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

[jordanbigel]

I'm trying to up-size my anchor (currently Rocna Vulcan 40) - I'm planning to keep the Vulcan as a backup/second hook, but I want my primary to be bigger.

I'm looking at 2 options -

1. Rocna 55 (121lb)
2. Mantus M1 (125lb)

From what I can see they both have huge and loyal followings. I've seen dozens of Panope videos and both seem to come out looking good, but are there pros and cons when comparing these two designs?

It appears the main difference is that the Mantus is constructed of 3 pieces bolted together, while the Rocna is a (more traditional) singe forged piece of steel. My instinct is to go with the Rocna based on only my preconceived notion that bolts are a weak point compared to having 1 piece of steel.

The Mantus is also $500 less expensive. They tout this as "modular" - is that because they want you to be able to replace a broken part of it without tossing the entire thing? Does that happen? I'm having a hard time accepting the Mantus is as good as a single piece Rocna. Am I missing something?

Note: I know this is a photo a smaller Rocna, but the design is the same and I could not find a photo of the 50kg model.

[SailingHarmonie]

My personal opinion is that with all of the modern anchor designs if they are of similar surface area and weight, anchoring technique trumps the relatively minor differences in anchor performance from design. Pay attention to scope, use a GOOD snubber that actually stretches, and do not ignore the bottom you chose. All of these make more difference to your success than the difference between Rocna, Mantus, Spade, etc....

That said, we upgraded our 53 foot, 38,000 pound ketch from a Rocna 40 to a Mantus M1 105lb. It's better, no question. But the boat has been around the world with the Rocna, so it certainly was not BAD. But the Mantus is bigger. So of course it is better.

Fitting a 120 lb anchor from any vendor would have been a nightmare, hence the 105 lb choice. So far the Mantis has held in 55 knot squalls and 72 knot hurricanes. We're happy.

Either choice and you'll sleep well. Nobody, but NOBODY ever work up at 2AM with a squall howling worried that their anchor was too big.

[jordanbigel]

The 105lb Mantus is also an option for me, if I cannot fit the bigger one - but wanted to try and focus the responses on the question of what is different about the design (given 2 similar size anchors).

[Montanan]

The Mantis is as strong at its four nuts and bolts holding the shaft; the Rocna is as strong as its weldment holding the shaft.

One may desire to periodically check the tightness and / or replace the nuts and bolts on the Mantis using the $500 savings for preventive maintenance.

Both solid anchors.

Bon voyages and bon anchorages.

[Lee Jerry]

On our previous boat, Tayana 52, we had the 100 lb Mantus Supreme. IIRC (it was a decade ago), this was like 1/2 size up from the recommended (low end of the range, whereas the next size down had the boat listed in the high end). Was very happy with the anchor, never dragged between SE US to Australia.

We recently acquired a new (to us) boat. I expect I'll be buying another Mantus soon.



Not to get political, but is Rocna still manufactured in China? But that's why I bought a Mantus then.

[SailFastTri]

Originally Posted by Lee Jerry

On our previous boat, Tayana 52, we had the 100 lb Mantus Supreme. IIRC (it was a decade ago), this was like 1/2 size up from the recommended (low end of the range, whereas the next size down had the boat listed in the high end). Was very happy with the anchor, never dragged between SE US to Australia.

We recently acquired a new (to us) boat. I expect I'll be buying another Mantus soon.



Not to get political, but is Rocna still manufactured in China? But that's why I bought a Mantus then.

Not to get political? Where’s the Tayana built?

[Lee Jerry]

Originally Posted by SailFastTri

Not to get political? Where’s the Tayana built?

Ha!

Taiwan - is that considered China?

In 1989 - I bought it used in 2011, in FL, USA, so my money went where?

[SailingHarmonie]

Originally Posted by Lee Jerry

Ha!

Taiwan - is that considered China?

In 1989 - I bought it used in 2011, in FL, USA, so my money went where?

Who would have thought there was a way to make an anchor thread even more dogmatic and opinionated than usual!

[SailingHarmonie]

Originally Posted by jordanbigel

The 105lb Mantus is also an option for me, if I cannot fit the bigger one - but wanted to try and focus the responses on the question of what is different about the design (given 2 similar size anchors).

If you go with the 105lb range you'll have to go Mantus, Rocna skips over that size range.

If you go to 120, my opinion is the difference is so small, you'll not notice the difference. Other people will disagree, sometimes with great passion, but no real data.

[SailFastTri]

Originally Posted by SailingHarmonie

Who would have thought there was a way to make an anchor thread even more dogmatic and opinionated than usual!

Apparently I missed the essential thrust of the comment I questioned. My apologies to all for wasting digital ink on this foible.

Getting back to the anchor question - I’ve owned a Rocna 44 pounds, and used it for about 12 years (I had the pre-China version made under license by Canada Metals in Canada). It only dragged in soft mud. It came up with half the bottom of every anchorage, so I’d say it’s essential to have a washdown pump if you use one (probably the same with other hoop anchors).
Steve Goodwin does an excellent series of anchor tests on YouTube (his channel is called SV Panope). He rates the Mantus much higher than Rocna in his tests, which seem to be objectively conducted. I’d choose the Mantus over Rocna for that reason. Search for his Rocna and Mantus test videos and draw your own conclusions.
Edit: corrected Steve Goodwin’s name

[jordanbigel]

Originally Posted by SailFastTri

Apparently I missed the essential thrust of the comment I questioned. My apologies to all for wasting digital ink on this foible.

Getting back to the anchor question - I’ve owned a Rocna 44 pounds, and used it for about 12 years (I had the pre-China version made under license by Canada Metals in Canada). It only dragged in soft mud. It came up with half the bottom of every anchorage, so I’d say it’s essential to have a washdown pump if you use one (probably the same with other hoop anchors).
Steve Goodwin does an excellent series of anchor tests on YouTube (his channel is called SV Panope). He rates the Mantus much higher than Rocna in his tests, which seem to be objectively conducted. I’d choose the Mantus over Rocna for that reason. Search for his Rocna and Mantus test videos and draw your own conclusions.
Edit: corrected Steve Goodwin’s name

Thanks - I did watch a ton of Panope videos about 2 years ago, I did not recall that he rated the Mantus migh higher, and I do consider that to be objective evidence and of great weight. Will review those videos!

[nmuir]

Originally Posted by jordanbigel

It appears the main difference is that the Mantus is constructed of 3 pieces bolted together, while the Rocna is a (more traditional) singe forged piece of steel. My instinct is to go with the Rocna based on only my preconceived notion that bolts are a weak point compared to having 1 piece of steel.

Have had Mantuses (or is plural Mantai? ) for over a decade, and purchased them over Rocnas based on the online tests others have mentioned.

The bolts have never caused any issues or been a source of concern for me.

As other have said, both are great anchors compared to the older generation ones. I don't think you can go wrong.

[jordanbigel]

Originally Posted by nmuir

Have had Mantuses (or is plural Mantai? ) for over a decade, and purchased them over Rocnas based on the online tests others have mentioned.

The bolts have never caused any issues or been a source of concern for me.

As other have said, both are great anchors compared to the older generation ones. I don't think you can go wrong.

Good to hear! Thanks.

[Panope]

Originally Posted by jordanbigel

Thanks - I did watch a ton of Panope videos about 2 years ago, I did not recall that he rated the Mantus migh higher, and I do consider that to be objective evidence and of great weight. Will review those videos!

I have conducted comparison tests in 8 different seabed types. In 7 of these, the Mantus M1 performed the same or better than the Rollbar Rocna. In the 1 seabed where the Rocna was better, the advantage was only slight.

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In terms of physical strength, the Rocna is significancy better. The Mantus M1 rollbar is more susceptible to bending (in normal seabeds) when subjected to extremally high loads, think hurricane force winds (Greg from Mantus, told me that he has replaced a small handful of bent rollbars out of many thousands). Also, the Mantus toe might be more susceptible to bending during retrieval if caught under an immobile object (boulder, concrete block, etc.)

The bolted connections of the Mantus M1 are well engineered and are very unlikely to fail unless the bolts are heavily corroded. I do not consider the bolted connections to be a structural weakness.

Note that oversizing any anchor has the benefit of diminishing construction weaknesses. The "smaller" boat just won't generate the loads necessary to bend the anchor.

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Both anchors have hollow rollbars that have the potential of trapping mud and rusting from the inside out. I have seen at least one picture of a Rocna with a fully perforated rollbar.

Every single time that I test a hollow rollbar anchor in soft mud, the rollbar becomes impacted with seabed (they all have openings at the bottom). Only a powerful jet of water applied BEFORE the seabed dries/hardens, will clear this debris.

Note that the Mantus Rollbar is easily replaceable.

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I try very hard to NOT make any recommendations about what anchor products people should buy or how to use them.

My focus is to gather information about anchors and anchoring that may not be readily available, and then report the findings.

Steve

[Orion Jim]

Originally Posted by jordanbigel

It appears the main difference is that the Mantus is constructed of 3 pieces bolted together, while the Rocna is a (more traditional) singe forged piece of steel..

BOTH are comprised of three components. The Mantus is bolted together and the Rocna is welded, not forged.
My personal preference is a Spade but my kedge is a Mantus. The Spade stays on the bow roller but i disassemble the Mantus when headed offshore and reassemble it when approaching my destination. I carry a couple extra sets of bolts. In use I have found the Mantus will dig in almost immediately and it has always held firmly, resetting itself without any issues. My preference still remains the Spade.