Open Source Anchor Project

[Delancey]

Originally Posted by Richard_W

You lost me ... is that a question or a spec?
You want to bend the metal go for it ... just make it clear.

Yeah, I guess it's a question. Do you want to limit the potential of the anchor? Are you happy with a simple Bügel clone that doesn't have to be welded? Is that enough for you?

Or do you want the anchor to be versatile and adaptable through the ability to change flukes to suit various conditions?

If you could have a flat fluke and a concave fluke, why wouldn't you want both. If you only want a flat one, suit yourself. Don't make a concave one.

[Delancey]

Originally Posted by smaarch

following this with interest
the assumption of needing lateral stability for the shank is based on the current development of the slotted joint to work in one direction. any force in any direction other than the plane of the shank will introduce a bending force.
this makes it clear the joint between shank and fluke is a critical element, no matter the anchor design.
if this joint were designed in such a way as to rotate 360 degrees, several things become possible
1. the bending moment is eliminated
2, the configuration of the fluke is affected by the possibility of accommodating a reset in all directions.


draftsight is another open sources cad program worth a look

Can we see a sketch of what you are thinking?

[Delancey]

Originally Posted by Richard_W

You lost me ... is that a question or a spec?
You want to bend the metal go for it ... just make it clear.

My dumb, said three shanks, meant three flukes.

[smaarch]

Originally Posted by Delancey

Can we see a sketch of what you are thinking?

not near a scanner so this will conceptually have to do.
shank:
think bent bar stock? w/ threaded end to capture the fluke

fluke:
since you are bending it - a folded plate to accommodate 3? pointy ends
thinking 3....something to do w/ balance and wgt....not clear on this point.
or even 3 plates bolted together separated by 120 degrees.

[Cormorant]

For a low-tech "concave" fluke, couldn't you bolt on some angle to the sides of the fluke, creating small winglets like on the Manson Boss? It would affect the balance, so might not be feasible. On the plus side, it would help keep the side of the fluke from digging in when first setting.

Delancey, in your bending scenario above, using a door jamb, I wonder if you would bust out the door header before the steel bent. If it was a concrete and steel building, it would work fine. But a traditional stick-framed house? Not so sure. . . .

Need to get some hard data on yield strength of the various steel thicknesses that might be used, and somehow get a fix on how a door header will hold up to forces pushing upward.

[Delancey]

Originally Posted by Cormorant

For a low-tech "concave" fluke, couldn't you bolt on some angle to the sides of the fluke, creating small winglets like on the Manson Boss? It would affect the balance, so might not be feasible. On the plus side, it would help keep the side of the fluke from digging in when first setting.

Delancey, in your bending scenario above, using a door jamb, I wonder if you would bust out the door header before the steel bent. If it was a concrete and steel building, it would work fine. But a traditional stick-framed house? Not so sure. . . .

Need to get some hard data on yield strength of the various steel thicknesses that might be used, and somehow get a fix on how a door header will hold up to forces pushing upward.

Ha ha ha! Like I said, angle is everyone's bitch. We need to nail down our general fluke design before we can get to winglets but I have given it some thoughts.

One of the most basic roll bars you could make would be make a big U-bolt. Take some round bar, say half inch by however long. Cut threads on the ends then bend it into a U shape, drill two holes on the outside corners of your fluke, bolt it on. Now you have a roll bar.

This design also provides you the opportunity to put that lazy roll bar to work when he's not otherwise pulling his weight rolling you over by attaching some angle winglets. Of course you would need two more bolts to fix the angles from rotating. You know how stingy I am with the bolts....

As far as bending goes, I agree this needs to be looked at more closely, first we need our fluke data to figure out what we're bending. The point of the doorway example is that we need to be more open minded and get innovative. You know, exercise that talent for improvisation we all have. Give it a workout and make ourselves more creative in the process.

I asked for a way to bend 1/2" and all I got was "you can't do that" to which I say really? Are you sure about that? I bet there's nothing we can't do if we put our minds to it.

The car jack was one example. How about using the weight of the car itself? Why not give that car sitting in your driveway another purpose in its life besides driving you to the mall to buy a bunch of crap made in China?

Lazy car, get too work! Make me an anchor!

[noelex 77]

I would make the prototype as adjustable as possible. For the final design I am not sure it is a great advantage, especially if it adds complication. The only commercial anchor with any adjustability is the Fortress (with two fluke angles) and it's not unusual to see people trying to use it on the wrong setting for the conditions.

One idea that is worth incorporating in the prototype is the Raya's different fluke attachment points (see the two holes in the photo) it is an idea that has not been copied by any other manufacturer so maybe there were some practical problems, or maybe it just did not sell. For the prototype multiple attachment points would speed up development.

It is going to be enough work to develop one design of anchor. Concave and convex anchors work differently and I would concentrate on one. I think the evidence strongly supports concave as the superior option.

[foolishsailor]

Since we are looking for a new design - Is it mad to ask why even have a shank? Why not attach directly to the fluke with chain?

The principal would be the same as attaching string to a kite, the chain would split in two very close to the anchow (via a shackel) so that two chains with a specific geomtry that encouraged the anchor to dig in, just like childs kite is angled to the wind.

To ensure the anchor oriented itself you would need it to be convex and with a roll bar. All of which could be bolt on - including the two anchor attachment points.

[Delancey]

Originally Posted by noelex 77

I would make the prototype as adjustable as possible. For the final design I am not sure it is a great advantage, especially if it adds complication. The only commercial anchor with any adjustability is the Fortress (with two fluke angles) and it's not unusual to see people trying to use it on the wrong setting for the conditions.

One idea that is worth incorporating in the prototype is the Raya's different fluke attachment points (see the two holes in the photo) it is an idea that has not been copied by any other manufacturer so maybe there were some practical problems, or maybe it just did not sell. For the prototype multiple attachment points would speed up development.

It is going to be enough work to develop one design of anchor. Concave and convex anchors work differently and I would concentrate on one. I think the evidence strongly supports concave as the superior option.

I've given the concept of allowing for adjustable geometry in the fluke shank angle some thought. They do it the oil rig anchors, but as to you say it makes things more complicated which is bad.

I also don't think it makes much sense for a cruising sailor who doesn't pack the equipment necessary to drill core samples and determine what the bottom soil conditions are in any given anchorage.

That said, I think having different flukes for generic extremes that share the same shank/fluke connection makes sense. For hard rocky soils, you want a sharp pointy fluke with limited edge profile. For mud you want a big wide flat fluke with maximum area. For sand and everything in between you want a scoop shape.

These are all within our reach.

One thing to keep in mind is that soil conditions and how they relate to fluke angle has been pretty thoroughly investigated by people with a lot of money tied up in the oil business. I think like 32 degrees is optimal for penetrating rocky soil, 50 degrees for mud.

Just about any anchor on the market is closer to 32 than 50 because fluke angle as it relates to extremes in soil conditions is not a two-way street. 32 will penetrate into mud, 50 will not penetrate in rock. Basically, unless you only ever anchor in rock, your one-size fits all fluke angle is not living up to its full potential.

You can read about all this stuff in the Vryhof Anchor Manual downloadable as a .pdf here, compliments of Jonjo.

http://www.vryhof.com/company/news.php

[noelex 77]

Originally Posted by foolishsailor

Since we are looking for a new design - Is it mad to ask why even have a shank?

XYZ anchor owners are sending up a cheer just for you.

Although they did keep a mini shank so we are not quite there. I also think they beat us to the bottle opener idea (see on top of the shank)

[Delancey]

Originally Posted by noelex 77

I would make the prototype as adjustable as possible. For the final design I am not sure it is a great advantage, especially if it adds complication. The only commercial anchor with any adjustability is the Fortress (with two fluke angles) and it's not unusual to see people trying to use it on the wrong setting for the conditions.

One idea that is worth incorporating in the prototype is the Raya's different fluke attachment points (see the two holes in the photo) it is an idea that has not been copied by any other manufacturer so maybe there were some practical problems, or maybe it just did not sell. For the prototype multiple attachment points would speed up development.

It is going to be enough work to develop one design of anchor. Concave and convex anchors work differently and I would concentrate on one. I think the evidence strongly supports concave as the superior option.

Different attachment points on the shank is interesting idea, have to look at that more closely.

[monstads]

Originally Posted by Delancey

The car jack was one example. How about using the weight of the car itself? Why not give that car sitting in your driveway another purpose in its life besides driving you to the mall to buy a bunch of crap made in China?

Lazy boat, hanging there in your comfortable sling.. Hey, mister travel lift operator, how about a "touch-n-go" on that piece of metal over there? Buy ya a beer!

Beyond the tongue in cheek, there actually would be some "natural engineering" at play here as well. . If the boat weight easily crushes your metal fluke, it's too thin. If it doesn't bend, it's thicker than needed, so go down one size until it does.. After all, if the entire displacement of your boat can barely bend the metal, it should hold :-) Yes, I know this is a point load, depends on fluke area, contact area, etc, etc. Just going back to the hypothetical remote Island "figure sonething out" scenario (although one could argue that if your boat is in the lift, you probably don't need that anchor as badly. ..)

[foolishsailor]

Originally Posted by noelex 77

XYZ anchor owners are sending up a cheer cheer just for you. Although they did keep a mini shank so we are not quite there. I also think they beat us to the bottle opener idea (see on top of the shank)

+1 on the bottle opener. Guess you can haul up the anchor and drink beer if you drag onto the beach? I saw in the chart you posted that XYZ didnt fare so well. Also see a flat fluke.

When I have a chance Ill draft up a simple drawing in Autocad Inventor what I am thinking of.

Dont want to derail the current discussion, but I am curious if any manufacturer or CFer has experimented with shankless anchors?

Seems it would radically simplify the design and cost if a shank could be removed and one was still left with a quality anchor?

[foolishsailor]

Should we setup up a shared file repository?

I can immediately setup a shared google drive where we can deposit CAD and variant files for others to modify. Access can be setup tied to email addresses.

Is anyone interested in this?

I for one would love it - especially if we encouraged the proper format for saving files; ie CAD, DWG, Solidworks, Inventor, etc...

Delancey,

As this is your idea, I can setup a google drive right now and give you admin rights?

[Delancey]

Originally Posted by foolishsailor

Since we are looking for a new design - Is it mad to ask why even have a shank? Why not attach directly to the fluke with chain?

The principal would be the same as attaching string to a kite, the chain would split in two very close to the anchow (via a shackel) so that two chains with a specific geomtry that encouraged the anchor to dig in, just like childs kite is angled to the wind.

To ensure the anchor oriented itself you would need it to be convex and with a roll bar. All of which could be bolt on - including the two anchor attachment points.

I looked at this early on, some of the oil rigs anchors use bridle attachments so it's not a new design. My version was cut from a piece of pipe. I couldn't figure out why no one was using it for a small boat anchor so I figured there was something wrong with it that I was missing and moved on to other designs.

Maybe worth a second look.

One thing I like about this fluke design is that the pattern for it is so super simple. You draw out a triangle on a piece of paper and tape the paper to the pipe and make your cut. Any one with a tape measure can make a triangle whatever the angles. Everyone has some paper lying around being lazy, make me an anchor you scrap of paper!