Mantus sizing

[Roberts_s]

Dear friends,
first of all thanks to all of you for sharing your wisdom and allowing me to join your community.
I have a sailing boat Beneteau Oceanis 50 and am designing custom bowsprit with new anchor rolers so it is the best time to choose a new anchor. So far boat uses 20kg Lawrence, somewhat similar to Delta. Generally it works although sometimes I have to resettle it more than once. I took a look at "new generation anchor" manufacturer's websites and got confused for recomended sizing differences for my boat.

So it is 50ft sailing boat with max weight of 16t.
Delta recomendation - 20kg.
Rocna recomendation - 25 - 33kg (50knots, bad holding)
Manson Supreme - 25kg
Ultra - 27kg,
Sarca Excel - 22kg - 30kg
... and...
Mantus - 39kg, almost twice the weight of Delta. It's huge!!

I am stuck here. I would want to go for Mantus or Rocna, but what size should I look? I do understand all marketing tricks behind those charts but I don't think it is a matter of tricking people in Rocna website...

I asked Mantus representatives, their answer was predictable- go for the biggest. But then why Mantus, 40kg Delta would also hold a train...

Dear friends, does anyone have an explanation and/or guidance for this?

Respectfully,
Robert

[GordMay]

Greetings and welcome aboard the CF, Robert.

[Hobiehobie]

Robert. Cannot specifically answer your question but just can say we ave a 105lb Mantus holding a 24 t 54' sailboat. The anchor is large but fits well in the bow roller. All I can say is that it never ever moves. It digs in really fast and just stays there. In comparison to other recommendations Mantus does say this on their website:

"When making sizing recommendations for a working anchor we are generally referring to the needs of a cruising boat spending most of its time on anchor, in doing so we try to envelope high sustained winds (40 kts) and assume poor holding conditions (low viscosity bottoms). Some may think these recommendations to be too conservative especially when compared to sizing tables from other manufacturers. Companies often make claims of superior anchor efficiency, stating that their small anchor X will outperform a much heavier anchor from their competitors and often use sizing charts as a marketing tool to that end, recommending anchors and anchor systems that are dangerously undersized for their intended use. Comparing surface area can be a good judge for potential holding capability."

Hope that helps. We are happy and confident that we made a good choice...and the Mantus customer service is outstanding. I have a feeling most of the new generation anchors perform very similarly. They are more efficient than those preceding, but that does not mean that getting one with the largest surface area you can fit is not still the best insurance policy when stuck in a blow on the hook!

[a64pilot]

You will get several varying opinions. Mine is based on expected use, if your boat lives in a Marina and you day sail her and the likelihood of being at anchor in a major storm is very remote, then go small and save the money and weight, however if you plan on living at anchor where ducking into a Marina may not always be an option, then go for the biggest anchor your boats gear can handle.
I have a smaller boat and started with a 25Kg Rocna, which always held, but have now gone to a 40 Kg Rocna, for that very rare major storm that I hope to never be in. It is overkill, but my boat handles it fine, and in the great scheme of things as large as it is, its only 15 Kg difference in weight on the bow. Actually its 40 Kg more as I kept the 25 up there, and I can tell no difference in how the boat sails

[DDabs]

For a Beneteau 50 I'd go for the 85 lb., that's just my opinion

[Cotemar]

My vote would be to skip any of the Plow anchors you show in your list and only educate yourself with the New Generation anchors.
Rocna 25 - 33kg
Manson Supreme - 25kg
Ultra - 27kg,
Mantus - 39kg

[UNCIVILIZED]

Since you're designing your anchor roller setup from a blank page, it only makes sense to build it around the biggest anchor you think that you'd ever use. Well, perhaps even a size or three larger. And not just a new gen anchor, but figure that at some point in the boat's life you/the boat may wind up using one of the older designs that's good in rock & kelp/weeds. Which, they rely on size & mass more than more modern hooks, & thus are a bit bigger, & more unwieldy. Ergo a bigger, more accommodating anchor platform & roller are needed for them.

You can get the dimensions of most anchors pretty easily, & even print out templates for some. Which, since the fabrication of a custom sprit/roller is pretty expensive, then it might be worth it to make the wooden versions of any anchors that you're not sure of their 3D dimensions, & how they'd fit a roller. So that you can also mock up your roller design & test them in it. Cheap plywood, a hot glue gun, & PVC pipe are handy for making mockups from.

One other thought on the roller is that on some boats they're a handy spot to attach the tack of a spinnaker or Code 0 to. So then a roller/sprit needs to also be set up to resist some pretty heavy upwards loads. Huge ones if you're using a true Code 0 with purchase on the halyard or tack.

Regardless of the roller's assigned tasks (kite attachment point or no), many of us here would be more than happy to offer up design suggestions if you want to post some sketches, or diagrams. Men pretty much have DIY in our DNA

So, back to the anchor. Pick one that can "hold a train". Like a 100-something pound Mantus, or Rocna. Where's the downside? BTW, there's some stuff in the Dashew's (now free) books which can help both with anchor sizing, & roller/sprit design & construction. SetSail FPB » Free Books

[Shrew]

Since you gave LOA in Ft and displacement in T, can we assume this is 'Short Tons' (1T = 2,000lbs) and not Metric Tonnes (1T = 1,000Kg (2,204.62lb)?

Rocna: 33Kg
Mantus: 39KG

If you're really only strongly considering Rocna or Mantus, there is little point in comparing with the recommendations of Delta.

There are two schools in the 'marketing' of anchors. Some attempt to suggest the smallest possible anchor in order to achieve a more tempting price point. Some suggest a larger anchor, such as Mantus and Rocna. I sometimes feel like Ultra and Manson are trying to fit in between.

Rocna is upfront that they are upsizing the anchor for you and warn not to do it yourself. Whether you believe they are tryign to sell a larger, more expensive anchor, or whether they are advising for safety sakes is up to you.

I've used both Rocna and Manson and sized based on their recommendations and never had an issue. For something as important as an anchor, I'm not about to squabble over a few hundred dollars.

[groundtackle]

Robert S, what are your future destination plans? That is a factor.
Our recomendation would be - #6 EXCEL 65lb/30kg.
However, if you plan to cruise the world, move it up - #7 EXCEL 80lb/36kg.
There are some videos out there, selling EXCELs as a result of them. Thanks Steve.
Cotemar, perhaps you have not seen them? An open mind is wonderful thing.
ce

[evm1024]

I have 50' 16T sloop that I use a 85# Mantus on. I used to have a 80# Manson Supreme (the Manson is for sale in the PNW) on it but switched to the Mantus.

When we head out for extended cruising I will put a 105# Mantus on the boat and store the 85# for a rainy day. I'm the kind that wants the largest that the boat will handle type.

The 85# Mantus is not all that big on a 50' boat...

Any of the current "next-generation" anchors are truly outstanding and stand way above older designs. Count the Fortress in there too.

Regards

N.B. I sell Mantus anchors on the side. If you are in the PDX area you can borrow the Mantus or Manson to see how it would fit.

[Spade Anchor]

If I have the weight of your Beneteau Oceanis 50 correct at just under 30,000 lbs. Then you would require a Spade Model s120 ( 55 lbs.) (25kg).

The Spade Anchor repeatedly tests #1, in independent testing. Don't settle for a knockoff.

https://www.youtube.com/watch?v=l59f-OjWoq0

#1 Practical Sailor Feb 2013
#1 Practical Sailor Aug 2013
#1 Practical Boat Owner Aug 2011
#1 Sail Oct 2006
#1 Yachting Monthly Dec 2006
#1 Practical Sailor Jan 1999

[wyb2]

I spent a lot of time trying to pick the "right sized" anchor and eventually realized how futile it is. This is why everyone just says get the biggest, because there is little science to it. Asking "how big of an anchor do I need?" is like asking "how deep do I need to dig my well?" The first question you need to answer is "where is it going to go?" In the case of wells, you pick a spot and say right there. You can't do that with an anchor.

There is no right answer because the most important variable is bottom holding, and that's the one thing you can't know.

[cortezsailor]

I agree with the philosophy of bigger is better when it comes to anchor set up. When we talk cost the difference in price between an average size and a storm anchor is minimal when you think how much you already have invested in a boat your size .
For me with 22 500 lbs displacement, Corbin 39, I went with a Rocna 33 ( 75 lbs ) and a Mantus 65 lb as a secondary back up. I like the Mantus as a backup since I can take it apart . I can interchange either as a primary if need be.
Nothing I like better then a good nights sleep when on the hook.

[evm1024]

I'm not out long term cruising yet. My own thoughts on anchors to carry when I am are:

2 large Mantus anchors of the same size. One on the bow as the main anchor and one in spare. A large (huge?) Fortress for anytime I need inline super holding. And a smaller Fortress that is easy to handle from the dink as a kedge.

It is noteworthy that all of these anchors break down for easy storage.

The Mantus main anchor not only is a spare for itself but if it should get bent I just replace the bent part from the un-assembled one. In worst case with 2 of everything I can mix and match to put together the best of both anchors while waiting for replacement parts. (gotta love that lifetime warranty)

The hugh Fortress is well known as a named storm anchor and the small Fortress works great to give directed pulls.

N.B. I sell Mantus anchors

PS (I have a #85 Manson supreme for sell in the PDX area PM me if interested)