Anchor choices

[Mike OReilly]

Originally Posted by Dockhead

Steve has done such a great service to the community

Between him and Noelex, I think we have 1000x more concrete knowledge about anchor behavior than we did a few years ago

This video is sure on topic -- he says that all of the small anchors he tested work less well than you would expect.

That corresponds to my experience.

Agree 1000% . I wish there was some sort of award we could give to these two. I'm just loving the videos.

I have no practical experience with the smaller anchor syndrome, but I really think it's worth exploring in real-world testing. The theory that there is some sort of minimal threshold for effective anchor function appears to be supported by good evidence.

[Adelie]

Originally Posted by Mike OReilly

Agree 1000% . I wish there was some sort of award we could give to these two. I'm just loving the videos.
.....

Mash the “Thanks” buttons maybe?

[Panope]

Originally Posted by Dockhead

Steve has done such a great service to the community


Between him and Noelex, I think we have 1000x more concrete knowledge about anchor behavior than we did a few years ago


This video is sure on topic -- he says that all of the small anchors he tested work less well than you would expect.


That corresponds to my experience.

Thanks for the kind words, Dock.

.
I am just now editing a new anchor test video depicting another "small" anchor (17 lbs.). I'll not divulge which brand, but I will say that the design performs very nearly as well as its larger version (a 47 pounder).


Video should be ready to post in a day or two. Stay tuned......

Steve

[evm1024]

Not to be too worried about comparing apples to oranges - size effects are based in materials strengths, density and so on.

The ability to break through a layer of hardpack, weeds and the like is directly related to the contact force (psi) and other factors.

No way would a 35# anchor "interact" with the substrate the same way a 100# anchor would.

Here is a simple thought - Take a and and drop it 100 time its body length. Not much happens.

Take a human and drop them 100 times their body length and ...

[carstenb]

We are a 40 foot boat, fully loaded for cruising and weigh in at about 12-13 tons. We have a 30kg Mantus and 8mm chain. We have been on the hook close to 1000 nights now in the past 4 years. We have anchored in most kinds of bottoms and our Mantus has only dragged once (ON Fatu Hiva where everyone drags - the bottom is a sloping rock ledge with a thin layer of sand on top) I mailed quite a bit with both Peter Smith (Rocna) and GReg Knutsen (Mantus) before buying an anchor. Both said that if the anchor was going to be the primary storm anchor - go up one size from the website recommendations.

To my mind there are three basic factors to an anchors holding power

1- weight - heavier digs in deeper and heavier is more difficult to move

2- shape of the "plow" or the concave plow. It shaped correctly it will hold more substrate and thereby give you better holding

3- Size of the plow - the larger the surface area of the plow the greater the holding

yes the sharpness of the tip is also important

Dashew's comment about the anchor is getting close to the right size when everyone laughs at it is spot on.

We sleep soundly at night because we trust in our anchor - but also us an anchor alarm. We have been on the hook in sustained 40 knots winds and 2-3 meter high swells (this is not recommended) but we slept soundly..........

[Izikalvo]

Just to be clear, I am not talking about setting or resetting, what interests me is, assuming that you have the best anchor in the world that sets and hold and even makes coffee, on the holding issue, would you still prefer a heavier anchor?

BTW for all of you Mantus fans we have uploaded a page showing the technical differences of the two anchor designs.

Also, Steve's boat is napping, at the moment she will be in the water we will be more than happy to send him one of our smaller size anchors for testing.

I hope I didn't get in trouble with the admin here, anyway, would you trust heavier anchor to hold better? leave the rest aside, just for holding, when you know for a fact that if the anchor is not set well because of its size and might have some parts sticking out of the seabed, something that might interfere with the chain and you might get into trouble because of it?

[rslifkin]

If the light anchor is shown to work well, I'd have no problem using it. And I'd probably take advantage of that light weight to carry an even bigger one, assuming I could make it fit.

That's why the Fortress sells so well. It's not good at everything, which is why they're not all that commonly seen on the bow. But for the things it's good at, it's really good, and it's lightweight and easy to handle. If someone could make an anchor with the straight line holding power vs weight of a Fortress that would set easily in pretty much any bottom and handled veering loads well, I think they'd sell a lot of anchors.

[kmacdonald]

Originally Posted by noelex 77

So an anchor dragging with a wind shift is often an indication that the anchor had only marginal grip in a straight line pull and therefore broke out while rotating. A larger anchor will definitely help in this situation, as will an anchor that “shuffles” better and retains a higher percentage of its straight line holding power.

No!!!! My anchors have held flawlessly in 50+ knot winds. They are not oversized but not undersized either. They are not "marginal" by any stretch of the imagination.

[kmacdonald]

Originally Posted by Panope

Most recently I have become interested with the effects of anchor SCALE (does a smaller version of an anchor behave the same has larger?). This research is just getting started, but it appears that scale factor might be significant enough that we should not even make generalizations about a particular anchor BRAND (Bruce anchors do_____) without stating the size also.

Steve

I've talked about that here several times. I've always suspected that anchors don't scale linearly with weight and that there may be an "optimum" size of each brand of anchor. I look forward to seeing your test results. Thanks.

[noelex 77]

Originally Posted by kmacdonald

No!!!! My anchors have held flawlessly in 50+ knot winds.

Sorry if I misunderstood.

This post led me to understand you had experienced some problems:

Originally Posted by kmacdonald

The problem I've had is the anchors not resetting in a wind shift.

[Mike OReilly]

Originally Posted by Izikalvo

Just to be clear, I am not talking about setting or resetting, what interests me is, assuming that you have the best anchor in the world that sets and hold and even makes coffee, on the holding issue, would you still prefer a heavier anchor?

It only makes theoretical sense if the absolute max force on the anchor is less than the max holding capacity. Or if it exceeds the max capacity of some other critical part of the anchor system, such as rode strength or attachment points. Only then can say you have enough anchor.


But this is all just idealized and theoretical. I've never been in an "ideal" anchorage with the "ideal" and perfectly predictable conditions. That's the real point about anchoring. In the real world the variables are many, and often difficult to predict or even know.

Given all these variables, it makes sense that you max out your anchoring system. It's the only thing that is within your full control.

[Dockhead]

Originally Posted by Izikalvo

Just to be clear, I am not talking about setting or resetting, what interests me is, assuming that you have the best anchor in the world that sets and hold and even makes coffee, on the holding issue, would you still prefer a heavier anchor?

BTW for all of you Mantus fans we have uploaded a page showing the technical differences of the two anchor designs.

Also, Steve's boat is napping, at the moment she will be in the water we will be more than happy to send him one of our smaller size anchors for testing.

I hope I didn't get in trouble with the admin here, anyway, would you trust heavier anchor to hold better? leave the rest aside, just for holding, when you know for a fact that if the anchor is not set well because of its size and might have some parts sticking out of the seabed, something that might interfere with the chain and you might get into trouble because of it?

As a hypothetical question -- if someone can make an anchor which in all respects works as well as a Spade or Mantus, but weighs less -- of course it would be great.


It's not been done, however. We all use Fortresses and kedges and know that high holding power is possible UNDER SOME CIRCUMSTANCES with light weight, but none of us sleep overnight lying to a Fortress. Because Fortresses are subject to popping out in wind shifts. Probably because they lack weight.



So if you've had some kind of engineering breakthrough and have achieved something no one has achieved before -- great, let's see it. We've never seen it before; that doesn't make it impossible. Send one of your anchors to Steve for testing. Send one to John at Morgans Cloud -- he'll test it as well. He recently tested an Australian Excel which many of us were skeptical about because of its similarity to the Delta, and John busted a few myths with his testing. If this is not mere marketing and snake oil, if you have some serious engineering breakthrough, then Stev and John will suss it out.



You say "not set well because of its size" -- this is a provocation. We don't experience anchors not setting well because of their size. Show us even one person who says his anchors set poorly because they were too big. Doesn't exist. On the contrary, the bigger and heavier the anchor, the better it sets -- according to all experience of experienced people. The only possble advantage of a lighter and/or smaller anchor, just because it is lighter and/or smaller, is handling. If you've got an invention that works well DESPITE being lighter and/or smaller, then you've got to show us. The burden of proof is on you.

[kmacdonald]

Originally Posted by noelex 77

Sorry if I misunderstood.

This post led me to understand you had experienced some problems:

I have but not because of lack of holding power. The problem is resetting reliably. A lot of you guys are sizing anchors with holding power way greater than your boat attachment points can handle. It's a waste to some degree.

[rslifkin]

Originally Posted by Dockhead

It's not been done, however. We all use Fortresses and kedges and know that high holding power is possible UNDER SOME CIRCUMSTANCES with light weight, but none of us sleep overnight lying to a Fortress. Because Fortresses are subject to popping out in wind shifts. Probably because they lack weight.

I'm not convinced that one is a weight problem. I think it's a limitation of the Danforth design. If you don't manage to get it buried far enough, it can trip out on the stock when you pull on it sideways, particularly in harder bottoms. If you manage to drag it far enough into the bottom, it's probably going to stay there (as shown by stories of them being almost impossible to retrieve after use in a heavy storm). The issue is that in many cases, particularly with a sailboat, it's hard to bury it far enough in all but a very soft bottom unless you have a ton of wind to help.

[rslifkin]

Originally Posted by kmacdonald

I have but not because of lack of holding power. The problem is resetting reliably. A lot of you guys are sizing anchors with holding power way greater than your boat attachment points can handle. It's a waste to some degree.

I think the idea isn't that you end up using all of that holding power, but it means that when you anchor in a crappy bottom or at short scope where you lose a large portion of your holding power, the amount left over is still enough. And if you've got more reserve holding, it might be less likely to break out when you pull on it in a weird direction when the wind shifts, which can avoid the need for it to reset.