Mantus Anchor "Resetting"

[Andrew Troup]

Originally Posted by noelex 77

I guess part of our differences are semantics and terminology. If an anchor breaks out and moves that is dragging. Only if you are lucky will a moving anchor reset.
I don't view this as normal resetting procedure. It's not normal, or inevitable and it certainly is not reliable.

Good anchors of appropriate size in appropriate holding ground should not breakout in my view (especially while I am asleep ) and my long experience with the Rocna (and observing the performance of good anchors on other boats such as the steel Spade) indicates that this goal is achievable.

That does not mean good anchors will never drag, but accepting that your anchor will breakout every time there is a rapid 180 degree wind shift indicates to me that there is something wrong with your anchoring system.

By this important yardstick, another "good" anchor is the Bruce.

I don't have any photos, but I did a lot of field testing before adopting them, focussing on this behaviour specifically, and I've had a fair amount of experience in veering and backing winds at anchor ever since, all of which suggests that Peter Bruce succeeded in this, one of his two stated primary design aims.

in the breathless prose of the patent:

"...said stabilizing surfaces (the twisted side flukes) together being symmetrical about the said plane of symmetry such that the resultant force vector produced by the stabilizing surface lying at either side of the said plane of symmetry due to undisturbed relative movement of the mooring bed material incident at an angle to the stabilizing surface lies on a straight line which intersects the said plane of symmetry at a point aft and above a straight line containing the cable attachment point and the centre of area of the fluke member when the anchor is in a final working burial attitude whereby any rotation of the anchor about the said straight line through the cable attachment point due to a disturbing force arising when the stabilizing surfaces are buried causes an inequality between the magnitudes of the resultant force vectors produced by the stabilizing surfaces and so causes a turning moment to be established about the said straight line containing the cable attachment point acting in a direction in opposition to the direction of the rotation caused by the disturbing force."

Which makes perfect sense if you read it quick enough.

For those more visual thinkers, I have recently come across the graphic third-party depiction below, indicating that Peter and I are not the only people to have studied this, and come to a similar conclusion.

[JonJo]

I lift my hat to you Noelex, you make an excellent salesman. Two perfect anchors - how did you manage to be so lucky!

Jonathan

[noelex 77]

You forgot the Fortress and Guardian. It's probably best if we both ignore the CQR in the locker

[Andrew Troup]

Thanks for the photos, Noelex 77.
I hope you'll continue the series.

On a more flippant note: I guess in a few more years, people will be erecting movie sets around their anchors, with lights and multiple GoPro video cams, doing live capture 24/7/365

(That is, if there is anybody left actually doing it ! Maybe cruising will become another spectator sport)

[JonJo]

Originally Posted by noelex 77

You forgot the Fortress and Guardian. It's probably best if we both ignore the CQR in the locker

You have both a Fortress and Guardian? Considering your aversion why 2?

Personally I think 2 is of merit (even if one is not a Fortress, be name).

But the CQR, we have one original, one identical copy - they are both the same size and a rather larger clone. But what to do with them? I suspect a common problem. But ours are land based, gathering dust - the last place we would have them is on a yacht!

Jonathan

[noelex 77]

Originally Posted by JonJo

You have both a Fortress and Guardian? Considering your aversion why 2?

Aversion?

The Fortress is a fantastic anchor. I have said on many occasions that I think every cruising boat should have one.

To be able to row (or even using a fender swim out with) an anchor which has such great holding power is a great attribute. The aluminium construction and lack of ballast means it is very lightweight and easy to handle. It even stores flat and unbolts if you want to store it away. Fortress also provide a 'no questions asked' guarantee and will replace any bent part at no charge.

With a soft substrate the Fortress has the highest holding power of all the anchors.

On the downside, it is an anchor that occasionally breaks out when the direction of pull changes significantly. It also does not have the substrate versatility of other new generation anchors (it can be reluctant to set in weed that will not trouble other anchor designs for example). Finally if it drags (which fortunately does not happen often) it drags very rapidly, which gives little time to react if there are obstructions downwind.

For these reasons most cruisers use the Fortress as speciality stern/kedge anchor. As I do.This is where its considerable attributes shine and where the drawbacks are less important (the direction of pull is usually constant for a stern, or kedge anchor)

The Guardian is an anchor I use for the tender. The Guardian is a cheaper version of the Fortress with only a single position fluke angle no anodising and limited warrantee. As well as being cheaper (bonus in a tender where theft is more likely) the Guardian range comes in a smaller size which is more appropriate for the tender. (The smallest Fortress has a recommended boat size of 16-27 feet)

I know from previous posts you feel the Fortress resets and copes with a change in direction of pull as well as any of other new generation anchors (which is Fortress's position as well), so I guess we are destined to disagree on many aspects of anchors resetting, which is fine it would be a boring forum if everyone had the same view.

[model 10]

Originally Posted by JonJo

You have both a Fortress and Guardian? Considering your aversion why 2?

Personally I think 2 is of merit (even if one is not a Fortress, be name).

But the CQR, we have one original, one identical copy - they are both the same size and a rather larger clone. But what to do with them? I suspect a common problem. But ours are land based, gathering dust - the last place we would have them is on a yacht!

Jonathan

Well for about $30 you can cut off the shank, have a hole bored in it, buy a hefty bolt and have a pretty good 2 piece anchor to stash away.

[Andrew Troup]

Originally Posted by Guy

Well for about $30 you can cut off the shank, have a hole bored in it, buy a hefty bolt and have a pretty good 2 piece anchor to stash away.

That's an interesting idea, Guy, i reckon.

You could go one step further, broach or slot a square hole* in both the plough and the shank, use a square bar to assemble, and you've got a rough (but very strong) approximation to a collapsible Delta, maybe.

(*would cost too much to be worthwhile unless you have access to a machine shop)

[model 10]

Originally Posted by Andrew Troup

That's an interesting idea, Guy, i reckon.

You could go one step further, broach or slot a square hole* in both the plough and the shank, use a square bar to assemble, and you've got a rough (but very strong) approximation to a collapsible Delta, maybe.

(*would cost too much to be worthwhile unless you have access to a machine shop)

It would certainly jack up the cost to cut a square hole. As it was, for our 45lb CQR it cost $20 to drill a 1" hole and $10 for a 6" bolt. I'm not sure how many small machine shops could broach a hole that big and the edge distance of the hole might be getting a little slim plus, what is wrong with an articulating shank?

[Factor]

Originally Posted by noelex 77

So next time there is large wind shift don't worry that your anchor will be yanked out and have to dig itself in again. If it's a good anchor it will be doing the shuffle .

With respect, all your data says, and the only valid conclusion that can be drawn is, that that anchor, anchored in that place under those conditions did the shuffle. Nothing more.

Originally Posted by noelex 77

Anyway, I hope the photos help convince people that the "break out, rotate and then have to reset" model of anchor performance does not match the reality of the performance of a good quality anchor that is well set.

Again, not a valid conclusion. I have had plenty of anchors of all types break out, some reset, some never have a chance. Fortress surprised me once by resetting, didn't expect that, but it only surprised me once. None the less, I still bought one with my money. Because what it does well, it does brilliantly. My boat will always have a working anchor that is less likely to be clogged and thus have more chance to reset, because my data says that such instances can and do occur.

[Kenomac]

Anchoring around Guernsey a couple of years ago for several weeks using a CRR on sandy bottoms, during enormous tidal and current shifts (30 ft tides and 180 degree current shifts... My first hand observations of the anchor and rode we're no different from what your pictures show.

That doesn't mean I'd trade my oversized Ultra anchor on the anchor roller for the CQR currently located in the stern locker, but to properly test the resetting characteristics of any anchor, a mud or weed bottom would provide better data. My experience has been, that a Rocna derivative with it's roll bar, tend to clog, pull out, then fail to reset. Even the Ultra will clog with weed if allowed to drag, then fail to set. But the oversized Ultra.... And I stress oversized (heavy) seems unaffected by mud. It just buries itself again like a plow.

[model 10]

Originally Posted by Kenomac

Anchoring around Guernsey a couple of years ago for several weeks using a CRR on sandy bottoms, during enormous tidal and current shifts (30 ft tides and 180 degree current shifts... My first hand observations of the anchor and rode we're no different from what your pictures show.

That doesn't mean I'd trade my oversized Ultra anchor on the anchor roller for the CQR currently located in the stern locker, but to properly test the resetting characteristics of any anchor, a mud or weed bottom would provide better data. My experience has been, that a Rocna derivative with it's roll bar, tend to clog, pull out, then fail to reset. Even the Ultra will clog with weed if allowed to drag, then fail to set. But the oversized Ultra.... And I stress oversized (heavy) seems unaffected by mud. It just buries itself again like a plow.

I'm a little confused why a larger anchor would sink/dig in better than a smaller one. A larger anchor is bigger and has more surface area. It seems like they would dig in about the same per pound. The surface area would only come into play if it was going to drag.
By the way, the Ultra is a pretty good looking anchor whereas I think the bolt together Mantus would look like a wart on my bow.

[JonJo]

Originally Posted by Kenomac

It just buries itself again like a plow.

I suspect you use of words was accidental - but I cannot resist!


If only all anchors buried themselves like a plough

Jonathan

[Kenomac]

Originally Posted by Guy

I'm a little confused why a larger anchor would sink/dig in better than a smaller one. A larger anchor is bigger and has more surface area. It seems like they would dig in about the same per pound. The surface area would only come into play if it was going to drag.
.

One word: Gravity. I'm a believer in gravity... Bigger is better. Our boat weighs 25 tons, nobody is going to convince me that smaller (lighter) is a better choice... I took physics.

If I had some dinky, undersized anchor plugged up with mud, right up to its eyesore roll bar, there's no way the thing is going to dig back in. It would be like trying to dig in a small ball of mud. The Ultra doesn't have a roll bar plus the weighted tip curves downward to grab. Without the roll bar, it's able to shed the mudball over the fluke unlike the roll bar types. However, clogged with weed or grass, none of the designs will reset without first removing the debris. But again, without the roll bar, the Spade and ultra have a better chance of digging and turning like the photos of the Mantus in sand.

[Andrew Troup]

Originally Posted by Guy

... what is wrong with an articulating shank?

I read on the www (on this very forum, IIRC, so it MUST be right !) that the makers of CQR did some tests when the success of the one-piece Bruce design started to really carve into their podium position, with the result that they came up with the one-piece Delta, which (in all their own tests) held better in practice.

I continue to understand how they could have believed the articulated shank would hold better in theory, and I occasionally wonder if a limited degree of articulation (with a stiff "Duratorque" type connection to provide strong self-centering) might combine the stability of a rigid shank with the tolerance to small directional changes of the hinged one - but it fails the important 'simplicity' test.

I would personally never bother making that adaptation to a plough or spade anchor, but it does seem tempting to try to come up with a better rock and weed anchor.

With regard to the 'good holding' bottoms most anchors are optimised for, I sometimes wonder if we are at or near some dotted line of 'diminishing returns' in our search for raw holding power.

Not a very good analogy, I know, but we don't see that many supersonic passenger planes these days.

Pursuing narrow 'measures of merit' does not lead inexorably to nirvana.