Sarca Excel

[JonJo]

[QUOTE=JonJo;1159699]Noelex,



But the evidence presented (and its not unique) is that even in less weedy areas convex anchors will hold that weed in the fluke bowl - and reset is impossible (without cleaning it out).

unquote

Fundamental error here, my fault entirely

For convex, should read concave.

My apologies.

[JonJo]

Originally Posted by noelex 77

Anchors like the Rocna and MS certainly pull up some mud/sand on retrieval. If its been windy it sometimes looks like half the seabed is coming up.
"Are you trying to make the anchorage deeper" has been shouted in jest from other boats sharing the anchorage.

If I have not had chance to dive on the anchor, I always find it reassurg to see a whole lot of bottom come up, as it shows the anchor was deeply buried.

However, the premise that this will cause problems when resetting is flawed. If you dive and watch modern anchors reset with a change in wind direction they remain buried. They swivel or shuffle around. They do not break out drag across the seabed and reset.

In any substrate once an anchor starts dragging the chance of it catching is slim. In weedy locations a dragging anchor will be retrieved with a ball of weed that is large enough that it can obscure the whole anchor. This is true of all anchors, even the humble CQR.

When setting the anchor in weed its very important to avoid putting any pressure on the anchor untill a reasonsable scope is reached. If the boat is moving backwards faster than the anchor chain is deployed it will never set in weed. It's also very beneficial to have an anchor that sets quickly, which is one of the major improvements in the new generation anchors.


The modern concave anchors are a great improvement in weedy conditions over the older convex anchors. I have not used the Excel so I cannot comment if this is an exception to the rule.

Noelex

Under 'normal' wind changes the yacht drifts round slowly (or the wind direction changes slowly) and the anchor shuffles round. In such conditions you can dive on an anchor.

Maybe try anchoring in a tidal river? Anchor do not shuffle round, the yacht at one time is at 0 degrees, the tide changes and the yacht slowly drifts down, then as the tide strengthens - sometimes at 5 knots the load increases. The anchor sommersaults, along with its clod of seabed (well, river bed actually). For those who know Hunters Passage, same change of tide - 180 degrees. Fierce tides. Mersey River, at Liverpool, UK, fierce tides. But you do not need a tide, fierce tropical storms - if the cell passes right over, 180 degree wind shifts. Here in Oz, Southerly Busters, the predominately northerlies dies, suddenly turn (in about 20 minutes) to 25 knots from the south, not enough time to shuffle.

This idea that anchors shuffle is correct, but it has a time factor - thunderstorm cells don't allow time.

In Australia, and in the UK, yachts have been banned from anchoring in some locations (eg Hole in the Wall, Jervis Bay) that have been used by sailors for generations because the act of anchoring is destroying the seabed. Hauling up lumps of seabed, sufficient to enjoy the jeers from others, is not going to endear yachtsmen to the environmental lobby. This is not a size thing, your anchor Noelex, must be a monster (if its a size or two too big as recommended).

You have said you carry an anchor to meet most circumstances and seabeds. I can see a few area where I might be a bit uncomfortable. However I do now see why you have an anchor oversize.

[noelex 77]

I have seen violent wind changes and a good anchor still shuffles around.

At about 20 knots the anchor actually doesn't move at all. It typically stays set in the same direction, even with a 180 degree shift. At 25 knots most anchors will start rotating, but only very slowly.

Our larger anchor needs 30+ K of wind to start rotating.

5 knots of current only puts the same force on the anchor as 25-30k wind although it is dependent on the boat size.

It's easy to very this just dive and observe. It's a great way to learn about anchor behaviour.

If the anchor breaks out it is bad design, or was not set well in the first place

[Factor]

I think I am going to have to dispute this. In a wind against tide situation i have seen boats travel straight back over the top of their anchor, in effect mimicking picking the anchor up, i.e. the chain/rope goes straight past the anchor and applies an immediate 180 degree pull, I don't care what type of anchor you have, its more than a little likely that it will pop out or at least be partially pulled out.

I agree that if the boat can move in a way that the pull is "circular" then it shouldn't come out. I have watched boats however up anchor in the scenario I described above. It is thus one of the reasons I went for an anchor that had a higher chance of reset given it wasn't caked with the bottom.

As for diving, that not an option in much of the Queensland coast - small matter of Crocs.

[noelex 77]

Originally Posted by Factor

I think I am going to have to dispute this. In a wind against tide situation i have seen boats travel straight back over the top of their anchor, in effect mimicking picking the anchor up, i.e. the chain/rope goes straight past the anchor and applies an immediate 180 degree pull, I don't care what type of anchor you have, its more than a little likely that it will pop out or at least be partially pulled out.

Boats travel straight back over the top of their anchor quite often. Where I am at the moment we do it every couple of days. ( alternaternating between a north wind and south wind at this time of year)

However, there is little force on the anchor as there is still a long loop of chain.

Picking up the anchor is very different. Here you have close to a 1:1 scope which lifts the shank and pops the anchor out.

This will never happen as the wind, current reverses. There is still the normal scope acting on the anchor shank. The anchor shank never lifts.

There is no vertical force on the anchor as you pass over the top.

Even a poor design will not pop out as you pass over the top of the anchor.

[noelex 77]

This is diagram of what happens to the chain, as the boat passes over the anchor. (anchor not to scale)

You can see as the as the boat passes over the anchor there is very little force on the anchor. Importantly there is no vertical force on the shank pulling it up.
When retrieving or breaking out the anchor the situation is very different with almost a 1:1 scope lifting the anchor shank.

When breaking the anchor out after retrieving all the chain the force on the anchor is very different to the situation where the boat passes over the top of the anchor because of reversing wind, or current. Although the boat is in the same position, directly above the anchor, the force on the anchor shank is not the same.

The anchor is very unlikely to break out as the boat passes over the top of the anchor. ( the only exception is an anchor like the fisherman where the chain can catch on the opposite fluke that is sticking vertically up.)

As the chain stretches out to correspond to the new wind direction the anchor will gradually rotate around.

If it not (or minimally) set this is where it can break out, but if set, and of good design it will remain buried and gradually rotate around.

If the wind is less than 20-25k the anchor (if set) will remain in its initial orientation even if the chain is pointing in the opposite direction.

Sharks (anything other than white pointers) are OK, but saltwater crocks do discourage even me from observing the anchor. Unfortunately in a lot of parts of Australia the water is too murky to see the anchor from the the dingy even with a bathoscope.
Pity, as there is a lot to learned about anchor behaviour from simple observation.

[foggysail]

Sharks??? Crocks??? Anchor diving???

I don't know about you, Noelex

Foggy

[JonJo]

We have done some tests on anchors shuffling and sommersaulting. Up to about 150 degrees from the original set direction anchors will shuffle round, as long as the pull is not too aggressive. Beyond 150 degrees, if the anchor is well set and the pull not strong, then the anchor will not move, if the pull is strong enough the load is such that anchosr sommersaults. They, no anchor, is designed to work properly backwards, any pull at almost 180 degrees tries tobury the heel, which lifts the shank and the further the shank lifts the quicker the sommersault. However even loaded at 90 degrees - if the pull is sharp enough the anchor will pull out. This is not the sort of thing you will see when diving, because you are unlikely to be sitting on the bottom with your Scuba gear when it happens. It is easy to sit on the bottom watching when the conditions are benign (and/or predictable) , much less easy when the gust of 40 knots comes through.

But Noelex, you say you find it reassuring when you dive on your anchor and see it full of mud and weed. I find it reassuring when I cannot see my anchor - it has dived so well it and a few metres of chain have all gone. I see this with an Excel, Spade and Fortress. What I do find with the concave is that once they clog with weed they cannot dive as the diving characteristics are terminated by the clod of seabed that is wedged between fluke and roll bar - basically all you have is a big heavy weight buried in the top of the seabed (I note you ignored the environmental issues of your choice). That clod is not a sign of a well set anchor but a poorly designed anchor not working.

The design of the Spade, Excel, Fortress is such that the more you load them the further they dive, even small anchors had develop huge holds - as long as they can penetrate the seabed this will happen. Concaves will do exactly the same thing, except in seabeds such as heavy clay or with lots of organics (which might be weed or decaying vegetation) - the fluke simply acts as a huge scoop, funnels the seabed under the roll bar. The Roll bar compresses the seabed (becuase there is not enough sapce for the huge clod collected, and the clod clogs the fluke - at this point the anchor stops working as it was designed. This is why when you lift your anchor, funny how long it took you to tell us of this downside, its full of mud. Lift a Fortress, Spade Excel, they come up clean in virtually any seabed.

I watch it happening, someone with a concave comes into an anchorage, drops his anchor and sets it properly. They change their mind, lift the anchor - so as to move, and spend the next 10 minutes trying to clear the fluke. I see it in marinas, concave anchors with poorly cleaned flukes. The other anchors, if you get it wrong you lift and re -set (no cleaning). Walk round marinas, its only the concaves that will have mud on them.

[Kettlewell]

I'm not trying to pick sides in this discussion, having come in quite late, but this statement is simply not true:

Lift a Fortress, Spade Excel, they come up clean in virtually any seabed.

I have personally lifted a Fortress that brought up a huge clod of mud and grass and there was no way that thing would bite in again until cleaned, and I have personally witnessed a non-holding Spade anchor pulled up with an enormous ball of weed and mud completely obscuring the blade part of the anchor. There are certain bottoms that have a certain consistency that just plugs up in a scoop or blade type of anchor.

[downunder]

Originally Posted by Factor

I think I am going to have to dispute this. In a wind against tide situation i have seen boats travel straight back over the top of their anchor, in effect mimicking picking the anchor up, i.e. the chain/rope goes straight past the anchor and applies an immediate 180 degree pull, I don't care what type of anchor you have, its more than a little likely that it will pop out or at least be partially pulled out.

I agree that if the boat can move in a way that the pull is "circular" then it shouldn't come out. I have watched boats however up anchor in the scenario I described above. It is thus one of the reasons I went for an anchor that had a higher chance of reset given it wasn't caked with the bottom.

As for diving, that not an option in much of the Queensland coast - small matter of Crocs.

You should be pretty safefrom crocs in Moreton Bay.

[foggysail]

I agree with Cotemar, not because I like his horses but because of my personal experience with plow anchors, specifically the Delta.

And Deltas were once looked upon to be the salvation over the original old plow, they are not. My faith in the Delta plow was strong, I resisted the march to the Rocna when it dominated these forums. So much so that when my 55# Delta failed, allowed my boat to follow the wind when I preferred it to follow the sun, I upgraded to an 88# Delta knowing (I thought) I had the anchoring problem solved. I DID NOT!!!!

I finally got fed up with the bull $*** plow style rhetoric, purchased a new 80# Manson Supreme and this time, moved my anchoring problems to the past. I now sleep at night without constantly jumping up to see how far we plowed. If your happy with a plow------

Foggy

[Factor]

Originally Posted by foggysail

I agree with Cotemar, not because I like his horses but because of my personal experience with plow anchors, specifically the Delta. ...

Once again - the delta is not the Excel and not very much like it. The excel is not a plough, its a burying anchor. Honestly again I will say there are a number of good modern anchors around and the excel is one of them.

I hear the echos of Craig Smith

[Cotemar]

Originally Posted by Factor

And these are all exactly the same - cause they have a roll bar and/or might be concave

Concave is a good thing. It stops the nasty plowing.
The horses would stop if they had to pull a Concave anchor

Super Sarca is a nice looking anchor and looks to be a bit flatter, so looks to be a better design, not just a knock off of the old Plow design.

The only gripe I have with any anchor that has that long slot on it is that no one really uses that slot, so why weaken the shank with that thing.

[JonJo]

Someone did make the comment of slots in shanks and appeared to demonstrate they had not bothered to look at them in any detail.

If you compare the amount of steel in a Rocna shank and that of the Supreme you will find that for similar weights of anchor they both use the same thickness of steel plate. The Supreme uses a 800 MPa steel and Rocna uses something, which last reported was less strong - but now its anyone's guess. But on the assumption the steels were similar then the Supreme shank will be stronger than the Rocna, because it has more width. More steel (more width in this case) for the same thickness - stronger section. Buying the Supreme with its slot and you get a stronger anchor (the opposite to what might be expected). Given that the Supreme uses stronger steel then its a win win. I cannot comment on the Boss, I have not checked and I'm not so arrogant I can devine its measurements by looking at an image - I know some people can tell what sort of steel is used, how it performs and the person who made it just by looking at a picture but I lack that skill and arrogance.

For both the Boss and Super SARCA you can lock the shackle point off with a Nyloc nut - leaving the slot ready for the time you need it (say if you are anchoring near rock, coral or with ground chains etc). In fact slotted shanks would be ideal in the Med for anchoring bow onto a quay and when a stern anchor is deployed where there are lots of ground chains about as the slot would allow easier retrieval. Noelex - you might shed light on this (as you are there), though your posts seem to suggest that you and we have something in common - we prefer to anchor.

[noelex 77]

Originally Posted by JonJo

We have done some tests on anchors shuffling and sommersaulting. Up to about 150 degrees from the original set direction anchors will shuffle round, as long as the pull is not too aggressive. Beyond 150 degrees, if the anchor is well set and the pull not strong, then the anchor will not move, if the pull is strong enough the load is such that anchosr sommersaults. They, no anchor, is designed to work properly backwards, any pull at almost 180 degrees tries tobury the heel, which lifts the shank and the further the shank lifts the quicker the sommersault. However even loaded at 90 degrees - if the pull is sharp enough the anchor will pull out. This is not the sort of thing you will see when diving, because you are unlikely to be sitting on the bottom with your Scuba gear when it happens. It is easy to sit on the bottom watching when the conditions are benign (and/or predictable) , much less easy when the gust of 40 knots comes through.

The nice thing about the Med (or some of the South Pacific) is the water is so clear. In most anchorages from the surface snorkelling or with a bathoscope you can see the anchor clearly 15m (45 feet down). I can free dive down to the bottom for a closer look if needed.
It is a great laboratory for examining anchors.

The modern anchors do not somersault. ( the only exception is the Fortress. I think the Fortress is a great anchor, but it does display this weakness.) It is very difficult to simulate the forces on an anchor particularly with a change of direction. With a real boat the force is much more like a series of jerks, as the boat yaws around.
I can only put our difference in observation down to the limitations of simulation, involving the more steady pull of tractor, or car winch etc, which I presume is how you are making the observations.
Try diving and observing what is really happening. Strong wind does not have much effect on the comfort snorkelling.

Originally Posted by JonJo

But Noelex, you say you find it reassuring when you dive on your anchor and see it full of mud and weed. I find it reassuring when I cannot see my anchor - it has dived so well it and a few metres of chain have all gone. I see this with an Excel, Spade and Fortress.

I agree, the deeper an anchor is buried the better. All designs of anchors disappear completely, but some do it much better than others.

When diving I often get to see a large number of different designs in similar substrates and the degree of set is useful in evaluating the anchor performance.
I don't share your pessimism about the roll bar inhibiting the diving, or burying of the anchor. This does not equate to what I have observed. Roll bar anchor bury very well

Concave anchors offer more resistance than a convex anchor when buried an identical amount with the same blade area.
This is very noticeable with the Delta anchor and the Kobra which can be well set and buried, but slowly drag. ( It looks like a worm or mole burrowing under the sand you cannot see the anchor at all, just the sand rippling and bulging above the anchor).
I would be interested to try an Excel to see if it suffers the same problem.

My hypothesis is that it modern anchor designs set, and remain set, much better than their older cousins, but convex designs don't offer as much resistance as a concave blade of equal area. this limitation only shows up in anchorages with a reasonably soft substrate that does not get much firmer as you go deeper. Fortunately these soil conditions are not common, but they are seen in some anchorages.

The theory is based on observation, but it does have some justification if you look at drag coefficients in fluid dynamics.

I have not used an Excel but my personal list of best to worst anchors after watching how they perform in the real world shows a surprising consistency based on the curvature of the blade (with only a few odd exceptions like the XYZ anchor).
The anchors grade from concave blade, best, then to flat blade, with convex blade having the worst performance.
There have been few modern convex bladed anchors so perhaps the Excel is the exception that proves the rule. Time will tell.

(Please bear in mind these are only personal observations /opinions about of lumps of steel that sit on the bottom of the sea. )