Photos of Anchors Setting

[noelex 77]

Originally Posted by Sun and Moon

Do you have any idea why the anchors are having trouble penetrating the bottom? Shallow sand over rock substrate? Loose rock mixed with the sand? Merpeople who don't like your anchors in their floors and ceilings? If the latter, could SWL possibly mediate?

All these are possible, including those naughty Merpeople .

In cases like this, before the camera I investigated the bottom carefully, but now it is a bit too much to try and carry the camera and something to poke into the substrate. At this time of year the water is also quite cold on the bottom so it's not pleasant to spend a long time down deeper. So the bottom line is I am not really sure. All the anchors are doing worse than average.

The most common reasons for problems like this are:

1. A thin layer of sand over sheet rock.
This is usually reasonably obvious because you can see the sheet rock in areas where the sand is washed away.

2. Isolated rocks.
I think this is the most likely main problem here. You can certainly see isolated rocks on the bottom. If these are encounted under the substrate, the burying of the anchor is inhibited. If the wind picks up the anchor can usually push aside small to moderate sized rocks, but there is always a concern that the anchor will encounter a bigger rock. These act a bit of backstop so if the fluke is buried the anchor can still often hold reasonably, but sudden breakouts can occur.

3. A hard sand layer below the soft stuff.
Excellent anchors can usually bury past this but it can take quite a bit of force so the set will be shallower. Most of the modern anchors set first after falling on their side. From here they rotate level as they bury. If they cannot bury they end up with a list.

I think the biggest problem in this anchorage is isolated rocks. This will give quite variable results depending on the luck of the draw so we should be careful about reading in too much about about individual anchor performance.

I think the take home message is that the bottom is very variable. Get yourself the best anchor you can afford and make it as big as you can reasonably manage. Then set an anchor alarm.

There are no absolutes when anchoring.

Here are some of the rocks I have seen:

[noelex 77]

Originally Posted by Aaaskypilot

Going out to practice first time with Ultra 35# on my Gulf32, All chain 5/16. I need ideas on setting it.

Anchoring a boat with poor reverse control is really no different to anchoring a boat that steers well in reverse. You will not generally need a different technique.

When you are applying reverse to set the anchor the boat should (hopefully) not be moving. So there is almost no water flow over the rudder (the prop wash can have a dramatic effect in forward, but very little in reverse) so even a fin keeled boat with a spade rudder has virtually no rudder control when setting the anchor.

Turn the boat into wind. When the boat reaches zero speed, drop the anchor. If there is wind ( even if it light) the boat will gradually drift backwards. Pay out the anchor chain so it matches the boats speed. The idea is to put no force on the anchor at this stage but to lay the chain out downwind in a straight line. When you have reached a scope of about 3:1 you can start applying some gentle pressure to the anchor. This is done just by feeding out the chain at a slower rate.
This will help straighten out the chain and starts the setting process. When you have set out your full scope wait until the boat turns so the stern is facing straight downwind. A full keeled boat will turn in the same way as a fin keeled boat although it will take slightly longer (most sailboats will turn almost beam on as they are drifting back and before any force is put on the anchor). Then gradually apply more reverse. We build up to full reverse and hold that for 30 seconds.

At this stage the boat's stern will stay pointing directly downwind unless there is very little wind and you have a lot of prop walk.

In even very light wind the technique is the same. You will drift back slower so you have to let out the chain more slowly.

In nil wind a boat with good reverse control will be able to control the direction they setting the anchor. It is helpful to set the anchor so that it will be correct for the expected future wind direction, but this is no means essential. A good anchor will rotate with little problem. Likewise, in a crowded anchorage it sometimes helpful to lay your chain out in the same direction as the other boats. With poor reverse control you will find this more difficult to do, but you can usually get the boat moving in approximately the right direction and precision is not needed. You can use the back and fill technique as used when tying to reverse into a slip.

The most vital thing to remember is when you have done all of this, grab your underwater camera and take some photos of the Ultra and post them here. This step is not optional .

[kas_1611]

Don't be afraid to use bow thrusters if you have them fitted to help keep the lay back as straight as you can. In ideal conditions you shouldn't need them but if you have 'em use 'em. A short blast can help keep the bow in the wind as you drop back.

Looking forward to see some pictures of the Ultra to add to the collected knowledge.

Keiron

[malbert73]

Yes- agree with noelex. So many anchor setting disasters happen because people try to drive a boat backwards while laying out their rode. Usually the bow gets caught by wind and boat goes off course to one side. Stopping boat, leaving in neutral and slowly paying out rode as boat drifts is the way to go. I usually let it grip a tiny bit little by little as it goes to ensure chain is straight. Let wind do the work.
I think people learn "back down on their anchor" and don't realize that short of med mooring, this means just use engine to set the anchor, not literally back all the way down.
Only exception is flat calm. Then controlling boat is easy-ish so you can back in setting direction. I still often wait for a zephyr or tide to take boat in set direction. Then set with engine.


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[noelex 77]

This was a stainless steel Brittany anchor. These are quite popular, especially on French yachts. It is a design very much like a Danforth. The stock is shorter, which seems to reduce (although unfortunately not eliminate), the tendency for the Danforth to break out with a change in direction of pull. The flukes of the Brittany are also more tapered than the Danforth which helps it penetrate in harder substrates and in weed. The drawback is the fluke area is smaller so it does not have the same holding power in very soft substrates.

The Brittany seems a partially successful attempt to make the Danforth design more versatile, but many modern anchors do this much better and it has been largely superseded.

It was dropped in one of the slightly weedier patches in the anchorage. It is not doing a very good job. You can see it has a large list, with the flukes almost at 90 degrees.

When I got back to look at the photos I noticed what looked like an old chain over the stock. I did not notice this diving. Usually I can see detail much better than you can see in the photo, but I guess I was concentrating too much on framing the shot.

I should have gone over and told them when I saw the photo, but I was not 100% sure what I was seeing in the photo and I thought I would probably go for another dive before they left and check. By the looks of it the chain was probably doing most of the holding so maybe they were better off with it in place overnight?

I felt a bit guilty because they raised the anchor before I went for another dive and it was tangled. It came to surface easily and it did not take them long to free it, so no harm done .

Problems like this are good reason to get a powerful windlass and sturdy bowsprit. An anchor that sets quickly also reduces the risk of tangling these old mooring chains.

[noelex 77]

Isn't this a great anchor photo? Yep, it's my mermaid's .

If you look in the top left hand side of the photo you can see the dark smudge of the yacht on the surface:



I watched them drop and they tried to set beam on to the wind. This is not a good idea. The yacht is still governed by the wind force and spiralled around. All anchors hate this. They require a pull in a steady direction to set well:




The Delta has been dragged 4-5m to reach this point. It really should have set better in this distance, but this changing direction of force is tough on an anchor and as we have seen, it is an unusual substrate where anchors are not setting well.

[Dockhead]

Originally Posted by kas_1611

Don't be afraid to use bow thrusters if you have them fitted to help keep the lay back as straight as you can. In ideal conditions you shouldn't need them but if you have 'em use 'em. A short blast can help keep the bow in the wind as you drop back.

Looking forward to see some pictures of the Ultra to add to the collected knowledge.

Keiron

So I'm not the only one who does this I use the thruster more anchoring than docking.

Sent from my SGP521 using Cruisers Sailing Forum mobile app

[noelex 77]

This is another convex plow anchor: the Shark.

It was dropped by a private boat that only stayed a few hours. They only let out a small amount of scope in 9m @ 3:1 and gave the anchor only a small setting force. They were planning a short stay, lunchtime anchorage.

The anchor is totally unset, but this does not tell us much about how the anchor performs. Even a great anchor given no force will just sit on the bottom. There was almost no wind.

There is nothing wrong with a more casual approach when stopping for a short time in settled conditions with a begin forecast. However, I think they may have been too casual. They were anchored close to other boats, and left the boat unattended (but still in visual range) for sometime.

It does not take long to do a better job. Anyway, consider that if you take such a casual approach this is what your anchor will look like. At the moment the anchor has very little grip.

[noelex 77]

This was a Rocna dropped by a private boat in 11m @ 5:1.

They did not put much setting force on this anchor. Interestingly they dropped the anchor, paused for about 10 minutes and the applied some reverse.

The Rocna has set very quickly as per normal for this anchor. It is not a great set by Rocna standards, with a reasonable list and a bit a heaping up. The very short setting distance gives some confidence it would improve with a bit more force. As we have seen, anchors in this substrate are not performing as well as they would normally do.

Interestingly, while all anchors are doing worse the hierarchy remains unchanged with the better new generation anchors still doing significantly better than the ever popular Delta which acts as a good reference point.

How an anchor performs in difficult substrate is very important. All anchors will hold well in the ideal bottom. However, I would urge some caution reading too much into individual results at this anchorage.

With this sort of strange substrate the results will be variable depending on exactly where the anchor is dropped. With some common sense when assessing the results, I think the photos can still give us some insight into the anchor performance. We are unlikely to see a traditional anchor test performed in this sort of substrate so the options for objective information are limited. How an anchor performs in a difficult holding ground is one of the most important parameters.

[Kenomac]

I got to see first hand and up close how our Ultra anchor sets in a root sand bottom. I set the anchor following our normal back down procedure then dove in to view the results. Looked kind of half set. So I instructed my wife to back down easy and increase the revs to 2200. I dove down to get a close up just in time as she hit full throttle in reverse... I wasn't expecting that. Results.. a two meter furrow with the anchor embedded completely with roots and sand heaped up. Quite startling to watch it happen.

Tore a gaping hole in the root sand bottom in less than a second.

[JPA Cate]

"There is nothing wrong with a more casual approach when stopping for a short time in settled conditions with a benign forecast."

I know people feel this way, and it's a concept one hears a lot, but when it's only a few minutes and a cup or so of diesel, why not set it properly? there's nothing to lose. I would not want my boat to go walkabout while i was off snorkeling!

Ann

[noelex 77]

I was quite pleased when I saw a boat with a Kobra enter the anchorage. The mixture of anchors Mantus, Rocna, Kobra and Delta is a nice cross section of modern anchors.

Unfortunately, they managed to drop the anchor in small but dense patch of weed, so we cannot compare the Kobra with some other designs at this anchorage. They tied their stern to rock and in trying to get close enough, apart from letting out a copious amount of chain, they applied quite a lot of reverse. And the Kobra held in 5m @ 8:1.

You can see the Kobra was just dropped on the edge of the weed patch. It moved a few feet back and encounted this weed clump. The Kobra has not penetrated the substrate at all. In fact I am not even sure it is even touching the bottom (ignoring the weed).

This sort weed performance can be very deceptive. The thick clump of weed will hold a suprising amount of force. However, it will not hold in strong wind. Anchors can achieve a reliable performance in moderate wind just with this sort of grip on the weed itself. This lulls the owners into thinking the anchor is performing well in weed when in reality it has little hope of holding in strong wind.

A good weed anchor has a sharp thin tip that will slice through the weed into the substrate below. In this sort of weed it is a difficult task, which is why thick weed remains the Achilles heel of new generation anchors that are otherwise so versatile.

[noelex 77]

This was the other side of weed the Kobra had snagged. You can see the large area of sand that was only a 5-6m away from where the Kobra was dropped. If the water is clear, looking at the bottom and judging where to drop is important.

It is surprisingly hard to drop an anchor in a precise spot. It needs coordination between the bow and helm. In this case there was a large sand area that could have been used, but in some cases there is only a small clear patch. Allow some distance for the anchor to set so drop on the upwind side of the clear zone. With a quick setting anchor you can anchor in a clear patch only a couple of metres in size. With an anchor that needs a long distance to set the clear area needs to be much larger.

Note the chain is not lying on the bottom. This is just due to the elevation of the weed bed. The anchor is towards the bottom of the picture and the boat towards the top.

In some cases local elevation of the chain like this from rocks, debris, or weed (often the substrate is raised because of less erosion on weed bed)
Here are the photos showing the chain lifting off the bottom. The chain is not rising to meet the boat, but rather is being lifted by the weed bed. The boat is towards to top of both photos:

[noelex 77]

This was a Rocna dropped by a private cat. With their shallower draft they snuck in a bit closer to the beach and anchored in 5m @ 5:1.

The setting distance is bit hard to pick, but it was about five feet. Slightly longer than normal for this anchor, but still dramatically less than the convex plow anchors.

Once again in this anchorage the anchor is not doing quite as well as it would normally do. There is more heaping up, a slight list and the fluke is not completely buried. It is still an OK set.

[Ocean Girl]

I've been diving the anchor as soon as brian drops it and pays out to the snubber. What we observed it that the engine in reverse has very little effect on the anchor until it reached 2500-2600RPMs. At 2000RPMs the chain is lifted about 50 feet shy of the anchor.at 2300, still not chain lift. Then at 2500 I start to see chain lift, 2600, the anchor digs in.

This pic is of the anchor when first dropped and boat has drifted down wind and stopped with nose to the wind. It is just sitting on top of the seabed. We have about 10-12 knots of wind. Boat is being held by the 75 feet of chain.

We have a 45 LB Manson Supreme with 3/8 BBB chain.