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  #71  
Old 01-01-2013
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Re: Anchor Wars

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Originally Posted by misfits View Post
From watching the videos, pretty impressive. Forget the scope, hand setting & no chain issues, can't argue the fact that the anchor bites everytime.

Will it be avalaible in a welded version?
We don't have plans currently to make it as a one piece model, but once assembled it could be used as the solid anchor, you don't have to take it apart until the time comes to re-galvanize. It just gives you another option, and if you use anti-seize lube provided, taking the bolts off is no problem.
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  #72  
Old 01-01-2013
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Re: Anchor Wars

Guys I am off to a Race in a Regatta, so I will answer your questions when I get back tonight...
Greg
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  #73  
Old 01-01-2013
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Re: Anchor Wars

I was clear that I hadn't made my mind up by saying that I haven't bought any next gen anchor yet. I'm still shopping around on anchor model and sizing.

I still don't understand why your sizing recommendations on the small anchors are so much more conservative than they are on the mid-size anchors (or in comparison to Rocna and Manson). The holding power should be highly related to the size of the spade, correct? The spade on the Mantus 35 is only about 20% larger than the spade on the Mantus 25, but it is appropriate for boats 300% heavier? Going up one more size the blade is again about 20% larger, but the maximum boat weight only goes up by 33%. When I graph your maximum boat weights against the blade area I get a graph with very non-linear jumps. If I do the same for Rocna sizing recommendations I get a nice predictable slightly exponential curve.

The non-linearity of your recommendations don't make any sense in isolation, and make even less sense when compared to the competition. It just happens to be that my anchor size is at a point where your recommendations are the least consistent.

Happy new year and good look at the regatta today!

Last edited by Alex W; 01-01-2013 at 10:44 AM.
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Old 01-01-2013
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Re: Anchor Wars

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Originally Posted by Alex W View Post
The argument here is that Rocna is undersizing their anchors and that I should step up a size. However everywhere else on sailnet people seem to think that their recommendations are accurate......
The Rocna sizing chart is pretty good, IMO, as it allows for both length and weight, length being a proxy for windage, I assume. I can't see why an anchor cares how long the boat is. If I were bumping up against the exact upper limit for either, I would probably jump a size. Otherwise, I think some wiggle room has been built in. Also note that their chart is in Metric Tonnes, not US, therefore add about 10% to each. In my case, it calls for the same anchor whether I was 52, 59 or 66 ft. Its just a bigger tonnage margin above where I fall on the chart at 54ft. It says I should use a 40kg/88lb anchor. Bigger than the CQR I have now.

Mantus offers big blocks that combine length and weight into one. There I fall in the column that accomodates up to 60ft and 60,000 pounds, which is a 48kg/105lb anchor. If you extrapolate a 60ft/30T boat on the Rocna grid, it would suggest something between their 40kg and 55kg model.

Pretty similar in the end.
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  #75  
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Re: Anchor Wars

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Originally Posted by Alex W View Post
Mantus: Why are your recommended anchor sizes so much larger than Ronca or Manson?

I have a 7000lb empty, so probably 9-10000lb full 28' boat (Pearson 28-2). The conservative recommendation from Ronca is a Ronca 10 (10kg/22lbs) (good to 11,000lb boat). From Manson it is the similar weight Manson Supreme 25 (11.2kg/25lbs).

However the Mantus website recommends a much larger 16kg/35lbs because the 11kg/25lb model is only recommended for boats up to 5000lbs (an odd recommendation since few 30' cruisers are that light).

This immediately turned me off of your product even though some other aspects (the disassembly for instance) were nice.
Alex,

Mantus' truck test wherein he uses a tree/arm to test the anchors, the Mantus was the smaller than either the Manson or Rocna, but the test was pretty convincing in that ground/~9 lb. anchor range. Mantus vs. Manson, then Mantus vs. Rocna, showed the Mantus holding longer than the others. This was just for small anchors, of course. Maybe Mantus should repeat that test with big anchors, but he is going to need a pretty big truck. Look at the test again.

Mantus vs Rocna vs Manson Supreme, Truck with the spreader bar.mp4 - YouTube

Also, I wouldn't make too much of Rocna's website/data/videos/explanations, which are slicker and more refined. Rocna has been around a lot longer and they've had time to refine their presentations. Mantus is currently small and just getting started. In time, his presentations are likely to be refined to be as good as any. I was once told by a vendor that they could do anything, it just takes time, time and money. I suspect the same applies here in comparing the presentations.

My boat weighs 11,700 lbs. empty and is 32 ft. long. When selecting my primary anchor (before the new ones came on the scene), I looked around and the genuine Bruce was recommended. When I went to size it, my boat fell more or less at the break point....either 22 lb. Bruce or 33 lb. Bruce. I went with the larger anchor. Your loaded weight is somewhat in the same range, and Mantus' recommendation is 35 lb. (between 25 lb.and 35 lb. sizes). For your boat at 10,000 lbs., you say that the Rocna 10 recommendation is 22 lbs. for up to 11,000 lbs. Anchoring requirements are not an exact science and you are clearly at the top range of the Rocna 22 lb., so if one were being conservative, you would pick the next size up for Rocna, which would be a Rocna 15 or 33 lb. So it's all pretty much coming to the same weight point. (I did look at the 5,000 lbs. number for Mantus and I think that is probably low for the Mantus 25 lb. Don't be surprised if sometime in the future, Mantus revises that upward a bit.)

Last edited by NCC320; 01-01-2013 at 02:53 PM.
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  #76  
Old 01-01-2013
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Re: Anchor Wars

Alex, much of what NCC320 said I agree with....
hmm what can I say the 5000lbs is a typo/mistake, we made the chart in Tons (5T) bc I have a metric background and somehow a mistake was made that was not caught.... until now....
My apologies!
Otherwise we tend to be a bit more conservative simply because, we know that in poor holding ground (silt) you easily loose 70% of holding power or more.... so for you to use Mantus for an all around anchor we have to envelope worst situations and still provide secure bite for 50 knots.... This is not an exact science... We took our values for when the anchor performed the worst (i.e loose mud) and looked at the table attached plus 20% margin.
Use the table attached...
So Alex lets use your example:
28 foot boat 10,000 and we use a 25lbs Mantus.... this anchor sets in hard bottom to excess of 5000lbs, in poor holding bottom we get numbers of 1200lbs. In winds of 60 knots we expect a load on the anchor between 980-1400 lbs for your boat, so a 25 lbs Mantus might pull out...!?
These numbers are not particular to the Mantus, its true of all anchors, bottom type decides everything... there are anchors designed to handle these soft bottoms, Fortress set to 45 degrees.... SuperMax...etc
But if you make Mantus an all around anchor we want you to be safe regardless of bottom in winds up to 50 knots.... without having to rely on an auxiliary anchor...
This analysis assumes constant loads due to the wind, it does not adjust for shock loads from waves in the Harbor and gusts.... which can easily double the expected loads. (In a storm conditions like this I will always use more than one anchor)
So if you are going cruising and are planning weathering bad weather at anchor a 35 lbs Mantus is not at all unreasonable. You have to understand very little science addresses this very issue, but practical past knowledge of sailing community drives much of these recommendations.... The biggest issue is that the bottom decides everything, and "it" is not predictable nor can it be objectified for all the different places you might visit...
We get drastically different numbers for maximum holding and setting ability with changing weather in exactly the same location....
ok I lost where I was headed with all this.... Except that you caught a mistake...
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  #77  
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Re: Anchor Wars

This is the ABYC chart for your reference, some have suggested its too conservative..... but for arguments sake .... lets assume this is real....
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  #78  
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Re: Anchor Wars

Thanks for rechecking your numbers and realizing that the chart has a mistake.

I have a 7000lb (empty) boat, I'm guessing that the maximum cruising weight would be closer to 9000lbs than 10000lbs. This is a very typical ~30ft cruiser/racer with similar weight and windage to a C&C 30, Islander 30, C&C 29, Yankee 30, CAL 2-29, etc. I would expect that this is a very common class of boat that you make anchor recommendations for.

Based on the ABYC chart and your numbers (1200lbs in a loose bottom for the 25lb Mantus) it sounds like the 25lb Mantus is just fine.
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Re: Anchor Wars

No Alex, thank you for pointing it out!
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  #80  
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Re: Anchor Wars

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Originally Posted by Argyle38 View Post
This might not be the right thread, but this one seems to be the active one at the moment. My question for the OP is; how important is the roll-bar to holding strength and setting?

I have a boat with a bowsprit and my current anchor is a CQR that has the typical configuration of the fluke hanging below the bow platform and the shank extends through the platform. The other modern types of anchors with roll bars won't fit under my bowsprit, so I'm not interested in those as a primary anchor.

I find this anchor intriguing since it looks like I could remove the roll bar and it might be a drop in replacement for the CQR. I would not, however, want to make this replacement if removing the roll bar would render the anchor a step down from my CQR or even worse, useless.

Any thoughts on this?
This is an interesting question, that we get a lot... Roll-bar does not affect stting ability... In-fact, it can be used without the roll-bar, there is a possibility of the anchor flipping upside down after hitting a rock for example in such case the anchor will not set and the roll-bar protects against such event...
I have used the anchor for a year with 100% success rate on setting without the roll-bar....
Roll-bar only serves this function, flips the anchor into the correct orientation. It was an earlier prototype, before we decided to put the roll bar on.....
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Last edited by Mantus Anchors; 01-01-2013 at 09:34 PM.
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