Open Source Anchor Project

[goboatingnow]

Originally Posted by Delancey

Look, I totally agree that MIG and TIG are more common than they used to be and yes you can stick weld both aluminum and stainless. I wouldn't agree with any assertion that either material or the resources and skills necessary to work with them were commonly available, therefore they don't make sense to me as the material of choice for the OSA. Do the groundwork design in mild steel, scale it out to other materials later.

I think your bolt-together idea is fantastic!!!! Seriously worth looking at. I would take it a step further and suggest rivets as an alternate fastening. This type of construction was suitable for building the Empire State Building and it's still standing all these years.

Of course it means a second material besides the plate and addition of the fasteners, but it eliminates welding. It is also fairly easy to deform angle as would be required to make the connection between the shank and the halves of the fluke, be they convex or concave.

A little investigation and what do you know? From the Pitcairn Island tourism website- "Though Fuel may not be available and water can be very scarce in the summer months, the necessary skills of the islanders, mean that many boat repairs can be undertaken, including some welding of aluminum and stainless steel. The going rate is usually around US $12.00 per hour and for that you get a lot of effort." Sail to Pitcairn | Pitcairn Islands Tourism

Mind you the $100000s to get there can be ignored of course.

Dave

[Mirar]

Hello all, Just to add some real time numbers on the cost of building your own new age anchor. I just finished an anchor building project for a friend and myself, three "modern design" units, 135#or 61kg . These are similar but slightly different to a lot of conical fluke styles available today. They were made with high tensile 1" (25 mm) stocks and 3/4" (18mm) flukes. I had them all nested from the plate, plasma cut and professionally welded to a very high standard. Total cost minus galvanizing was 600 U.S each.
Although I am a reasonably good welder I splurged to have it done in a more controlled manner (pre-heating, heat stick indicators etc) so that added about 200 bucks to each anchor.As far as the design, it wouldn't make much difference to cost what pattern is followed, a bad design would be about the same.
cheers, Greg

[Delancey]

Originally Posted by marujo.sortudo

We'll, here's a crazy thought... What about an anchor that uses wood's buoyancy to orient the anchor. Traditional Chinese anchors did this, and a more modern anchor that was a bit of a marketing flop albeit with good and bad results in anchor tests used a similar concept. Look up the Hydrobubble if you're not familiar with it. Some pieces of wood lashed or bolted in the right location could remove the need for a roll bar, perhaps? Similar in concept to the lead weight and hollow shank of the Spade, and very easy and cheap to fabricate anywhere (if it works

Opps, when I first read your post I missed your reference to the Hydrobubble, sorry.

[Delancey]

Originally Posted by Mirar

Hello all, Just to add some real time numbers on the cost of building your own new age anchor. I just finished an anchor building project for a friend and myself, three "modern design" units, 135#or 61kg . These are similar but slightly different to a lot of conical fluke styles available today. They were made with high tensile 1" (25 mm) stocks and 3/4" (18mm) flukes. I had them all nested from the plate, plasma cut and professionally welded to a very high standard. Total cost minus galvanizing was 600 U.S each.
Although I am a reasonably good welder I splurged to have it done in a more controlled manner (pre-heating, heat stick indicators etc) so that added about 200 bucks to each anchor.As far as the design, it wouldn't make much difference to cost what pattern is followed, a bad design would be about the same.
cheers, Greg

I see a 55kg Rocna lists for $1,759.99US and a 70kg Rocna for $2,439.99US right now at waste marine, both in galvanized. Thanks for sharing the info.

Do you feel like you got as good or better quality from your local guy as you would by shopping online and buying an anchor from China?

[Delancey]

Originally Posted by marujo.sortudo

We'll, here's a crazy thought... What about an anchor that uses wood's buoyancy to orient the anchor. Traditional Chinese anchors did this, and a more modern anchor that was a bit of a marketing flop albeit with good and bad results in anchor tests used a similar concept. Look up the Hydrobubble if you're not familiar with it. Some pieces of wood lashed or bolted in the right location could remove the need for a roll bar, perhaps? Similar in concept to the lead weight and hollow shank of the Spade, and very easy and cheap to fabricate anywhere (if it works

Anybody with a Mantus out there willing to oblige the forum by dismounting the roll bar and attaching a small buoy or float via a short pennant to investigate its' ability to provide self-righting?

[Shawn67]

Originally Posted by Cheechako

Why arent anchors symmetrical? ie: no matter which way it lands, no matter if it pulls out... it is always positioned to dig in again.

Isn't that basically what the bullwaga was?

If it doesn't set in deep enough it might have an issue fouling the rode on a tide shift.

Shawn

[Delancey]

Originally Posted by Shawn67

Isn't that basically what the bullwaga was?

If it doesn't set in deep enough it might have an issue fouling the rode on a tide shift.

Shawn

You know I was always so enamoured with the way the shank attaches to the flukes that I never really considered the lazy fluke factor on the Bulwagga. Being a rod inside a pipe with a cap on the end, the attachment obviates the need for swivel in your gear.

Besides being inspiration for a tattoo cliché, the problem with the lazy fluke is that it's dead weight, it doesn't do anything for you and robs you of utility.

I think we can all agree that dead weight contributes at best marginally to penetration on setting.

If that dead comes comes in the form of a cast lead weight like in a Delta of Spade, it causes drag on setting.

Regardless, once the anchor is set the dead weight contributes nothing to holding power unless you are anchoring in Jello, so why not use that weight in the shank or the fluke area where it counts?

Perhaps these are some of the reasons why the Bulwagga did not enjoy greater success. In terms of overall design I think it earns high marks for the no-swivel thing, which is huge.

Not a lot to go wrong with that joint either, you could beef it up to resist abrasion for a long life or maybe add a bushing of some sort.

I like it that is also sort of a built in stress reliever like the joint on a CQR or a Danforth, obviously not a solution for the bent shank business but I doubt there is.

[Bestathook]

May I suggest another point of view. I am a third world kind of thinker, and prefer decidedly low tech solutions. This is in keeping with your Pitcarin Island scenario.

One of my interests is to find what I want in an existing structure, and removing it. I am looking for a common steel tank or pipe, of dimension, material and shape that I can cut out the parts of an anchor with a common torch, for instance the bottom of a new generation anchor.

To be valid, the "mother" object must be common enough and be found in enough places to be relevant to many sailors. Obviously parts from something like a model T Ford may work, but must be rejected because of rarity.

In the anchor's case, the curved wall of a propane tank of an appropriate size and thickness, or shank pieces cut from a bush hog blade may be usable. Matching size to needs will be a problem here. I will have a photo of this when anchor welding travels to the top of my long, long experiment list. DON'T hold your breath!

But the essence of third world creativity is to find a new purpose for existing forms, castings, plate or other objects that are commonly at hand. The old paint can/cement dingy anchor is a classic example, both materials having a worldwide distribution.

I suspect you are thinking of something far more precise, and I am following your work with delight.

I merely suggest an additional approach for those of us with less technical ability, and more immediate need.

[Delancey]

Originally Posted by Bestathook

May I suggest another point of view. I am a third world kind of thinker, and prefer decidedly low tech solutions. This is in keeping with your Pitcarin Island scenario.

One of my interests is to find what I want in an existing structure, and removing it. I am looking for a common steel tank or pipe, of dimension, material and shape that I can cut out the parts of an anchor with a common torch, for instance the bottom of a new generation anchor.

To be valid, the "mother" object must be common enough and be found in enough places to be relevant to many sailors. Obviously parts from something like a model T Ford may work, but must be rejected because of rarity.

In the anchor's case, the curved wall of a propane tank of an appropriate size and thickness, or shank pieces cut from a bush hog blade may be usable. Matching size to needs will be a problem here. I will have a photo of this when anchor welding travels to the top of my long, long experiment list. DON'T hold your breath!

But the essence of third world creativity is to find a new purpose for existing forms, castings, plate or other objects that are commonly at hand. The old paint can/cement dingy anchor is a classic example, both materials having a worldwide distribution.

I suspect you are thinking of something far more precise, and I am following your work with delight.

I merely suggest an additional approach for those of us with less technical ability, and more immediate need.

I can totally appreciate your outlook and I hope you will share some photos of you projects here on this thread in the future. Improvisation is a skill that can be developed, but it takes effort in you're not forced into it.

The fact that a need exists is not a requirement for ingenuity. I design beautiful things for the 1% and they are mostly built by craftsman and artisans from second and third world countries. All of whom possess the creativity you are describing.

However much necessity may be the mother of all invention it is not a requirement for ingenuity. We can make ourselves more creative, it's an ability we all have as humans but I think few find both the encouragement and motivation required when provide a more effortless alternative.

[Shawn67]

"once the anchor is set the dead weight contributes nothing to holding power unless you are anchoring in Jello, so why not use that weight in the shank or the fluke area where it counts?"

They made the tradeoff of having that extra dead weight in a design to try and make sure the anchor was always in a position to set. There are certain many other designs/tradeoffs available as well.


As for myself when I bought my anchor I went with a design that tried to minimize dead weight and maximize fluke area.

Shawn

[Mirar]

Hi Delancey, Yes, I have no doubt whatever that the welding and methodology was perfect. I purchased the metal from a local industrial supplier c/w alloy certification, the welder specializes in building and repairing excavator buckets and other such heavy road building equipment. There is no way that his welds will break and I seriously doubt the stock will bend. It is a heavy anchor but considering 25 extra pounds or so is only the weight of about 10 feet of 3/8" anchor chain, it makes no sense to skimp.
regards, Greg

[Delancey]

Originally Posted by Mirar

Hi Delancey, Yes, I have no doubt whatever that the welding and methodology was perfect. I purchased the metal from a local industrial supplier c/w alloy certification, the welder specializes in building and repairing excavator buckets and other such heavy road building equipment. There is no way that his welds will break and I seriously doubt the stock will bend. It is a heavy anchor but considering 25 extra pounds or so is only the weight of about 10 feet of 3/8" anchor chain, it makes no sense to skimp.
regards, Greg

Mirar- I think that is so awesome! You are to be totally commended for possessing the open-mindedness and creativity required to understand that as a consumer you have choices, and that with a little effort you can enjoy substantial benefits by making the right one.

In addition to the economic benefit, I imagine that you enjoyed a personal benefit from you interaction with real person instead of a computer monitor. Perhaps you knew this individual, perhaps he was a friend of a friend, or maybe you found him on the computer monitor. Regardless, in the end you received a superior product by giving you money to your neighbor instead of the Chinese.

I take it from your description that you modeled your design off an existing roll-bar anchor design but substituted thicker materials to increase strength. Because the roll-bar design self-rights through geometry instead of CG, the fact that you made this change should not result in any significant compromise in performance.

Regarding weight in general, I want to state that for our purposes we are interested in maximizing our potential within a finite quantity of material. You have to set a limit.

Increasing shank thickness, for example, will increase its strength but comes at the expense of additional weight. This added strength, when considered as portion of the overall weight, comes at the expense of material that could be used toward fluke area to contribute to holding power.

Is your shank stronger, yes. Is you anchor heavier, yes. Does your anchor have the same weight to fluke area ratio as the design you modeled off of? No, it has less. Does your anchor have the same holding power as a the lighter weight anchor you modeled it from, yes. Is any of this a problem? No, not unless you don't value a relatively stronger shank and can’t accept a roll bar design which makes the center of gravity irrelevant.

With the Spade type anchor, which relies on a ballasted tip to achieve a center of gravity necessary to right itself, beefing up the shank is not an option. The Spade employs a box section shank because they are trying to make a really stiff shank with minimal materials to save on weight, thereby lowering the center of gravity. The down side to all of this is the added complexity required to fabricate a box when compared to cutting a shape out of plate.

To make the box shank means you have to have a big giant hydraulic press and the tooling (both represent a significant capital expense) required to take a cut part and stamp it into shape (compound curvature). Mind you that's two shapes, a left and right half. Then, after you cut and install the interior web, you still have to join the two halves together.

I think the Spade is a great anchor design that suffers only from how refined it is. CG is a really hard thing to work from and this design took a lot of thought and effort to produce. Any of the various Spade spawn that are out there really are just trying to address the cost of manufacturing issue by compromising the build quality and apparently suffer in performance as a result.

One of the challenges I encounter in my daily life as a designer is that individual design components can become so refined and specific to meet their unique requirements that they become unadaptable. This can be especially challenging when they also have to integrate with other elements. It’s all about compromise.

Since the Spade doesn't really serve our purpose we can get back to your project and focus on what matters to us. You meet a guy who has probably been burning product all his life that routinely endures loads far-far in excess of our silly anchor and you hire him to make some anchors for you.

Given his experience working on heavy equipment I am guessing he would probably laugh at some of the panty-waist bickering and unsubstantiated assertions that go on in some of these anchor threads. In particular this notion that somehow bending an anchor shank renders the anchor useless.

How’s that for a Wal-Mart mentality? It’s broken, throw it away and buy another. The beloved mayor of my town has had the same pair of shoes for so long, and has had them resoled so many times, he doesn’t even know what brand they were when he bought them. The guy also happens to be a billionaire, go figure?

Has Mayor Bloomberg Really Owned Two Pairs of Work Shoes in the Past Ten Years? -- Daily Intelligencer

Pay attention here folks, be it mild steel or tool steel, once it is has exceeded its elastic limit and has been deformed, it can be annealed, normalized, and hardened to its original condition, in theory at least, infinitely!

It’s freakin metal people! That’s what metal is. It’s malleable. It’s ductile. The guy who you hired to makes your anchor leverages these qualities ALL DAY LONG. It’s not some black magic voodoo art, it’s physics.

That bent anchor who served you so well for so long deserves a little more respect that to be cast aside because you made it do something it wasn’t designed to do. Fix it, the guy in your town who on heavy equipment is the guy to do it. That same guy also happens to be capable of making a better quality product for less money.

It would be helpful to our discussion if you could clarify the costs for us by giving a breakdown of cost as materials and labor separately, and for a comparison (without naming names) a retail price you would have paid for the anchor you modeled your design on so we can see what the savings really are.

Also, I am sure everyone would love to see some photos of your beautiful anchors if you care to share. I am sure you are quite proud of them!

Meanwhile, the forecast for the weather in China doesn’t look so good.

2013 Harbin smog - Wikipedia, the free encyclopedia

[Delancey]

Originally Posted by Delancey

Pay attention here folks, be it mild steel or tool steel, once it is has exceeded its elastic limit and has been deformed, it can be annealed, normalized, and hardened to its original condition, in theory at least, infinitely!

You might be thinking "Gee Delancey, I'm not so sure about that. You call yourself some kind of designer, but you aint no engineer. What makes you think you're qualified to make a statement like that?"

To which I would respond that I was privileged in my youth to serve a brief apprenticeship with Francis Whitaker, who in his lifetime was celebrated as a national treasure.

Colorado: Tribute to National Heritage Award Recipient Francis Whitaker (Local Legacies: Celebrating Community Roots - Library of Congress)

[Delancey]

A week ago I expected I would have time this weekend to do some actual design work but it turns out to not be the case. That gives us a couple more days to consider any other sources of inspiration you can dream up.

Once we actually get started designing we will take a look at culture and it's influence on design as well as some of the work of Peter Bruce. Also we will be looking more closely at the Bügel and breaking down the roll bar concept to see how it functions.

In the meantime here is a brief review of what we have looked at so far, if I have left anything out, please let me know. Have a good weekend!


Danforth/Fortress type - Doesn't reset when broken out, aluminum version depends on extrusions which are too capital intensive for our purpose. Jonjo thinks the fact that the shank tapers on all four sides is really neat.

Bulwagga- Great design but too many component pieces made from too many different materials. Suffers from lazy fluke syndrome.

Buoyant Self-Righting/Hydrobubble- Who knows, could be a great concept. No one here could be bothered to experiment with their Mantus and report back so I guess we're skipping it.

Spade type- Great design that suffers from its own sophistication. Capital intensive due to formed parts. Simplifying construction seems to adversely affect performance.

Engine Block- We need to keep using these to burn up all the oil. Once we have accomplished that we can repurpose these as moorings.

Lead Ball With Things Sticking Out- Decidedly low-tech, no shank to bend, also functions as wrecking ball when stored on bow roller.

Convex Vs. Concave Fluke- I think we will need to look more closely at this once we've started designing.

Fabrication method- Simply put I don't think either casting or using aluminum extrusion serve our purpose. Don't confuse this with me saying I don't like these methods, I just don't think they are appropriate. This leaves either welding or mechanical fasteners such as bolts or rivets.

[Delancey]

Originally Posted by pbiJim

Speaking from experience... if you want to test the self-righting properties of an anchor, you will need to make your prototype out of the same material that use for the finished product & you will need to do the testing in water. Buoyancy & balance mean a lot here.

Would you mind sharing some of your experiences with us? I think everyone would appreciate hearing what you have to say, even if it is not specific to anchors.