Open Source Anchor Project

[Delancey]

Here you can see the birds beak digging in, also note the winglet at the back helping to turn it. I put a bar up front, can't push on a rope. Not sure how I feel about it.

[Cotemar]

Maybe time to make one and give it a go.

[roland stockham]

New thought

The drum idea is looking a bit complex, I had a simpler thought

Pipe anchor;
Take a length of heavy steel pipe
Cut a length about twice it's diameter
Cut diagonally from a 2/3 of its length to end to give required angle of attack and form a shovel.
Drill 1 hole at the top front
Attach shackle and chain to front hole. If you lift it by the chain it should tip down at the front, If not cut some more off the back of the pipe till it does.
Drill hole at the back.
The back hole is so that you can shackle a number of pipe anchors together to form something similar to a series drogue increasing wt and holding. This means you could use quite small pipe.
Might be worth trying 2 holes and a chain bridal if it needs to be more stable when digging in

Sorry no pretty drawings!

[Cotemar]

roland stockham,

Anything is game here, so a scanned hand drawing is ok with us.
Draw it up and show us the real deal.

[Delancey]

Originally Posted by roland stockham

New thought

The drum idea is looking a bit complex, I had a simpler thought

Pipe anchor;
Take a length of heavy steel pipe
Cut a length about twice it's diameter
Cut diagonally from a 2/3 of its length to end to give required angle of attack and form a shovel.
Drill 1 hole at the top front
Attach shackle and chain to front hole. If you lift it by the chain it should tip down at the front, If not cut some more off the back of the pipe till it does.
Drill hole at the back.
The back hole is so that you can shackle a number of pipe anchors together to form something similar to a series drogue increasing wt and holding. This means you could use quite small pipe.
Might be worth trying 2 holes and a chain bridal if it needs to be more stable when digging in

Sorry no pretty drawings!

Maybe you could cut up a coffee can or plastic cup with tin snips or scissors. Rig it with some string, show us some pics? I always mock stuff up whenever I can.

You could maybe even make it out of cardboard and tape. What you're going after is the geometry so weight doesn't really matter to test your concept.

[Delancey]

Originally Posted by Delancey

Here you can see the birds beak digging in, also note the winglet at the back helping to turn it. I put a bar up front, can't push on a rope. Not sure how I feel about it.

Needs work, maybe rethink the tip of the fluke a bit. Ditch the chain, round bar is cheaper and lighter, our guy on the beach can forge an eye and seize it with wire. Maybe add a fourth leg to that middle formed rib.

It does have bomber connections, I nestled the bent round bar ribs right in behind the formed rib on the outside of the fluke. Slots with round ends to allow the chain(bar with formed eyes) to pass through the front and then has the bent rod rib threaded though the last link on the backside. All of it should be super strong.

If was tricky to make everything work, as far as working with the proportions of the drum like with the rib locations, but still the load should be pulling from the center of resistance of the fluke. Would be nice to have it pulling from a point further forward of the tip but dems da breaks.

Interesting to think about the tripod thing though, as far as bent shanks goes.

[Cotemar]

With a 23 inch diameter. The barrel anchor is going to be a big one.

Would be good to mock one up and take it to a boat and see how it rolls over and onto a bow anchor roller.

[Delancey]

Originally Posted by Cotemar

With a 23 inch diameter. The barrel anchor is going to be a big one.

Would be good to mock one up and take it to a boat and see how it rolls over and onto a bow anchor roller.

Might fall into the storm survival anchor category. Then again a quick search reveals bubbasbarrels.com has used stainless barrels for $200 which is awful cheap for a giant stainless anchor.

Looks like there are 30 and 20 gallon sizes at about 18" and 16" in diameter which is good, will have to look at those tomorrow size wise.

55 Gallon Stainless Steel Barrel - Open Head | Bubba's Barrels

Open Head Stainless Steel Drums- Type 304 SS | Freund Container & Supply

[Delancey]

Too bad we can't get any dimensions for materials thickness for other anchors. We could be working on the flat plate anchor right now instead of this oil drum nonsense.

Just exactly why is it we can't get any dimensions? I even started a separate thread just for the purpose. Panope was nice enough to get us dims on a Manson Supreme. What about everybody else? We need as many brands as possible.

I mean, at my marina it's all Deltas or CQR's so no luck there. For all the bitching about different brands of anchors on this forum you'd think people actually had these anchors and could do us a flavor and bust out with a tape measure, what's that take five minutes?

Oh well, I guess I will just work with my oil drums for the time being. Too bad though, as much as I like the drum concept I think the plate anchor is the one people actually want.

[Cotemar]

A Delta 20kg-44lbs anchor has a
.629 inch thick shank
.236 inch thick fluke at the back end.
The tip is just a big casting for tip weight.

[foolishsailor]

Hey All,

I have setup a the Open Source Anchor Project using the OpenDesign Engine at

https://opendesignengine.net/

The project is found here: https://opendesignengine.net/projects/osap/

If you register at the site (free) you can then PM me your OpenDedsign username (PM me here at CF) and i can add you to the project. As this was born at CF I have disabled the forum over there so that we continue to discuss the development of the project here.

The DesignEngine is used to track:

1. Links and Data
2. All images
3. Development and design process
4. Version Control

Have a look over there, specifically in the following sections information has been added: Overview, Wiki, Issues, DMSF (Core module it is used for version control), Documents, and Files.

The project is setup just like Wikipedia - anyone can add, modify or edit the content who is a member of the group. All changes are immediate but the history of the documents and sections are maintained so that evolution can be monitored and kept in a group agreed direction.

What I would like to see is an agreed upon base file type for sharing that is useable on all CAD programmes. For example I use Inventor, others use SolidWorks and others SketchUp. All these programmes can export and import file types. I would like to see the CAD files of different designs to be uploaded as well as .jpg or .png uploaded.

If you have any questions ask - perhaps it would be best to start a separate thread on how to work collaboratively in an open hardware design environment?

Most important, and as a Mod who represent CF I have to say this - I do not wish to drive traffic away from CF and would like to ensure that all images and discussions happen on this forum and the OpenDesign site be used as a repository for documents, documentation, and as a project management tool only.

[foolishsailor]

Also,

Have setup a CF Social Group you can join here:

Cruisers & Sailing Forums - OSAP - Open Source Anchor Project

[Bestathook]

What about a plain section of a steel cylinder, with a bar across the bottom to attach a stock.

If the length of the cylinder is cut such that the angle of the stock, from the center of one end of the cylinder, to wherever it touches the rim of the other end, is the desired angle of stock to maximize penetration, the anchor will always be in setting position. A bulawaga has a similar arrangement to set angle.

It would be possible to cut a few big teeth, or whatever pattern minimizes penetration.

OK what do you think of this arrangement?

[Delancey]

I guess a more positive angle of attach is just a perk to the birds beak. What it really does is give a rotational moment when one side digs in first. Look at the offset between the shank and the tip. Imagine pushing against one tip while you pull on the shank, see how it wants to turn and bring the other tip down.

[Delancey]

Here's a photo of the Bruce Dennla Anchor. Of course there is nothing new about salient geometry, there also isn't much new about using an offset fluke point to achieve a turning moment to assist in orienting the anchor to align with the load.

Think about a Navy Stockless-type or even a Danforth-type. Both of which are arguably a single bifurcated fluke even though they appear to have two flukes. Really it's just one fluke split in two.

The Bulwagga comes to mind as another example of an anchor that uses this principle, but does so with distinctly separate but connected flukes.

Peter Bruce took this principle one step further with the three points of original Bruce Anchor design. That's what's really going on with the the two palms on the outside.

They are meant to catch the bottom and cause resistance, which in turn creates a pivot point for the anchor to rotate about, so the central palm is optimally positioned to dig in. You can see this pretty clearly when you look at his original patent drawings.

I have some theories about why the Bügel anchor design overlooks this feature which I will discuss as promised in a future post about culture and it's influence on design.

In they meantime we are left to wonder why all the post-Bügel copycats have overlooked this detail as well. It could be that because they were copying instead of really innovating that they didn't understand how this feature worked. Maybe as of this writing we will see a new spate of "innovative" anchors designs employing this concept.

I am not saying they don't understand the need to have the anchor steer itself into position, just saying the way they do it doesn't seem optimal to me. They do this by the addition of the winglets at the rear outside corners of the fluke, near the roll bar attachment.

The thing is, the winglets only work on the drag they create. Which, when it comes at the back, has minimal influence in terms of steerage, the winglets have no real force to leverage and are really sort of only reactive. I think it is much more effective to steer from the front like a canard.

Of course this single point thing could just by a one-size fits all situation. I can think of rock for example as being less than ideal soil for the bifurcated fluke.

It's nice for us with the OSA to not be so constrained. With our interchangeable flukes we can have a heavy single-point spike for rock, and bifurcated flukes for the sand and mud where it matters the most. Sweet!