DIY- make your own anchor

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John the kiwi

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I have been somewhat dissatisfied with the setting performance of my CQR plough anchor on my 26 ft Trailer Sailor.
Looking at the options it seems that the modern pattern anchors are the way to go.
However, when I look at the prices and what you get for your money i do recoil a bit.
I am a mechanical engineer and trained in welding in my younger days, and it seems that even allowing for use of higher strength steels, the price markups are somewhere between extreme and outrageous.
Have any forumites built their own modern pattern anchor, and if so do you have tips and or advice?

Thanks in advance
 
scruff said:
Buy
Dimension
Return
Reproduce.
(then possibly drag!)
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;) Ha haha. Good response, though you forgot the metallurgical analysis step to ensure the copy is built to same spec as original.!!
Not so simple to determine the steel qualities from simple examination.
A design based on High tensile steel may be a bit bendy in bog standard mild steel.
Is this the case? I don't know, which is why i posed the question. I may be cheap, but i don't want to unnecessarily risk my boat.
Cheers
 
There is a boat show in Auckland, I think next week (Hutchwilco?). Go and have a look, there might be some anchors on special. In any event you could tell us what's going on there.

Jonathan
 
John the kiwi said:
;) Ha haha. Good response, though you forgot the metallurgical analysis step to ensure the copy is built to same spec as original.!!
Not so simple to determine the steel qualities from simple examination.
A design based on High tensile steel may be a bit bendy in bog standard mild steel.
Is this the case? I don't know, which is why i posed the question. I may be cheap, but i don't want to unnecessarily risk my boat.
Cheers
Click to expand...

It's rather more complex than that. Rules for anchoring gear limit carbon content to less than 0.23 % to prevent the formation of martensite that would be a stress raiser. This means that no conventional high tensile steels can be used, for anchors, chain or connectors. The way around that is either to use boron-based steels, e.g. bisplate, or to use HSLA steels ( high strength low alloy) the latter is widely used for construction nowadays, although I don't know how you would buy it in very small quantities.

The other answer of course is to make everything so massive that it won't bend but this conflicts with the modern understanding that maximising tip weight improves set.
 
vyv_cox said:
It's rather more complex than that. Rules for anchoring gear limit carbon content to less than 0.23 % to prevent the formation of martensite that would be a stress raiser. This means that no conventional high tensile steels can be used, for anchors, chain or connectors. The way around that is either to use boron-based steels, e.g. bisplate, or to use HSLA steels ( high strength low alloy) the latter is widely used for construction nowadays, although I don't know how you would buy it in very small quantities.



I have, in the past, made several anchors of various designs, (Fisherman, CQR, Danforth), using bog standard mild steel, and then having them galvanised. Mild steel doesn't give you any nasty surprises. If you think that a part might bend, just use a heavier section.
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I sail in Turkey, where there are plenty of locally made copies of the Bugel anchor. Probably all mild steel, but the design allows easy fabrication because the only part that is not just flat plate is the roll bar.
 
In a lot of modern designs reducing shank weight helps with the balance and set of the anchor.

Making the shank thicker would reduce the performance.
This is why some new generation anchors use stronger steels, or a complex constriction in their shank design.

Making the shank out of a fabricated construction may be a useful option to consider a strong lightweight shank could be constructed out of mild steel. The extra labour involved is the major deterant to using this commercially.

The other option to consider are going up a couple of sizes or more, for your sized boat. The extra material cost will be minimium and a large anchor is less likely to bend. The size will help compensate for any design inefficiencies.

The Bugal is a good performing, very simple design, that is worth considering for home constucion, on the other hand there are many cheap commercial copies that will not be much dearer than making your own.
 
John the kiwi said:
;) Ha haha. Good response, though you forgot the metallurgical analysis step to ensure the copy is built to same spec as original.!!
Click to expand...

Even that won't always help. We've seen in the past that at least one manufacturer (Rocna, to name names) was happy to boast about their high spec materials, but to then be shown to be using lower spec steels.
 
Norman_E said:
I sail in Turkey, where there are plenty of locally made copies of the Bugel anchor. Probably all mild steel, but the design allows easy fabrication because the only part that is not just flat plate is the roll bar.
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The Bugel is an odd one. I understand that it is correctly called a WASI, the original designer (although I may have these the wrong way around). The plans were made available to anyone who wants to build one. If I was going to make an anchor this is the way I would go - no experimenting to find something that works, just build one that works very well.
 
Of course you can make your own anchor. The three obvious elements are the Design, the Material and the Fabrication. As you are a Mechanical Engineer you should be able to manage each of these elements separately and then integrate them to produce the final product.

I suggest that the design considers the advantages of not welding the arm to the blade directly but cutting a slot through the blade and passing through the arm and then welding it from underneath, thus the force when pulling is distributed and does not pull solely on the weld seam; food for thought.
 
"Cutting a slot through the blade and passing through the arm and then welding it from underneath, thus the force when pulling is distributed and does not pull solely on the weld seam; food for thought."

I have built several danforth types for use as a lunch hook of no special materials used, but I have made one simular to one of the new type designs and welded the stock to the blade as described above.

Not used it in a real blow yet but I do have a copy of a bruce anchor not made by me as backup

As can be seen in this pic.
 
vyv_cox said:
The Bugel is an odd one. I understand that it is correctly called a WASI, the original designer (although I may have these the wrong way around). The plans were made available to anyone who wants to build one. If I was going to make an anchor this is the way I would go - no experimenting to find something that works, just build one that works very well.
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WASI sell the stainless version, the original Buegel was designed by Rolf Kaczirek. He specified "RSt 42.d." steel (whatever that is). The reason why so many copies exist, apart from the simple design, is that Mr. Kaczirek never had it patented due to cost it seems. Most galvanized copies use "St 37" btw.
 
Lots of people make their own anchors for various reasons. Usually its to get a better product for your money and to overcome any design faults that manufacturers can not avoid.
Modern anchors are far superior to your old CQR. What you have to decide is how you are going to store this anchor, how much space you have in an anchor locker etc. Rocknas or Spades are bulky. Manufacturers will have templates on their webpages so prospective customers can make timber versions to see if they fit. What you will notice with these templates is the geometry is almost identical between all the main players. The angle the blade meets the shank, the length of the shank and the sharpness of the blade determines how good they hold. Also what method they use to place the anchor on the bottom in the correct position to actually dig in. Use Youtube to watch examples you are interested in.
My yacht is 30 foot long with an anchor well in the fore deck, appropriate sized Rocknas or Spades would not fit. The Ultra would have been my choice but for the same money I could have bought two good used cars! I built a Ultra look alike out of SS plate and tube with the keel more like the Spade. The shaft is made from 15mm and 20mm tube skinned with 3mm SS plate and looks suspiciously like a rocna shank. The blade and keel is made out of SS plate and the keel filled with old anodes and lead. Before the lead was added it weighed 8 kilos, 13 kilos finished. Because of the hollow shank and the angle of the keel on the bottom and the weighted tip, it sinks to the bottom perfectly [I use 8metres of 8mm chain and a nylon rode]. It is also easy to carry. If I had bought all the material instead of finding it about the workshop I would have spent about $100. Used a lot of arc welding rods but they are cheap these days.
 
Ignore the doubters go for it... some one had to start making copies of all the other brand, from history heresounds like you are over qualified!
 
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