Open Source Anchor Project

[noelex 77]

Thanks for the photos.

If you at the Raya fluke you can see some of the features I mentioned. The tip has added weight. The back of the fluke is a light as possible to the extent they have added rails along sides. These stiffen the back of fluke without adding much weight. (They also help in orientation when setting).

The shank has not the hollow tubular construction of the Spade which was designed to reduce the weight of the shank, but the Raya was an attempt to anchor simpler and cheaper than the Spade.

On the non roll bar anchors the shank does need to be tall, but the lighter the shank the better the performance.

Despite these steps the Raya was never a commercial success. It it always difficult to know how much of this was due to poor marketing, pricing etc rather than poor performance, but the three designs (Oceane, Sword and Raya) in relative quick succession suggest to me there were aspects of the design that were not working.

This was from the most talented and experienced anchor designers that we have seen in recent years. To try and develop a very simple anchor along the same lines with no welding and a uniform thick fluke I don't think will perform well.

You can make a simple home made anchor that's works reasonably, but it needs to be a design compatible with those goals.

Good luck with whatever you decide. I am only offering my 2c worth. Not that long ago the CQR was the best anchor design and it was only radical thinking from determined individuals that produced improvements.

[Shawn67]

"but the three designs (Oceane, Sword and Raya) in relative quick succession suggest to me there were aspects of the design that were not working."

I think the primary difference between the Oceane and Sword was in trying to make the anchor more compatible on bow rollers. From their to the Raya it looks like it was a bit more optimized in how it was built. The rails face in the opposite direction and also work out to be exactly the same size as the added thickness in the point. Interestingly the first posts on the Raya had those rails in the opposite direction.

As far as the Raya if you go back on the forum there were lots of interesting discussions about it. The problem was not many wanted to be early adopters purchasing directly from Brazil without any independent tests or local distributors. Around the time positive reports were coming in is right around when Ancora Latina closed up shop... possibly due to Alain's death.

Shawn

[Delancey]

All-right, let's build some strength into our super awesome through-hole cantilever joint to make it resist bending side to side.

For our purposes we are going to say that the metal we're working with is pretty well balanced in tensive and compressive strength, something like mild steel. We want to make a joint that is going to approximate the strength of a welded connection.

Because this metal is isotopic and balanced in strength, no matter how strong we make this joint, it is still going to bend just past the joint because that's just how it goes. For our purposes we are talking plate or bar, not tubing. When we talk solid, the only way we can get stiffness is to add thickness.

Thickness matters to the strength of the joint as well, deeper is stronger. For our discussion we are going to keep it simple and join two plates of equal thickness, call it 1/2". In the first view we see a zero clearance joint which relies on perfectly mating surfaces. If we bent it, it would bend right at the corner. Zero clearance is pretty hard to do, besides it's not as strong as a weld.

The reason it's not as strong is because it's not as deep. Ignore the fact that I was lazy and didn't show a weld on the backside as you would do if you were really welding an anchor shank to a fluke.

The weld on the backside is immaterial to the fact that if we bent it, it would still bend just past the joint. The weld is stronger than the zero clearance joint because it is thicker by the depth of the weld fillet but that doesn't change the strength of the metal itself.

If we were to add a shoe on the bottom of our fluke and we bolted it so it couldn't move side to side, it would be a lot stronger than the weld because it's thicker. Regardless, if you bent it, it would still bend just past the joint same as always.

Maybe you're uncertain and you want to make it even stronger. Ok, let's make it deeper still. Let's bolt on some angle, maybe 1/4" x 1" would do the trick. Maybe it should be 1/2" thick who knows, but one thing is for sure, if we bend it, it will bend just past the joint. 1/4" is probably good enough.

Now we all know I am a bit stingy, is that so wrong? It's a small planet after all. To help out in a small way we can sandwich the fluke with two pieces of angle using just two bolts. If you bend it one way it bends at the edge of the angle, bend it the other way it bends at the fluke. Either way it will bend if we force it too much, the only way we can make it stiffer is to make it thicker.

I guess since we're doing such a good job saving the planet by making this damn anchor we could maybe splurge and bolt the two angles on either side using four bolts, they don't really have to be very big anyway. While we are at it with this whole angle business I suppose we could include a locator hole through the angles and the shank for our chopstick.

Angle is everyone's bitch, whenever anyone has a problem they throw angle at it. Let's show her some respect and put a nice radius on her corners, won't that be pretty? Or maybe we should treat her to a night off, where's that lazy layabout roll-bar?

He's only doing us any good when we land upside down, the rest of the time he just sits there on the couch watching TV. Since he is the tallest, he would be the strongest of them all.

You see this in Peter Bruce's original design and a couple of the knock-offs too like the SARCA and the Knox. It means we have to make a connection between the shank and the roll bar but it's an option we can keep on the table. It's good to have options....

[Delancey]

Might be better to run the angle out past front and back edge of the shank instead is stopping it short. That is if you were going to do angle and not a shoe. Depends on the fluke thickness too. BTW how we coming on those dimensions for the plate thicknesses? Anybody?

[Delancey]

Originally Posted by noelex 77

I don't want to sound negative but I do not see how you are going to get enough lateral support with a simple slot cut in the fluke.
An anchor has to resist a force at right angle to the fluke. The spade does this with a welded box construction.
The Kobra does it with this (complicated) system. (See photo) Perhaps I misunderstanding what you are proposing, but the shank has to resist more than a straight pull. I cannot see a simple slot cut into the fluke doing that.

Not exactly sure how this fits together but yikes! Seems to me like the distance between fasteners or the overall depth of the connection is as much about resisting the downward rotational moment trying to separate the fluke from the shank than it is about side to side.

Looks like they are trying to do this all inside the depth of the ballast so that it looks cool from the outside for marketing photographs.

Comparatively, with our through-hole cantilever the distance between bearing points can be as wide and therefore as strong as we want. Regardless of this, the shank is only going to be as stiff as its thickness, making the joint any stronger is a waste of effort.

[noelex 77]

Originally Posted by Shawn67

As far as the Raya if you go back on the forum there were lots of interesting discussions about it. The problem was not many wanted to be early adopters purchasing directly from Brazil without any independent tests or local distributors. Around the time positive reports were coming in is right around when Ancora Latina closed up shop... possibly due to Alain's death.

Shawn

I agree Shawn it is very hard to evaluate these anchors that sold in small numbers. No one wants to buy them until they are "proven". There really is not a lot of data on the Raya to draw accurate conclusions. (Which means it could be very good)

The Oceane was tested in the big multimaginze 2006 test. The results are below. As you point out the Raya is different and I suspect better. The results do highlight one of the difficulties with this sort of non roll bar, non balasted tip anchor like the defunct Oceane, Sword and Raya. They have some inconsistency in their performance, sometimes setting very well at other times not at all. It will be interesting to see if the current Manson Boss has solved this limitation.

If you look at the results of the Oceane in the test you can see that overall it has done worse than the very simple Bugel. My feeling is a simple homemade anchor
with the same characteristics (non roll bar, non balasted tip) further simplified with no welding the use of flat plate, uniform thickness, fluke with limited testing and development is not likely to fare better than the Oceane.

Non roll bar, non balasted tip anchors are the Formula 1 of the anchor world. They are finicky and sensitive to small changes in weight and balance. They can perform spectacularly well, or blow up after the first bend.

[noelex 77]

Originally Posted by Delancey

All-right, let's build some strength into our super awesome through-hole cantilever joint to make it resist bending side to side.

That looks much better to me.

It seems you are aiming for a non welded bolt together construction. If this is the case I would consider aluminium more seriously for both the fluke and shank. The much lower density means the weight in the shank and heel of the fluke is less of problem. One great difficulty with aluminium construction is how to provide some ballast in the toe. On commercial anchors this has been done with a complicated welded, lead filled, ballast chamber.

A simple idea would be use bolt on zinc ballast. This would not need to be sealed. Unlike lead, zinc will not corrode the aluminium if both are in contact with seawater so there is no need for a sealed chamber. Zinc is quite easy to mould and the zinc would be non structural just adding weight. The zinc would slowly corrode (not the aluminium structure) so you would need to bolt on a new tip ballast every couple of years, but it would be easy to mould a few spares. The zinc would protect the aluminium from electrolytic corrosion from the (probably SS) bolts. There is plenty of discarded zinc anodes around boatyards that could be melted down so the balast material would be free. You could experiment with different sized and shapes zinc ballasts to optimise performance.

Aluminium is easier to work with. The material cost is higher but the fluke and shank could be cut from a single piece of the same plate thickness without any undue concerns about an overly heavy shank. Very sharp cutting edges can be incorporated into the leading edges, further enhancing performance. The extra construction step of galvanisation is not needed.

[martinworswick]

how about having 2 shanks instead of 1?instead of 1 on the centreline you could have 2 with the same slot in style attachment located maybe half way between the centreline and the outside of the fluke,attached at the eye,this would,i'd imagine be stronger when a sideways force is applied,it would also give it 2 'feet' to sit on giving a better angle for the pointy bit to dig in.maybe having 2 shanks would affect its ability to dig in though?thoughts?

[noelex 77]

Potentially a good idea. The large oil rig anchors use this. Two thinner shanks should not resist digging in much more than one thick one. The webbing between the two shanks is orientated at the same angle as the flukes, so there are a series of "mini flukes" along the shank, but it is difficult to see how this could be done easily without welding. The separation would need to narrower than the bow roller width.

[martinworswick]

exactly what i was thinking,only a simplified version-without the fins so no welding and keep it so it still slots together,i forgot about the bow roller,i'll have a think.......

[foolishsailor]

Originally Posted by noelex 77

That looks much better to me. If you aiming for medium/high performance anchor I would prefer to see the the fluke thinner say 1/4 inch material with the toe of the fluke forward of the shank having some extra material say 2x1/4 inch plates for weight distribution. It seems you are aiming for a non welded bolt together construction. If this is the case I would consider aluminium more seriously for both the fluke and shank. The much lower density means the weight in the shank and heel of the fluke is less of problem. One great difficulty with aluminium construction is how to provide some ballast in the toe. On commercial anchors this has been done with a complicated welded lead filled ballast chamber. A simple idea would be use bolt on zinc ballast. Unlike lead this would not need to be sealed. Unlike lead, zinc will not corrode the aluminium if both are in contact with seawater so there is no need for a sealed chamber. Zinc is quite easy to mould and the zinc would be non structural just adding weight. The zinc itself would corrode (not the aluminium structure) so you would need to bolt on a new tip ballast every couple of years, but it would be easy to mould a few spares. There is plenty of discarded zinc anodes around boatyards so the balast material would be free. Aluminium is easier to work with. The material cost is higher but the fluke and shank could be cut from a single piece of the same plate thickness without any undue concerns about an overly heavy shank. Very sharp cutting edges can be incorporated into the leading edges, further enhancing performance. The extra construction step of galvanisation is not needed.

Another benefit of aluminium is you can work it with basic carpentry tools. Table saws, jig saws, drill presses etc.

I have worked with people melting zinc as well - dead easy to do safely and mold making is a snap.

These two material choices would make the building of am anchor possible even on a deserted island. All you need are spare bolts, spare anodes, boats generator, and a bottle of propane or even a well designed fire...

[Delancey]

Originally Posted by martinworswick

how about having 2 shanks instead of 1?instead of 1 on the centreline you could have 2 with the same slot in style attachment located maybe half way between the centreline and the outside of the fluke,attached at the eye,this would,i'd imagine be stronger when a sideways force is applied,it would also give it 2 'feet' to sit on giving a better angle for the pointy bit to dig in.maybe having 2 shanks would affect its ability to dig in though?thoughts?

I thought about this early on, since none of the other design thieves I mean anchor designers haven't copied it means it either has active patents or it is just not practical to adapt to a yacht anchor. As Nolex mentions there is the bow roller issue.

[Delancey]

Originally Posted by noelex 77

I agree Shawn it is very hard to evaluate these anchors that sold in small numbers. No one wants to buy them until they are "proven". There really is not a lot of data on the Raya to draw accurate conclusions. (Which means it could be very good)

The Oceane was tested in the big multimaginze 2006 test. The results are below. As you point out the Raya is different and I suspect better. The results do highlight one of the difficulties with this sort of non roll bar, non balasted tip anchor like the defunct Oceane, Sword and Raya. They have some inconsistency in their performance, sometimes setting very well at other times not at all. It will be interesting to see if the current Manson Boss has solved this limitation.

If you look at the results of the Oceane in the test you can see that overall it has done worse than the very simple Bugel. My feeling is a simple homemade anchor
with the same characteristics (non roll bar, non balasted tip) further simplified with no welding the use of flat plate, uniform thickness, fluke with limited testing and development is not likely to fare better than the Oceane.

Non roll bar, non balasted tip anchors are the Formula 1 of the anchor world. They are finicky and sensitive to small changes in weight and balance. They can perform spectacularly well, or blow up after the first bend.

I pretty much agree with you there. Prolly chasing the Raya, Sword, Oceane thing is a red herring. I think we should give ballasted self righting a look to see if is even remotely possible, but early on I figure we would be ending up with a roll-bar type.

[Delancey]

Originally Posted by noelex 77

That looks much better to me.

It seems you are aiming for a non welded bolt together construction. If this is the case I would consider aluminium more seriously for both the fluke and shank. The much lower density means the weight in the shank and heel of the fluke is less of problem. One great difficulty with aluminium construction is how to provide some ballast in the toe. On commercial anchors this has been done with a complicated welded, lead filled, ballast chamber.

A simple idea would be use bolt on zinc ballast. This would not need to be sealed. Unlike lead, zinc will not corrode the aluminium if both are in contact with seawater so there is no need for a sealed chamber. Zinc is quite easy to mould and the zinc would be non structural just adding weight. The zinc would slowly corrode (not the aluminium structure) so you would need to bolt on a new tip ballast every couple of years, but it would be easy to mould a few spares. The zinc would protect the aluminium from electrolytic corrosion from the (probably SS) bolts. There is plenty of discarded zinc anodes around boatyards that could be melted down so the balast material would be free. You could experiment with different sized and shapes zinc ballasts to optimise performance.

Aluminium is easier to work with. The material cost is higher but the fluke and shank could be cut from a single piece of the same plate thickness without any undue concerns about an overly heavy shank. Very sharp cutting edges can be incorporated into the leading edges, further enhancing performance. The extra construction step of galvanisation is not needed.

I agree, aluminum has a lot going for it. Now that we don't have a weld it looks a lot better due to it being readily cuttable with standard wood working tools. You can even carve it with a chisel.

Two thirds the weight of steel means a bigger fluke area for the same weight. I've never seen or heard of an aluminum Bügel, can't see any reason why not.

My only reservation is that I don't think it is as widely available as mild steel and it tends to be more expensive. That said not a big deal for one design adaptable to two different metals, we can do that.

Aluminum Fun Fact -aluminum oxide is so hard and strong they make sandpaper from it. If you want you can sand that rusty old steel anchor you have with some aluminum and make it shiny again!

[Delancey]

Hello? A anyone? Are you out there? We need some material thicknesses for 20kg/44lb anchors and a no-tech way to bend plate. A little help here?