Rocna 55 (121lb) vs Mantus M1 (125lb)

[hpeer]

I have a Mantus 125 pound and am very pleased with it.

But Nolex as your answer, he has experience with both.

I can only add this, the Mantus is cheaper to buy, but also should e cheaper to SHIP. Because it can be knocked down it takes up less space.

So the price difference is even bigger in the Mantus favor.

[ranger58sb]

Originally Posted by jordanbigel

Maybe that means a Spade instead of a Mantus or a rollbar-Rocna, I am considering all options at this point, even though this thread was started to learn more about the comparison between these 2 specific anchors.

Conceptually, the Vulcan just seems to me to be like a one-piece Spade.

And that's actually one of the reasons we got a Vulcan 40 instead of a Spade. (Informed by a review of Steve Goodwin's various tests.)

-Chris

[SailFastTri]

Originally Posted by ranger58sb

Conceptually, the Vulcan just seems to me to be like a one-piece Spade.

And that's actually one of the reasons we got a Vulcan 40 instead of a Spade. (Informed by a review of Steve Goodwin's various tests.)

-Chris

I'm of the same view.

I think the only advantage of a rollbar type anchor over the Vulcan or Spade is in the flatter tip of the fluke design: The weighted-tip anchors have a thicker more triangular tip cross-section vs the flat shovel-like blade of the rollbar anchors. I believe that smaller tip cross-section might translate into better penetration into hard-packed sand bottoms. It also translates into more fluke surface area per pound of anchor (the Danforth/Fortress advantage).
However, once sufficient penetration is achieved, the hoop might be a limiting factor for further penetration in storm-force conditions, and might collect a ball of material that could inhibit re-setting.

[Shrew]

Originally Posted by SailFastTri

I'm of the same view.

I think the only advantage of a rollbar type anchor over the Vulcan or Spade is in the flatter tip of the fluke design: The weighted-tip anchors have a thicker more triangular tip cross-section vs the flat shovel-like blade of the rollbar anchors. I believe that smaller tip cross-section might translate into better penetration into hard-packed sand bottoms. It also translates into more fluke surface area per pound of anchor (the Danforth/Fortress advantage).
However, once sufficient penetration is achieved, the hoop might be a limiting factor for further penetration in storm-force conditions, and might collect a ball of material that could inhibit re-setting.

While a little late to this discussion, i'll throw in my anecdotal observations....

I've owned and anchored extensively with the Traditional (rollbar) Rocna, Manuts Supreme, and Rocna Vulcan. I use the Mantus on my smaller Boston Whaler. The Rocna Vulcan is the main bower.

I've only ever dragged once and that was with the Rocna Vulcan. Admittedly, I was short scoped and we had 30+ mph with higher gusts. I've also only ever had 2 problems setting, and both times that was with the Rocna Vulcan

This leads me to suspect that, while an extremely small difference, the Vulcan weighted tip may not roll the anchor as consistently as the rollbar.

The Rocna's have a 'v' shape in the fluke that can pack in mud and clay. The Manson's fluke is smooth and the Mantus has two creases with wider radius'. The Manson wouldn't pack in the clay (same anchorages) that the Rocna did. This always made me wonder if this would impair a reset?

I really only use the small Mantus in sand, so I can't account for how mud and clay pack in. I use this to anchor off of beaches. I'm not sure how much I trust a bolt to sleep at night.

I still love all three for over all performance.

[SailFastTri]

Originally Posted by Shrew

While a little late to this discussion, i'll throw in my anecdotal observations....

I've owned and anchored extensively with the Traditional (rollbar) Rocna, Manuts Supreme, and Rocna Vulcan. I use the Mantus on my smaller Boston Whaler. The Rocna Vulcan is the main bower.

I've only ever dragged once and that was with the Rocna Vulcan. Admittedly, I was short scoped and we had 30+ mph with higher gusts. I've also only ever had 2 problems setting, and both times that was with the Rocna Vulcan

This leads me to suspect that, while an extremely small difference, the Vulcan weighted tip may not roll the anchor as consistently as the rollbar.

The Rocna's have a 'v' shape in the fluke that can pack in mud and clay. The Manson's fluke is smooth and the Mantus has two creases with wider radius'. The Manson wouldn't pack in the clay (same anchorages) that the Rocna did. This always made me wonder if this would impair a reset?

I really only use the small Mantus in sand, so I can't account for how mud and clay pack in. I use this to anchor off of beaches. I'm not sure how much I trust a bolt to sleep at night.

I still love all three for over all performance.

A bit confusing... did you mean to write Manson or Mantus?

[Tortuga's Lie]

Originally Posted by Shrew

While a little late to this discussion, i'll throw in my anecdotal observations....

I've owned and anchored extensively with the Traditional (rollbar) Rocna, Manuts Supreme, and Rocna Vulcan. I use the Mantus on my smaller Boston Whaler. The Rocna Vulcan is the main bower.

I've only ever dragged once and that was with the Rocna Vulcan. Admittedly, I was short scoped and we had 30+ mph with higher gusts. I've also only ever had 2 problems setting, and both times that was with the Rocna Vulcan

This leads me to suspect that, while an extremely small difference, the Vulcan weighted tip may not roll the anchor as consistently as the rollbar.

The Rocna's have a 'v' shape in the fluke that can pack in mud and clay. The Manson's fluke is smooth and the Mantus has two creases with wider radius'. The Manson wouldn't pack in the clay (same anchorages) that the Rocna did. This always made me wonder if this would impair a reset?

I really only use the small Mantus in sand, so I can't account for how mud and clay pack in. I use this to anchor off of beaches. I'm not sure how much I trust a bolt to sleep at night.

I still love all three for over all performance.

Is it a Manson Supreme or a Mantus M1? Two totally different anchors as the Manson is one piece and a slot to allow for backing out your anchor while the Mantus is three pieces bolted together.

The other thing about Mantus that has not yet been mentioned is the second-to-none customer service, when you call them up, they are eager to help out and Greg Kutsen (owner) is likely to be the one picking up the phone.

[wrwakefield]

Originally Posted by jordanbigel

Sigh...

Maybe that means a Spade instead of a Mantus or a rollbar-Rocna, I am considering all options at this point, even though this thread was started to learn more about the comparison between these 2 specific anchors.

My experience (and that documented by many others) is that there are far fewer differences in performance (consistency) between the next heavier category of 'modern yacht anchors' (e.g., 45-60+ kg) compared to the same anchor designs of half- or even a quarter of- that weight range.

This also applies to some of the older anchors not considered of modern design. For instance, try to convince any experienced cruiser with a 45+kg genuine Bruce that any anchor is better. (Or try to prove it...)

This led us to choose (after consulting with the manufacturer) a 45kg Spade as our primary bower for our 43 foot ketch (our bowsprit won't accommodate rollbar anchors.) It always sets 'immediately' (likely due to 45% of the weight being in the tip.)

This is 33% heavier than that suggested by the manufacturer's sizing charts (+2 sizes.) It has been a stellar performer for us in our full time use in higher latitudes; allowing us to anchor (when needed) in what might otherwise be marginal bottom types for lighter weight versions of the same- or similar modern anchor designs.

We also chose chain to match the boat size; 5/16" G43. This allows us to carry 550 ft in the anchor locker to facilitate deep water anchoring.

I think our ground tackle sizing choice is proportionally similar to what you are considering, so I offer this as food for thought.

Cheers, Bill

PS: If you are interested in more details about our ground tackle selection process, see our Ground Tackle Inventory page. (No ads; no begging...)

[Dockhead]

Originally Posted by wrwakefield

My experience (and that documented by many others) is that there are far fewer differences in performance (consistency) between the next heavier category of 'modern yacht anchors' (e.g., 45-60+ kg) compared to the same anchor designs of half- or even a quarter of- that weight range.

This also applies to some of the older anchors not considered of modern design. For instance, try to convince any experienced cruiser with a 45+kg genuine Bruce that any anchor is better. (Or try to prove it...)

This led us to choose (after consulting with the manufacturer) a 45kg Spade as our primary bower for our 43 foot ketch (our bowsprit won't accommodate rollbar anchors.) It always sets 'immediately' (likely due to 45% of the weight being in the tip.)

This is 33% heavier than that suggested by the manufacturer's sizing charts (+2 sizes.) It has been a stellar performer for us in our full time use in higher latitudes; allowing us to anchor (when needed) in what might otherwise be marginal bottom types for lighter weight versions of the same- or similar modern anchor designs.

We also chose chain to match the boat size; 5/16" G43. This allows us to carry 550 ft in the anchor locker to facilitate deep water anchoring.

I think our ground tackle sizing choice is proportionally similar to what you are considering, so I offer this as food for thought.

Cheers, Bill

PS: If you are interested in more details about our ground tackle selection process, see our Ground Tackle Inventory page. (No ads; no begging...)

Yeah. Bill can correct me if I'm misinterpreting him, but I think he's talking about the "100 lb anchor effect".


When anchors reach (and exceed) 100 lbs or 45kg, they start to work better entirely disproportionately to their weight.


All experienced cruisers note this although there is no scientific explanation. But I think there could be a scientific explanation if someone would delve into it. It could be some kind of scale effect in soil mechanics.



Dashew nailed it, decades ago -- "when everyone laughs at your anchor, it might be barely big enough". Size is king with anchors. The best formula for happiness at anchor is to use the heaviest anchor you can possibly carry, whatever design it is.

[Jammer]

Re the OP, interesting short list of two anchors.

Several sailors who have used the Rocna extensively have reported rare but serious problems with the anchor failing to reset on a wind shift in soft mud. I have recently purchased a Vulcan and believe it is a better design. Perhaps the Mantus is also. I think the kinds of tests that can be performed objectively are unlikely to smoke out problems that occur infrequently and only in certain bottom types, and so as valuable as they are I do not see the comparison tests as the last word.

Cost, local availability, warranty service, build quality, durability, and size of installed base also matter.

I think the Spade is a better performing anchor but bought a Vulcan because they are somewhat cheaper, can be more readily regalvanized, are easier to inspect, and do not have problems with internal corrosion. The differences in performance are minor.

[wrwakefield]

Originally Posted by Dockhead

Yeah. Bill can correct me if I'm misinterpreting him, but I think he's talking about the "100 lb anchor effect".


When anchors reach (and exceed) 100 lbs or 45kg, they start to work better entirely disproportionately to their weight.


All experienced cruisers note this although there is no scientific explanation. But I think there could be a scientific explanation if someone would delve into it. It could be some kind of scale effect in soil mechanics.



Dashew nailed it, decades ago -- "when everyone laughs at your anchor, it might be barely big enough". Size is king with anchors. The best formula for happiness at anchor is to use the heaviest anchor you can possibly carry, whatever design it is.

DH,

The "100 lb anchor effect" is a great way of describing the beginning of parity between 'modern' anchors.

Thanks for the clarity.

I suspect there may be yet other anchor weight effect gradations (exponential?) in the next heavier anchor range I have less experience with: e.g., 100+kg anchors on the next category of yachts. (e.g., 25+m)

And I concur from experience: anchor size is paramount in one's ground tackle system.

Cheers, Bill

[Panope]

I have conducted several tests that might shed some light on the alleged "100lb anchor effect".

In a "soft mud" seabed, I tested 5 Genuine Bruce anchors from 11 lbs. to 116 lbs. All of the anchors set reliably and remained engaged. I found very little "Boost" in holding performance ratio with the largest anchor. Holding power to anchor weight ratios were as follows:

5kg - 25
15kg - 14
20kg - 12
30kg - 11
50kg - 15

Note: The Best (non pivoting fluke, 45lb range, steel) anchors in this seabed had holding/weight ratios of about 20.

-------------------------------

In a "cobblestone" seabed (Grapefruit Size), I found the 50kg Bruce to have zero "boost" in holding performance ratio over a 20kg Bruce. Both anchors had the same Holding/Weight ratio:

20kg - 3.4
50kg - 3.4

Note: The Best anchor in this seabed had a Holding/weight ratio of 16.5

------------------------------

In a "Sandy Mud" seabed, I tested 6 Genuine Bruce anchors from 11lbs to 116lbs. I found the largest anchor to have a significant boost in performance over the "medium sized" anchors and only a slight boost over the smallest.

All of the anchors set reliably (initially) but had full "pop-out" releases immediately following their peak holding. None of these were able to "reset" fully and repeat their max hold due to the presence of seabed on the fluke. However, the largest (50kg) was the closest to achieving a proper, upright reset.

Hold/Weight:

5kg - 25
10kg - 24
15kg - 24
20kg - 16
30kg - 17
50kg - 28

Note. The best (non pivoting fluke, 45lb range, steel) anchors have Holding/Weight ratios over 100
-------------------------------

In Sandy Mud seabed, I tested Forfjord anchors in 65lb. and 350lb. sizes. I found the larger anchor to have significantly less holding (ratio) than the smaller anchor. Both anchors set reliably (initially), had partial releases immediately following max hold, and an inability to repeat their max hold.

65lb - 14
350lb- 9

-----------------------------

On a wet sand beach, I experimented with anchors ranging from 10 lbs to 55 pounds and found the larger anchor had far better weed penetration than the smaller anchors.

-----------------------------

While I have no trouble believing that larger anchors could be vastly better at penetrating difficult bottoms (hard sand, weed, etc.), I have serious doubts that a large boost in performance (ratio) exists over smaller anchors that are able to engage the seabed.

I need to do much more testing before a definitive conclusion (about anchor scaling) can be made. Chances are, the answer to the question will end up like most other anchor related questions: It depends.

Steve

[Dockhead]

Originally Posted by Panope

I have conducted several tests that might shed some light on the alleged "100lb anchor effect".

In a "soft mud" seabed, I tested 5 Genuine Bruce anchors from 11 lbs. to 116 lbs. All of the anchors set reliably and remained engaged. I found very little "Boost" in holding performance ratio with the largest anchor. Holding power to anchor weight ratios were as follows:

5kg - 25
15kg - 14
20kg - 12
30kg - 11
50kg - 15

Note: The Best (non pivoting fluke, 45lb range, steel) anchors in this seabed had holding/weight ratios of about 20.

-------------------------------

In a "cobblestone" seabed (Grapefruit Size), I found the 50kg Bruce to have zero "boost" in holding performance ratio over a 20kg Bruce. Both anchors had the same Holding/Weight ratio:

20kg - 3.4
50kg - 3.4

Note: The Best anchor in this seabed had a Holding/weight ratio of 16.5

------------------------------

In a "Sandy Mud" seabed, I tested 6 Genuine Bruce anchors from 11lbs to 116lbs. I found the largest anchor to have a significant boost in performance over the "medium sized" anchors and only a slight boost over the smallest.

All of the anchors set reliably (initially) but had full "pop-out" releases immediately following their peak holding. None of these were able to "reset" fully and repeat their max hold due to the presence of seabed on the fluke. However, the largest (50kg) was the closest to achieving a proper, upright reset.

Hold/Weight:

5kg - 25
10kg - 24
15kg - 24
20kg - 16
30kg - 17
50kg - 28

Note. The best (non pivoting fluke, 45lb range, steel) anchors have Holding/Weight ratios over 100
-------------------------------

In Sandy Mud seabed, I tested Forfjord anchors in 65lb. and 350lb. sizes. I found the larger anchor to have significantly less holding (ratio) than the smaller anchor. Both anchors set reliably (initially), had partial releases immediately following max hold, and an inability to repeat their max hold.

65lb - 14
350lb- 9

-----------------------------

On a wet sand beach, I experimented with anchors ranging from 10 lbs to 55 pounds and found the larger anchor had far better weed penetration than the smaller anchors.

-----------------------------

While I have no trouble believing that larger anchors could be vastly better at penetrating difficult bottoms (hard sand, weed, etc.), I have serious doubts that a large boost in performance (ratio) exists over smaller anchors that are able to engage the seabed.

I need to do much more testing before a definitive conclusion (about anchor scaling) can be made. Chances are, the answer to the question will end up like most other anchor related questions: It depends.

Steve

Well, there's the science, which I certainly can't argue with.

Yet everyone I know or even heard of with experience of 100+ lb anchors notices this. Maybe it's not a matter of ultimate holding power, but rather, setting behavior?

[Muaddib1116]

Originally Posted by Dockhead

Yet everyone I know or even heard of with experience of 100+ lb anchors notices this. Maybe it's not a matter of ultimate holding power, but rather, setting behavior?

That would make some sense I think. For many boats that can carry ~100lb anchors, the ultimate holding of a 77lb version, with a good set and consistent wind angle, is probably sufficient, even in high winds. But for any given seabed, it's initial set and reset-ability should be much better in the heavier version. A lot of boats that can carry ~100lb anchors probably came from the factory with 60-80lb anchors and have been upgraded to ~100lb anchors and the users have noted a big increase in "performance".

[noelex 77]

Originally Posted by Panope

While I have no trouble believing that larger anchors could be vastly better at penetrating difficult bottoms (hard sand, weed, etc.), I have serious doubts that a large boost in performance (ratio) exists over smaller anchors that are able to engage the seabed.

Thanks for the good work Steve. Professor Knox has also done a great deal of work in this area, testing a large number of popular designs such as the Spade, Rocna, CQR etc over several sizes. As your results have suggested, he found the ratio of holding power to anchor weight stayed roughly constant.

It is important to understand that this does not mean large anchors do not have an advantage, but rather that an anchor’s holding ability rises linearly with weight. In other words, a 40kg anchor will have twice the holding ability of a 20 kg anchor.

I agree completely with your statement about difficult substrates. In substrates such as weed, gravel/stones, coral rubble etc the larger anchor has a significant extra advantage. This is more than the rise in weight would suggest. The obstacles impeding the anchor such as the weed and its roots stay the same size no matter what anchor size is selected by the boat owner. A larger anchor finds these impediments less of an issue than a smaller anchor. Therefore the holding power rises more rapidly than linearly with weight. This mechanism is likely producing the practical differences Dockhead is reporting.

More boats drag because of poor performance caused by a marginal substrate than anything else so the boost in performance produced by large anchors has very significant real world benefits.

[noelex 77]

……xxxxxx