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Old 10-11-2014, 04:16 AM   #781
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Markpierce

If you want to trust your vessel to a mushroom anchor, be my guest. Why not just use a kellet (or an old car battery).

I had always imagined that mushroom anchors work (like my concrete block) by their resistance to movement (friction) and their ability to settle over a period of time.

So, yes, gravity is important if you have time, most of us move on (in terms of our anchor location) before time has much influence.

If you believe in gravity, for an anchor - then you will miss the benefits of the alloy Excel or alloy Spade, your loss.

If gravity was a factor, the oil rig anchors would be filled with lead, or uranium (for oil rigs anchors cost is not an issue). If gravity were important then anchors would be made from a thin film of steel and a lot of lead. If gravity were an issue then the Fortress would be as well engineered as it is and made from HT steel (with lead somewhere).

it is not about weight, but design and surface area.

If we could use Kryptonite then anchors would be made from paper thin Kt.

And carbon fibre, reinforced polymers lack abrasion resistance (been there, done that).

Jonathan
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Old 10-11-2014, 12:12 PM   #782
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Carbon Fiber Anchor

"And carbon fibre, reinforced polymers lack abrasion resistance (been there, done that)."

Sorry, it was a joke. I guess I should have put a one of these in there
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Old 10-11-2014, 12:57 PM   #783
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Quote:
Originally Posted by Djbangi View Post
Markpierc]

it is not about weight, but design and surface area.

Jonathan
The anchor tables I look at, including Fortress, show a heavier anchor of the same design exhibits greater holding power than a lighter anchor of the same design.That is precisely why I purchased an FX55 rather than the FX35. Others note the same on this thread.

Had the Fortress test been done in Blue Mouse Cove in Glacier Bay the results would be vastly different. Fortress picked an East Coast venue where many boat and anchor and suits their game plan to a T. Do the test on a hard pan, rocky or glacial till bottom and the results would be very interesting.

Sir Isaac dropped enough apples to convince me that mass is relevant Seems he convinced Delfin too.

Mark, my lunch hook for years on a smaller vessel was a mushroom. Easy to wash and store and dug into the Mississippi River bottom like you wouldn't believe. Our primary for those washed bottom sands was a Danforth. One size up of course
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Old 10-11-2014, 03:39 PM   #784
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Regarding steels and weight;

My second XYZ as shipped new is in pic #1. The fwd end of the fluke was high grade SS .. (1700 alloy I think) and due to a trade I wound up w a back fluke and shank but no tip. I had one made to my specs in Craig AK but was limited to mild steel. As I recall I used a scrap piece laying around .. 5/16" like the fluke. I was planing to make a new fluke tip out of 4140 steel w a slightly different shape. But now this thread has motivated me to use mild steel for the new tip but 3/8" thick. I'll have a little more tip weight and a narrower tip end (new mod) so the anchor may have more universal performance. It has set 10 or 12 times along the BC coast and held fast even in a 55 knot gale w the wide fluke tip in the pics. The mild steel tip suffered no damage. It can be seen in the last pic that the fluke tip has a great angle and very aggressive attitude for penetrating the bottom when laying on it's side. The mod will probably boost the weight up to 20lbs (from 18) .. still a very handy size and weight.

I'm convinced this anchor has a lot of promise but only more time and experience will tell.
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Old 10-11-2014, 05:31 PM   #785
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The anchor tables I look at, including Fortress, show a heavier anchor of the same design exhibits greater holding power than a lighter anchor of the same design.That is precisely why I purchased an FX55 rather than the FX35. Others note the same on this thread.

Had the Fortress test been done in Blue Mouse Cove in Glacier Bay the results would be vastly different. Fortress picked an East Coast venue where many boat and anchor and suits their game plan to a T. Do the test on a hard pan, rocky or glacial till bottom and the results would be very interesting.

Sir Isaac dropped enough apples to convince me that mass is relevant Seems he convinced Delfin too.

Mark, my lunch hook for years on a smaller vessel was a mushroom. Easy to wash and store and dug into the Mississippi River bottom like you wouldn't believe. Our primary for those washed bottom sands was a Danforth. One size up of course
You can measure the size of an anchor a number of ways, mass, or weight, is the most common. An alternative is surface area, which is one measure both Spade and Rocna use (I wonder why bother). As mass increases, so does surface area. So you might want to believe that its the increase in the mass (and Sir Isaac) that allow your anchor to perform but you then need to square that belief with the reality that a steel and alloy anchor of the same size and design both have exactly the same maximum holding capacity. Explanations?

Holding capacity is directly proportional to an increase in size, whether you measure size by weight or surface area. But if weight were the issue then if you double weight you would double holding capacity, unfortunately this does not apply. Much work has been done, Fortress, Vryhof, Knox and in reality the increase in capacity is less then the increase in weight, so double weight and you have less than an increase in holding capacity - obviously and perversely defying Sir Isaac.

Sad but true.

The big issue of surface area is - what do you measure. If its a Bruce and you flatten out the fluke you have a large surface area, a Fortress is more obvious. So what do you measure - what is the effective surface area.



Eric,

I'm fascinated by your experiments with the XYZ. To me it has the idea, its like the Raya, but with a flat fluke. The Raya had good reports (and copies are sold out of NZ, though I've never seen one). The flat fluke obviously works, Bugel, Fortress.

Stick at it.

The other idea might be to make the toe from HT steel.

Jonathan
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Old 10-11-2014, 05:48 PM   #786
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Jonathan,
I decided to forgo the HT steel in favor of a thicker mild steel toe. Could even make several at a time as mild steel is so cheap. The existing mild steel has worked for a time so a bit thicker toe should need attention rarely if ever.

The chisel edge on the end w HT steel should last much longer than the mild steel but I don't have enough time using it to know if the mild steel will be hard enough. One could grind a new edge on the tip several times as well. My tip is longer than the original so area balance should't be an issue. The increased area fwd seemed to cause no problems.

As w many other anchors setting in an upright position at shorter scope is probably the order of the day. I think anchors of this type need to perform well setting either upright or on their sides and I think several don't do well one way and fine the other.
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Old 10-11-2014, 06:14 PM   #787
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Eric,

I have found that the issue with HT steel is not the cost, but simply finding a stockist that will supply small volumes, offcuts. They cut so efficiently getting an off cut of any size is difficult. Often the offcuts are then the wrong thickness. As you mention, mild steel is so readily available. Maybe when you are happy with what you are doing you can then use HT.

An anchor might be better set on a long or short scope - but at the end of the day its needs to re-set itself what ever the scope as they will always at some time or other pull out (usually when you are asleep!).

Not mentioned but the Fortress tests, at a long scope, were indicative of an anchors ability to set (at a long scope) and this is seldom investigated (and was an accidental result from the testing). Most testing is at 5:1 but many anchors are used at much longer scopes - and its what happens at longer scopes that is of interest.

Good luck with the modifications.


Is XYZ still active, I have not checked for a long, long time?

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Old 10-11-2014, 06:29 PM   #788
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Regarding steels and weight;

My second XYZ as shipped new is in pic #1. The fwd end of the fluke was high grade SS .. (1700 alloy I think) and due to a trade I wound up w a back fluke and shank but no tip. I had one made to my specs in Craig AK but was limited to mild steel. As I recall I used a scrap piece laying around .. 5/16" like the fluke. I was planing to make a new fluke tip out of 4140 steel w a slightly different shape. But now this thread has motivated me to use mild steel for the new tip but 3/8" thick. I'll have a little more tip weight and a narrower tip end (new mod) so the anchor may have more universal performance. It has set 10 or 12 times along the BC coast and held fast even in a 55 knot gale w the wide fluke tip in the pics. The mild steel tip suffered no damage. It can be seen in the last pic that the fluke tip has a great angle and very aggressive attitude for penetrating the bottom when laying on it's side. The mod will probably boost the weight up to 20lbs (from 18) .. still a very handy size and weight.

I'm convinced this anchor has a lot of promise but only more time and experience will tell.
Eric, what does the bottle opener thingie do?
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Old 10-11-2014, 07:56 PM   #789
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Carl said;
"Eric, what does the bottle opener thingie do?"

Basically the same thing as the roll bar.

Jonathan,
His (Draggo) web site is still there ...

xyzanchor.com
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Old 10-11-2014, 08:26 PM   #790
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Carl said;
"Eric, what does the bottle opener thingie do?"

Basically the same thing as the roll bar.

Jonathan,
His (Draggo) web site is still there ...

xyzanchor.com
I don't get it. Why the hole in it? If it works like a roll bar it is probably superior since it would present very little resistance to burying, but I still can't quote grok what the designer had on his mind. Perhaps peyote?
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Old 10-11-2014, 09:03 PM   #791
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Carl,
Like the roll bar when you jam stuff through a hole or between things it increases the drag or resistance. The "mast" is there for when the anchor winds up upside down it digs into the seabed a little bit keeping the trailing edge of the anchor up and that tends to keep the nose or toe of the fluke down. Also I believe it's tended to "steer the fluke" a bit so it would align more closely to the direction of fluke travel over the bottom. The more a sideways setting fluke gets the more it tends to plow sideways and fail to penetrate the bottom. The fluke going straight on into the bottom is obviously the most advantageous fluke tip attitude.

Yes I think it's superior to the RB as it offers no drag at all until the fluke is buried 5" or so. Then the draggy part of the mast is higher yet and the weight and size of the mast is far smaller than any RB I've seen.
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Old 10-23-2014, 07:55 PM   #792
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Gents,

FYI - A link to PassageMaker's story about the testing.

https://www.dropbox.com/s/lcypucilvz...EAMAN.pdf?dl=0

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Old 11-07-2014, 08:01 AM   #793
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I just learned yesterday (from an anchor thread on the other forum) that Spade anchors can be dismantled... a factoid I'd never noticed before.

Anyway, that of course led to visual comparison between the Spade and some other shapes... especially the Sarca Excel and Lewmar's Delta.

Hmmm... looks to me like the upward bending "flaps" at the trailing end of the Excel and Delta fluke would cause the aft end to sink and the toe to rise, once these anchors have dug in far enough so those "flaps" might begin to have some effect.

Which would mean no additional burying, even with more pull.

Which suggests to me that downward bending "flaps" (instead) would cause the toe to continue digging deeper, so the anchors could bury themselves even further.

????

How the heck would one better identify those "flaps," anyway?

And then it seems the aft corners of the Spade would do the same thing; once submerged in substrate, addition pull might cause the aft end to depress and the leading toe to rise...

???

I don't see anything in the Danforth design (or Fortress implementation) that would make the toe(s) rise, given additional pull...

This from an obviously non-anchor-engineer sorta guy... in the midst of donning fire-retardant suit...

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Old 11-07-2014, 08:43 AM   #794
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Chris, having anchored with a Delta hundreds of times in all different bottoms, I can tell you that is not the case, I surmise from the angle of the shank. I have raised the anchor from sticky mud with the ears and entire shank covered in mud, and it really took some doing to break the anchor out, redeploying the snubber, jockeying the boat, and just waiting for the thing to break out with the bobbing motion of the boat. I can recall the anchor coming up backwards a few times, where it seemed obvious that the boat had merely clocked around with the tide and the current was not strong enough to break the anchor out even in"reverse", aided by the drag of the chain in the mud.

As for the latter, I can recall another time we were anchored in sand in very clear water. I was walking the side decks first thing one morning a noticed what looked like an anchor just off the port side, about 2/3 of the length of the boat aft. Then noticed a chain emerging from the sand here and there in a straight line forward, and quickly came to the realization it was OUR anchor... we were merely lying to the buried chain!
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Old 11-07-2014, 10:26 AM   #795
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Ranger,
You're right. The trailing edge turned up like the elevator on an airplane does cause the anchor to "try" to pitch up and it does (to some extent) preventing the anchor from burying further than it does. But the overpowering force involved with the anchor is the fluke itself and the relationship of the pull from the rode and the anchor taken as a whole.

If the angle of the rode gets high enough on a typically buried anchor then the shank pitches the fluke up and out it comes. But if the rode is lying flat on the bottom the angle of pull on the shank dosn't pitch the anchor up. But when the anchor buries a ways the angle of pull on the shank is much more upwards as the chain instead of being concave in the water (catenary) the chain becomes convex (reverse catenary) so the chain in the water aids the anchor's performance in the water and the chain (or line) reduces anchor performance in the sea bottom ... such that eact anchor and rode combination has a point in a fluid sea bottom where the forces neutralize and the anchor dosn't burry deeper nor does it rise up.

But little things like up turned trailing edge flukes and high roll bars (high relative to the rest of the anchor) and up turned TE of flukes causes the anchor to "level off" and cruise through the sea bottom at an "inverted altitude" less than others so those anchors don't penetrate as deeply as others. That dosn't mean they don't penetrate the bottom to a depth whereas you can't see the anchor in a highly receptive bottom but it does mean that they will not penetrate as deeply as an anchor that does not have such appendages .. roll bars and up turned flukes.

So Chris you're right but the upwards force acts in concert w many other forces so that the anchor actually works even though it's trying to some extent to pitch up. The trailing edge upturn on the Rocna is probably one of the reasons the Rocna dosn't do as well at shorter scopes but w the rode more horizontal the upturned TE of the fluke increases holding power. The Manson Supreme does not have the trailing edge upturn and has slightly less holding power at long scope but performers much better at short scopes. At least that has come to pass on several anchor tests.
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Old 11-07-2014, 11:14 AM   #796
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Hmmm, George says no and Eric says yes. I must be about right!

Semi-seriously, I've used a Delta, too, and results are similar to what George describes (except for the times it didn't work, and those were at least well explained).

OTOH, I'd still suspect even deeper would be even better. If the design makes these anchors penetrate below the surface... but then they level off so any additional pull (as parallel to the bottom as possible, given rode, catenary, etc.) means the anchor simply stays only at that penetration level... I'd wonder if even better holding could be achieved through even deeper penetration.

If the up-turned trailing edges are prohibiting further penetration... maybe down-turned edges instead would cause that...

It doesn't seem to me that down-turned trailing edges -- instead of up-turned -- would make any significant difference in manufacturing costs...

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Old 11-07-2014, 11:25 AM   #797
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Good morning Chris,
Look at my anchor in post #784 and see down turned trailing edges. Also the shank w it's self righting "horn" offers very little resistance to fwd travel, or pitching up until it's about 10" buried and then the forces of evil are probably smaller than any other anchor.
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Old 11-07-2014, 11:32 AM   #798
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Good morning Chris,
Look at my anchor in post #784 and see down turned trailing edges. Also the shank w it's self righting "horn" offers very little resistance to fwd travel, or pitching up until it's about 10" buried and then the forces of evil are probably smaller than any other anchor.

Yeah, like that!

I do remember seeing that, and thought at the time that the shank seems connected too far forward. Because it's difficult to develop truly parallel pull (to the bottom), I thought upward pull would keep the toe from digging in very much before being ripped out of the substrate...

Those were just my impressions, though; obviously I'd defer to actual empirical factoids

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Old 11-07-2014, 01:53 PM   #799
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Yeah, like that!

I do remember seeing that, and thought at the time that the shank seems connected too far forward. Because it's difficult to develop truly parallel pull (to the bottom), I thought upward pull would keep the toe from digging in very much before being ripped out of the substrate...

Those were just my impressions, though; obviously I'd defer to actual empirical factoids

-Chris
Not sure the edges matter. An anchor that holds really well is the Sarca Excel, which has upturned edges. Another is the Ultra, which has down turned edges. Another that does well is the Manson Supreme that has no edges. Whatever impact the edges have, they are part of a broader design and weight distribution matrix that seems to overwhelm the edge configuration.

Might be over thinking this one....
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Old 11-07-2014, 02:35 PM   #800
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Not sure the edges matter. An anchor that holds really well is the Sarca Excel, which has upturned edges. Another is the Ultra, which has down turned edges. Another that does well is the Manson Supreme that has no edges. Whatever impact the edges have, they are part of a broader design and weight distribution matrix that seems to overwhelm the edge configuration.

Might be over thinking this one....

I'm often accused of that.

And it's easy to agree that several anchors do very well already.

I hadn't looked closely at an Ultra before. I see their website says specifically that the "side wing plates actually help the anchor bury deeper when pulled laterally..." which is sorta what I was positing. Didn't do all that great in the Fortress tests, although I'm not sure I can very well interpret the way design might have affected that graph. And then there's the mud factor.

Edit: I just viewed the demo video of the Ultra anchor being set in 18' of water. I'm not overwhelmed. The fluke area buried, but the whole anchor did not. I'm thinking a better goal is the whole anchor underneath the substrate, shank and shackle, some of the rode, the whole nine yards... and with it all still diving if under further lateral pull -- until reaching horsepower limits

The Manson Supreme trailing edges (or not) look slightly like the Spade aft end. Yes, they're not turned up separately from the fluke area, but I'd say they're geometry -- within the concave framework -- and would guess they would do the same as upturned trailing edges, albeit perhaps less noticeably. Didn't seem to do all that great in the Fortress tests, although that's likely not representative in something other than soft mud.

While the Sarca Excel wasn't included in the tests, the Delta design looks similar (to me, sorta kinda)... and the Delta didn't do all that well. Maybe the Excel would have done better (probably that "broader design and weight distribution matrix" stuff; I'm reasonably sure Rex could speculate). In any case, I began this by wondering how the Delta would have fared with down-turning aft edges ("wing plates"?)... and then wondering if a similarly-modified Excel would have done even better.

I guess I'm thinking about how anchors could be made to "dive" more if the trailing edges were to promote that behavior better.

Over-thinking, probably

-Chris
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