rode is "uphill". Otherwise, if you swing around so you're being pulled towards deeper water, you'll be at a very low effective scope due to the slope. If you've already been forced to reduce scope to stay off the shoreline, then you may be at a 1:1 effective slope with an offshore wind.

Of course, once you stern tie, then you have the issue of high forces from a beam-on wind. The stern tie needs to have as much slack in it as possible to minimize the effect. At least you'll be pulling your anchor uphill, though. The very large effective scope and gravity will both be in your favour.

Stern tying is very common in the PNW due to tight, deep anchorages. It also means you can pack a lot of boats into a tiny anchorage because nobody's swinging.

[monte]

Another good instant set by the kobra. 5:1 in 3m Tyrell bay.

[noelex 77]

The wind has been regularly switching around 180° every day. This is due to a local seabreeze effect caused by the land heating up more than the water.

Many people imagine that when a change in wind direction occurs, the anchor is rotating around, but it takes a moderate wind force to do this. All anchors up to now in the anchorage have stayed put, but there was a little more wind this time (in the low 20's). There was also some wave action caused by the onshore wind that was pitching the cats up and down contributing to force on the anchor. It was just enough force to cause the two Rocnas to rotate.

This is the start of the rotation for the first Rocna (see post #1439). Unfortunately, the rotation direction is such that it is going to exacerbate the list that this Rocna already had after setting.

This was the starting point (from post 1439):




These two photos show the start of the rotation:

[noelex 77]

Unfortunately, I missed seeing this rotation, but the marks in the sand tell the story.

You can see it has not done well. The anchor has moved back about four feet or so.

It looks like during the rotation it developed a high list with poor grip. I suspect from the marks it did not break out completely, but it came close. This is nothing like the correct sort of shuffle around that the anchor should be doing.

This is a very atypical result from the Rocna. I had a Rocna on my bow for 5 years so I have seen it rotate on many occasions. I have never seen it do anything other than pivot about a fixed point. As I have noted, the substrate in this spot is unusual with anchor performance noticeably worse than normal.

Anyway, the purpose of this thread is to show real world performance of all the anchors we see. The good and bad, typical and atypical will all be shown.

[hoppy]

What do you expect the Rocna to do when the direction changes? I would have thought it looks good, ready to dig in if the wind picks up?

[JPA Cate]

Hoppy, noelex started writing about the Rocna and other modern anchors "shuffling" around in strong enough wind changes long before he showed pictures of it. You gotta wait on the photo ops!

There are some pics of it way back in the thread. I don't know if it will work, but try searching the thread using the "anchor shuffling" for what it is supposed to look for, and maybe that'll get you there. Or try a Google Special search, using the same. One or the other will probably do the trick for you.

Good luck with it.

[noelex 77]

Originally Posted by hoppy

........ready to dig in if the wind picks up?

I agree. The Rocna still has some of the fluke buried and with some more force in the new direction the anchor is very likely to dig in and rotate level.

This sort of small movement (about four feet) is too small to detect reliably with transits or GPS. It would not be noticed by the skipper unless he took a look underwater.

An anchor that rotates like this will generally re-set, but this is not always the case. If the anchor loses most of its grip during the rotation in strong wind and starts to move backwards, there is a risk it will continue to do so. A moving anchor has a lot of trouble starting to bury.

Even in light wind, movement like this can cause the anchor fluke to become clogged with weed or debris. This is especially true of the anchors that take a long distance to set. There is also a risk the anchor will move into an area of unsuitable substrate.

So while in most cases the anchor will reset, this sort of movement with rotation is not 100% reliable. An anchor that "shuffles" maintaining its fluke buried with a high amount of grip, and pivots about one point without moving is much better.

Here are some examples of an anchor "shuffling" around. This is my Mantus. You can see the scrape marks as the shank has rotated around without the anchor otherwise moving:



This is sequence, in a different anchorage, showing the Mantus "shuffling":










And another sequence:








Note these examples are in a different substrate.


The Rocna is an excellent anchor. I am a big fan of this design. It normally rotates very well. This is an atypical result in an atypical substrate.

The strength of these photos is that they are not selected images, but rather show every single anchor myself, or my mermaid have managed to see since we got the underwater camera 15 months ago. I feel it is important to maintain this approach even when the images show an uncharacteristic performance. I think it is still very clear from the multitude of examples which are good and not so good anchors, despite occasional outlying results like this one from the Rocna.

[noelex 77]

his was the other Rocna, from post #1466.

It is an anchor one size smaller (33kg) dropped by the same sized cat (Lagoon 420). This was taken at the same time as the photo in post #1473

To remind you this is how it looked after the original set:




This is in the very early stages of rotation. It has barely changed other than tipping just slightly:



How will it rotate? This was taken at the same time as the other Rocna rotated and they were within a few boat lengths of each other, so I know, but you will have to wait until I can sort out the images .

[noelex 77]

Here the above Rocna has now rotated 180°. From the marks in the sand you can see that this anchor has also not quite "shuffled" properly. In this case it has only moved about a foot, but this is still not a great performance. The anchor has moved, not just rotated and has been left with a significant list. With more force I would expect it to bury more and rotate level but at this stage it has less grip. It is likely during the rotation itself the list was probably a bit worse.

Once again I think this relatively poor performance is just indicative of the substrate at this location. It is very unusual performance for a Rocna.

These two Rocnas were dropped quite close together and it is no surprise they have performed in a similar way, both in the initial set and when rotating around to a new wind direction.

[noelex 77]

After the Rocna excitement, this is a bit boring.

It is a Danforth style anchor that has been dropped in weed, but no force has been put on the anchor with the chain in the weed supplying all the needed grip. This tells us nothing about the anchor performance, but I have included it for the sake of completion.

[noelex 77]

People tend to freak out about boats anchoring close.

My experience is that you are far more likely to be hit by another boat dragging than another boat swinging into you. The other consideration is that a dragging boat will generally hit with a lot more force.

However, collisions with boats swinging into you do occur. The wind here has been light, but this island is affected by a SE sea breeze, which is in the opposite direction to the prevailing NW wind. Particuarly in the transition period when the breeze is changing, boats can end up lying quite differently.

Last evening a small (32 foot?) beautifully maintained ketch anchored between us and a large cat. There was not a lot of room in this gap. Unfortunately, I missed seeing where they where they dropped their anchor. Those manual anchor winches can be so damn quiet. Sneaky

Where the anchor is dropped in relation to your anchor is really the most vital information when deciding if there is a risk of collision. I did ping them with the laser rangefinder when they finished anchoring and they were 24m from our side and 20m from the large Cat.

These sort of distances are normally safe, but a small ketch, a large monohull (us) and a large cat, all reasonably close with light variable wind is not a good recipe. The patches of weed and rock in this anchorage also do not help. The chain can get caught in these substrates, especially in light wind keeping the boat relatively stationary while a neighbouring boat with chain that is not caught moves as the wind changes. Fortunately, we all had a similar scope although at around 40m this left reasonably large swinging circles.

Anyway around 2am (the bewitching hour for anchoring) the cat and the ketch looked close. With a quick look through the binoculars they were swinging at times what looked only a few metres apart (good binoculars really enhance night vision). I have also found the laser rangfinder great for this. You can measure distances even of objects you cannot see. However, in this case rather than waste time with the rangefinder I felt it was better to wake up the skippers.

The best way is high powered torch (flashlight). If you can shine this through the windows it usually wakes up people at night more effectively than a foghorn and importantly does not disturb others.

The skipper was grateful to be woken. He left his anchor in place and simply motored away from the cat. Unfortunately, towards us . This is not generally effective. Boats don't stay where they are "parked" and re-anchoring further away would have been much better. Nevertheless, there was no collisions.

This was a photo I took at night. They look in the photo more than a few metres apart so perhaps my estimation was a bit pessimistic, or perhaps they had just swung a bit further apart at this stage. Anyway, presented with this situation I would want to woken up by another boat to make my own assessment.



This was the next morning. The perspective of the photo makes is appear a bit closer than we were in reality. It was about 10m at this stage, and the gap widened as the wind picked up.

[kas_1611]

Originally Posted by noelex 77

After the Rocna excitement, this is a bit boring.

It is a Danforth style anchor that has been dropped in weed, but no force has been put on the anchor with the chain in the weed supplying all the needed grip. This tells us nothing about the anchor performance, but I have included it for the sake of completion.

It's good to show the Bad and the Ugly alongside the Good so we know what they look like. I've seen several Danforth/Brittany style anchors just lying on the seabed with no sign of setting just waiting for the wind to pick up so they can slide along the sand

[hoppy]

Originally Posted by noelex 77

People tend to freak out about boats anchoring close.

My experience is that you are far more likely to be hit by another boat dragging than another boat swinging into you. The other consideration is that a dragging boat will generally hit with a lot more force.

However, collisions with boats swinging into you do occur. The wind here has been light, but this island is affected by a SE sea breeze, which is in the opposite direction to the prevailing NW wind. Particuarly in the transition period when the breeze is changing, boats can end up lying quite differently.

Last evening a small (32 foot?) beautifully maintained ketch anchored between us and a large cat. There was not a lot of room in this gap. Unfortunately, I missed seeing where they where they dropped their anchor. Those manual anchor winches can be so damn quiet. Sneaky

Where the anchor is dropped in relation to your anchor is really the most vital information when deciding if there is a risk of collision. I did ping them with the laser rangefinder when they finished anchoring and they were 24m from our side and 20m from the large Cat.

These sort of distances are normally safe, but a small ketch, a large monohull (us) and a large cat, all reasonably close with light variable wind is not a good recipe. The patches of weed and rock in this anchorage also do not help. The chain can get caught in these substrates, especially in light wind keeping the boat relatively stationary while a neighbouring boat with chain that is not caught moves as the wind changes. Fortunately, we all had a similar scope although at around 40m this left reasonably large swinging circles.

Anyway around 2am (the bewitching hour for anchoring) the cat and the ketch looked close. With a quick look through the binoculars they were swinging at times what looked only a few metres apart (good binoculars really enhance night vision). I have also found the laser rangfinder great for this. You can measure distances even of objects you cannot see. However, in this case rather than waste time with the rangefinder I felt it was better to wake up the skippers.

The best way is high powered torch (flashlight). If you can shine this through the windows it usually wakes up people at night more effectively than a foghorn and importantly does not disturb others.

The skipper was grateful to be woken. He left his anchor in place and simply motored away from the cat. Unfortunately, towards us . This is not generally effective. Boats don't stay where they are "parked" and re-anchoring further away would have been much better. Nevertheless, there was no collisions.

This was a photo I took at night. They look in the photo more than a few metres apart so perhaps my estimation was a bit pessimistic, or perhaps they had just swung a bit further apart at this stage. Anyway, presented with this situation I would want to woken up by another boat to make my own assessment.



This was the next morning. The perspective of the photo makes is appear a bit closer than we were in reality. It was about 10m at this stage, and the gap widened as the wind picked up.

In Lakka on Paxos it can get very cosy, especially when the flotillas are there.

This is empty for Lakka

[hoppy]

I might actually be contributing photos to this thread soon. Mast is back on, new bowsprit installed and Vulcan is ready...

Will probably go to Lakka for my first photoshoot

[rgesner]

Noelex,

What brand/model of laser rangefinder do you find "great for this?"

Thanks - Rusty