Mantus and Sarca anchors

I finally got to see The Mantus and Sarca anchors in the flesh or should I say metal at the Seattle boat show. I was more impressed with the Mantus display and spent some time talking to the designer of the unit. Now I understand better why there are users who are impressed. If I had a need for another anchor I would give it a try before going full throttle in favor of the anchor. Because there are now so many good anchors on the market I can see how it might be difficult to decide which is best. Owning more than a few of these good anchors also presents a problem in the logistics of which to use where to store and how to deploy. For small light units not such a big deal but on larger boats I think it best to have one good all around performer on the bow and other light units for back up or multiple anchor situations.

Practical Sailor rates the manta in this month's edition.

The Sarca Excel in alloy make a great spare anchor. The shank slides out the bottom, and the two pieces thus become very compact for storage. The forward part of the lower section is weighted. When using a chain rode the holding power is not significantly different to the galvanised version.

SARCA in Action - anchorright.com.au

I do not know anything about the Mantus, and have never even seen one.

I do know about the SARCA Excel anchor, since I have one and have deployed it many times in a variety of conditions.

It is a Excelent anchor. It sets reliable, and has not drug that I can tell. Not much more to ask of an anchor, so I am a vary hasppy owner.

SARCA at the Seattle Boat Show

It seems Sarca is expanding its presence in USA. Were they represented by the Vancouver Island agents, or was Rex Francis there?
Sarca usually exhibits at the Sydney Boat Show, the stand is run by Rex and his wife, who I think live in Melbourne, 600km distant. It`s not a glitzy set up, but the anchors, and information, are all there.

Mantus seems to be a Rockna knock off. The difference is you can break down the Mantus for storage, but who does this. I have a 77lb Rockna and it stuck each and every time! OMG another anchor thread......

manta vs rocna/manson

Alaskan Sea-Duction said:

Mantus seems to be a Rockna knock off. The difference is you can break down the Mantus for storage, but who does this. I have a 77lb Rockna and it stuck each and every time! OMG another anchor thread......

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According to what I read in Practical Sailor, the Manta sets at 17 degrees while the setting angle on the Rocna or Manson is 32 degrees. They claim that the Manta MAY do better on hard bottoms covered with some soil - because they don't dig in as deep. In all other bottoms, it appears that a 32 degree setting angle allows the plow to dig in deeper and generally provides greater holding.

Interestingly, they also wrote this month about snubber chain hooks and how many can reduce the working load limits of chain by 25%. I have been using a plain old stainless hook and may have to rethink this.

I have used a Mantus for 3 years and have nothing but praise for it compared to the CQR it replaced. The first time I set it, I was backing down and it set so quick and firm that I thought the snubber was going to break. When retrieving the anchor, you generally have to power over it with short scope. When we sold our 38 foot trawler and moved up to the Nordic Tug, the anchor came with us. By all measurements, it is not big enough for the Nordic Tug (45 lbs) but the anchor roller won't fit anything bigger without substantial modification. Even undersized I still have confidence in the Mantus as it has held in a good bottom with winds up to 30 knots with a 4:1 scope of 1/4 inch HT chain. When I can build a pulpit to fit the 55 lb Mantus, I will probably upgrade and relegate the 45 lb to spare anchor status as I can break it down.

Tom

Ok but what is the best anchor?

No claims on best or anything else. I bought the Mantus because they shipped a 45 lb anchor to Alaska for less than $5. That impressed me. The anchor has impressed me too.

Tom

Gordon J said:

...Interestingly, they also wrote this month about snubber chain hooks and how many can reduce the working load limits of chain by 25%. I have been using a plain old stainless hook and may have to rethink this.

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Just looking at a bear claw hook bothered me. It looks to apply a concentrated load to one link. Mr Hinz didn`t think much of them either.
I have a "Sea- Dog" vertical groove plate which sits under a link. It has 2 line attachment points. I think it`s better, hopefully it does less to reduce rode strength.

On Steve's setting vids the Supreme (a scoop anchor not a plow) has'nt been bested for short scope performance. Perhaps the 32 degree "setting angle" has something to do w it. Gordon J what exactly are you refering to as "setting angle"? I have some ideas but ........

Mantus 85lb

Last spring we replaced our 66lb Bruce with an 85lb Mantus. We've been very pleased with the anchor and gear so far. Also use their bridle and swivel.

Nice company to deal with.
Tim

If my bow roller had been able to accommodate a roll bar I likely would have bought the Mantus. However, I have been exceptionally happy with my Sarca.

Excel I assume Dave.

I believe the Manson Supreme was video taped on a short scope performance.

Setting angle

Nomad Willy said:

On Steve's setting vids the Supreme (a scoop anchor not a plow) has'nt been bested for short scope performance. Perhaps the 32 degree "setting angle" has something to do w it. Gordon J what exactly are you refering to as "setting angle"? I have some ideas but ........

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Setting angle is the measurement in degrees between three shank and the plow. Imagine the shank its parallel to the bottom. The shank is zero degrees. The Mantua digs in at 17 degrees the others at 32. In other words the Mantua takes a shallower bite if bottom.

Nomad Willy said:

Excel I assume Dave.

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Yup, the Sarca Excel. I should have been more specific.

AvalonGB said:

Last spring we replaced our 66lb Bruce with an 85lb Mantus. We've been very pleased with the anchor and gear so far. Also use their bridle and swivel.

Nice company to deal with.
Tim

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Ditto us. We love it.

Ford vs Chevy lives! The anchor debate should include a Mopar or two. Just for those who like hemis. Not to mention a Buick Wildcat.

Barrett Jackson "next door" is now over. Like anchoring success, the winners were those that had savvy owners who understand preparation. Much more to it than the badge on the tail.

"Setting angle is the measurement in degrees between three shank and the plow. Imagine the shank its parallel to the bottom. The shank is zero degrees. The Mantua digs in at 17 degrees the others at 32. In other words the Mantua takes a shallower bite if bottom."

Every anchor company has its own belief/research in the angle of the shank and the fluke in their design. Generally, a narrower angle allows for "cutting into" firmer seabeds and a more wide open angle allows the fluke to present greater surface resistance to softer seabeds. A narrow angle shank/fluke does not bury as deep as one with a more wide open angle (which can or should go very deep). As a result, an anchor that is excellent in softer seabeds may be difficult to set in harder seabed substrates and vice versa. As an example, the Super MAX Anchor Pivoting arm was designed to allow the operator to set the fluke/shank angle at 19 degrees, 32 degrees, or 45 degrees. A couple years later when we found out that some operators either did not trust anchoring in extremely soft seabeds or did not want to change from the middle 32 degree setting, we designed the rigid shank model with the angle set at 24 degrees. This is an angle that works well in harder and medium seabeds but needs some extra precaution/attention to detail in extremely soft seabeds.

There are lots of reasons why an anchor works well or has some challenges in different seabeds. Fluke/shank angle is one.

Steve

Good observation on anchors and their various angles. If you are willing to do a little trigonometry, calculate the inverse of the sin of the anchor's angle of attack to a flat sea bed. This yields a minimum scope ratio needed to properly set the anchor in question. If the anchors angle of attack relative to the bottom is anything less than the anchor's designed angle, the anchor will begin to ascend instead of dive. Handy info to know when you want to break it out . It's also why many anchors don't like to set on short scope. In the case of the mantus with a 17 degree angle of attack this equates to 3.4 : 1 scope ratio. A fortress set at 32 degrees is 1.8 : 1 and set at 45 degrees will start to dive at 1.4 : 1. Scope angles shorter than this will start to break the anchor out. Best I could measure our rocna was 15 degrees and results in a 3.8 : 1 ratio. 19 and 24 degrees would yield 3 and 2.45 : 1 respectively.

cafesport said:

Good observation on anchors and their various angles. If you are willing to do a little trigonometry, calculate the inverse of the sin of the anchor's angle of attack to a flat sea bed. This yields a minimum scope ratio needed to properly set the anchor in question. If the anchors angle of attack relative to the bottom is anything less than the anchor's designed angle, the anchor will begin to ascend instead of dive. Handy info to know when you want to break it out . It's also why many anchors don't like to set on short scope. In the case of the mantus with a 17 degree angle of attack this equates to 3.4 : 1 scope ratio. A fortress set at 32 degrees is 1.8 : 1 and set at 45 degrees will start to dive at 1.4 : 1. Scope angles shorter than this will start to break the anchor out. Best I could measure our rocna was 15 degrees and results in a 3.8 : 1 ratio. 19 and 24 degrees would yield 3 and 2.45 : 1 respectively.

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I was told there would be no maths.

Excellent observation. The narrower the fluke/shank angle the longer scope required to set in the seabed. The larger the angle the the less scope because the fluke "tips or points" are already pointing down into the seabed.

Additional variables in this calculation is the slope or flatness of the seabed. The calculations assume a flat seabed and no slope or no ridges. Happen to drop on a seabed that is sloping (even slightly) toward your vessel or away from your vessel changes the required scope for fluke tip penetration in setting. Also a variable is a flat but uneven seabed. Happen to drop the anchor, even with a narrow fluke/shank angle just before a "bump up" of seabed and the fluke tip will probably penetrate the seabed with a much shorter scope.

Again, excellent observations and comments. Thanks for sharing.
Steve

Regarding flat seabeds, if you anchor say for a hurricane, and you drop the hook in the deepest part of the anchorage when and if the anchor starts to drag it will dig in deeper. The opposite happens say in Alaska.

cafesport wrote;
"It's also why many anchors don't like to set on short scope. In the case of the mantus with a 17 degree angle of attack this equates to 3.4 : 1 scope ratio. A fortress set at 32 degrees is 1.8 : 1 and set at 45 degrees will start to dive at 1.4 : 1. Scope angles shorter than this will start to break the anchor out. Best I could measure our rocna was 15 degrees and results in a 3.8 : 1 ratio. 19 and 24 degrees would yield 3 and 2.45 : 1 respectively."

Perhaps this is why The Rocna has fantastic holding power (actually only a bit more than most others) at long scope but less than others at short scope. Several anchor tests have indicated that. But the throat angle (or setting angle) functions differently during setting w anchors that lay on their sides predominantly and anchors like a Danforth or SARCA that set sitting upright. I would think that anchors like the Rocna w a narrow throat angle would set more dependably or consistently but I haven't noticed any other "laying on their side" LOTS anchors having difficulty setting. My own philosophy is that if an anchor sets dependably there's no problem w the throat angle regarding setting. The optimal throat angle for setting may not be optimal for holding when buried. And at each buried depth the optimal throat angle may be different as well. So as Steve Bedford point out the element of compromise weights heavily in anchor design.

And the length of the shank is closely related to the throat angle. I would think a long shank would be detrimental to short scope performance. And a long shank would reduce the buried fluke angle to horizontal angle. But when buried a wider throat angle would be better for holding up to a point where breaking out becomes more likely. Linda like a wing stalling on an aircraft.

cafesport said:

The opposite happens say in Alaska.

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Yes it does (BC too) , and pretty well rules our anchoring experiences. Glacial geology at work as compared to East and Gulf Coast sedimentary deposits.

On short scope/penetration...design matters as well.

Mantus anchors may have a shallower angle of attack, but 50% of the anchors weight is at the tip when laying on the sea bed, and because of the roll bar, the Mantus tip is angled downward to get to work right away.

Murray I think the roll bar angles the fluke tip up not down once the anchor is buried. Just like a headwind on a boat w a mast will pitch the bow up.

Conclusion in practical sailer: "more research is required to determine how significantly a shallow burying angle impacts holding ability... A good anchoring arsenal on a cruising boat will include at least three anchors - two on the bow suited (to) the bottoms you're likely to encounter and a reliable kedge ready to deploy."