Mantus Anchors

FF wrote;

"Would be interesting to see if the steel version broke before the aluminum copy."

Broke the metal or broke out?

Motion 30,
Yup I'm sure he was very accommodating. Is a 105lb anchor on your size boat average?

Brian,
Why don't you make steel anchors? And what is the stock for? It seems obvious but a number of Danforth types don't have stocks.

FF,

The US Navy included a 90 lb Danforth H-3600 model in their 1989 test, along with the 47 lb Fortress FX-85, and these anchors are almost identical in physical size.

The sea bottom was sand/clay, and the Danforth held to 9,000 lbs and under "Reason for Test Termination," the US Navy noted: "Anchor Pulled Out - Structural Damage"

The FX-85 held to 10,200+ lbs, and under "Reason for Test Termination," they noted, "Test Stop, Anchor Held - Shank Bent on Retrieval"

Two other Danforth models were tested, the T-6000 and T-7000 of the "Deepset II" model series, and they also pulled out during their tests due to structural failure.

The Fortress models FX-55 and FX-125 were tested as well. In the same sand/clay bottom, the smaller 32 lb FX-55 pulled out at 8,800 lbs in the first test, and in a second test, it held to 10,600 lbs when they stopped the test. The 69 lb FX-125 held to 14,600 lbs when they stopped the test due to the engines overheating aboard the testing vessel.

Afterwards, the US Navy wrote this in their summary report:

"The fact that the Fortress anchors incurred no significant structural damage at such high holding ratios suggest that the anchors have been extensively engineered from both the hydrodynamic and structural standpoints."

And also:

"Under anticipated loading conditions, NAV-X (corporate name) has compensated for aluminum's susceptibility to deformations through careful structural design of their anchors."

Regards,
Brian

manyboats said:

Brian, why don't you make steel anchors? And what is the stock for? It seems obvious but a number of Danforth types don't have stocks.

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Eric,

Our company founder was a lifelong boater and he started Fortress is his mid-50s. Prior to that, he had an extensive career as an engineer and he owned a couple of manufacturing companies. I think that Fortress became his passion and he had no interest in manufacturing anchors out of a different material.

The stock (narrow round rod) stabilizes the anchor once it reaches the sea bottom, and then the flukes fall forward and the anchor begins to dig in and set. If the stock is shortened or eliminated, then the anchor would have a tendency to flop from side to side until one, or both, of the flukes dug in. This would be particularly noticeable if the boat was falling back quickly due to wind or current.

Regards,
Brian

manyboats said:

FF wrote;

"Would be interesting to see if the steel version broke before the aluminum copy."

Broke the metal or broke out?

Motion 30,
Yup I'm sure he was very accommodating. Is a 105lb anchor on your size boat average?

Brian,
Why don't you make steel anchors? And what is the stock for? It seems obvious but a number of Danforth types don't have stocks.

Click to expand...

My boat is 40,000lbs. I m sure I could have used one size smaller but now I will sleep better at nite

I'm all for having a macho anchor, and I'm sure I'd be relieved to have a 100 lb. storm anchor of my choice in a big blow, but hoisting a hundred lbs. with appropriate chain is a big hoss of a weight for most cruiser windlass units. Breaking one out, lifting and carrying a hundred pounder is also considerable strain on cruiser pulpits.

Thanks Brian,
I would think the Danforth anchor would would fine w/o the stock but the stability it gives must be significant as most all Danforth types have the stock.
Why is it that commercially made Danforth's are made so light? Seems to me a Danforth could be made w a stout shank and stock but they are not available and I've never seen one.

hustler,
Lots of guys carry an extra 100lbs of chain and think nothing of it. Better that 100lbs be in the anchor where it will do much more good .... and it's more macho.

manyboats said:

Thanks Brian,
I would think the Danforth anchor would would fine w/o the stock but the stability it gives must be significant as most all Danforth types have the stock.
Why is it that commercially made Danforth's are made so light? Seems to me a Danforth could be made w a stout shank and stock but they are not available and I've never seen one.

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Eric,

I checked Danforth's site and for their Hi-Tensile (H) series, they manufacture anchors from 5 to 190 lbs. Regarding the stout shank and stock, the only anchor of this type that I know of which meets this description is the US Navy Stockless anchor, and they are beastly heavy. Washington Chain & Supply, an occasional customer of ours, sells them and below is a link:

US Navy Stockless

Brian I had no idea the Navy anchors were considered Danforth types. That would include my Dreadnought too I spoze.

The Navy has a real wide throat angle as does my Dread but the Dread has a very long shank and the Navys shank is short. The Dread is much lighter of course and therein probably lies the reason for very different shank lengths. I think of the Navy as a "buldozer" anchor and the dread in between. The one time I used the Dreadnought it set instantly. I took up the slack in the rode and "hey wer're not mov'in".

manyboats said:

Brian I had no idea the Navy anchors were considered Danforth types.

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Eric, I should have been more specific and said, "Pivoting fluke anchor type."

Apologies,
Brian

After Christmas, were going pick up one of these mantus anchors, currently we have a 105# CQR. Or should I hold off and spend a little more for an ronca?

N4712 said:

After Christmas, were going pick up one of these mantus anchors, currently we have a 105# CQR. Or should I hold off and spend a little more for an ronca?

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We have 30kg Manson Supreme on our 52' boat, with 350' of chain. I think the CQR 1905 might be a bit overkill- I think the Rocna or Manson 30kg should be more than adequate.

I don't know much about the Mantus, but I am a bit leery of an anchor that bolts together.

Pau Hana said:

We have 30kg Manson Supreme on our 52' boat, with 350' of chain. I think the CQR 1905 might be a bit overkill- I think the Rocna or Manson 30kg should be more than adequate. I don't know much about the Mantus, but I am a bit leery of an anchor that bolts together.

Click to expand...

Whats your displacement? Ours is 85,000. I was thinking of the Ronca 88lb, it's $100 more but probably go with it.

N4712 said:

Whats your displacement? Ours is 85,000. I was thinking of the Ronca 88lb, it's $100 more but probably go with it.

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Displacement is just about 80,000. We've anchored with the Manson all over Puget Sound at scopes from 3-1 to 7-1, and we've never dragged or had the anchor reset.

Pau Hana said:

Displacement is just about 80,000. We've anchored with the Manson all over Puget Sound at scopes from 3-1 to 7-1, and we've never dragged or had the anchor reset.

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Oh ok, I'll take a look at them. What's the bottom like where you usually anchor in the PNW? ( east coaster over here )

The bottom is good sticky mud.

48' Kadey Krogen 58,000 displacement with 112lb Rocna. I think the chain would break before the anchor would let go or drag. I would not want to be in the weather that would pull it loose. If you want to sleep at night get a Rocna one size larger than recommended.

rpeterson said:

48' Kadey Krogen 58,000 displacement with 112lb Rocna. I think the chain would break before the anchor would let go or drag. I would not want to be in the weather that would pull it loose. If you want to sleep at night get a Rocna one size larger than recommended.

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Yeah, we're going go with an 88lb ronca and keep the CQR as a backup.

Here's one of the most comprehensive anchor tests I've read. It was before the Mantis was but it covers the Rocna, Supreme and most everything else. The decision making elements are in the text .. not particularly in the graphs.

On an objective anchor test you wouldn't expect to find advertisement for one product w/o any comparable copy for the others. I think that's very bad journalism but the test seems to be one of the best out there. But I rode out two 50 knot gales with the lowest performing anchor in this test.

Pau Hana wrote "I am a bit leery of an anchor that bolts together" ...
I'm not. Just use a thread locker. Ever rode a motorcycle, flew an airplane or driv'in a car. Your life is dependent on lots of bolts. Not foolproof I'll admit but lots of other things happens to other anchors that have no bolts.

Good move. Rocna is a great anchor

N4712 said:

Whats your displacement? Ours is 85,000. I was thinking of the Ronca 88lb, it's $100 more but probably go with it.

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My guess is the 105# CQR will be superior to the 88# Rocna you plan on buying. Weight is your best friend. Be sure your connectors are WLL rated for more than the chain. Your blue water cruising intentions will need a lot more weight than the charts indicate, probably two sizes more, making the 88# Rocna too small IMHO. My next anchor will be 45 kg, and this for a vessel 25,000 lbs less than yours.

>Breaking one out, lifting and carrying a hundred pounder is also considerable strain on cruiser pulpits.<

Time to find and shoot the designer and fellow that built it undersized, and called the boat a cruiser..

The weight of the boat only counts in a heavy surge that is strong enough to make a chain rode bar tight and give the anchor a shock load.

A rode rider , or switching to a proper sized nylon rode will stop the shock hammering.

For boats that dance from side to side pulling up short on each tack, only a second anchor will stop the veering , and reduce the loads.

As long as the ground tackle can be retrieved in a normal manner, too heavy does not exist.

My only hope is the watch fob folks with a sales brochure that sez >use our 20lb miracle anchor for your Roomaran Maru , 20 ft wide 35 ft tall,< are DOWNWIND every night from my spot.

And the wind doesnt shift!

Tap into the Norhavn owners site. You will find a detailed anchor discussion by very experienced 47 owners.

rpeterson said:

Good move. Rocna is a great anchor

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Indeed it is but if you read the text carefully you'll see that it falls short on short scope performance. The Supreme and some others do not.

MyHarly we have hundreds of "very experienced" owners and if you were to read our archives you may learn a bit about anchors.

Where you really learn about anchors is out using them....

psneeld said:

Where you really learn about anchors is out using them....

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Amen!

In anchors bigger is always better. On a true blue water boat your anchor is a huge part of your insurance policy... and on a cruising boat all chain is the only way to go.. the rode takes a beating and only chain will last.

HOLLYWOOD

N4712 said:

After Christmas, were going pick up one of these mantus anchors, currently we have a 105# CQR. Or should I hold off and spend a little more for an ronca?

Click to expand...

I'd be leery of the Mantus for two reasons. First, the shank has a great deal less metal in it than its competitors and is made out of A36 steel, which is up to 3 times weaker than its competitors. Add those together and you have a shank that is likely to let you down. True, Mantus guarantees their shank, but that will be small comfort depending on where and when it bends.

Second, on another thread, the manufacturer did little to gain trust. Regarding the weak shank of their product, they first said they had replaced it with A514 grade steel, then backed off and said they were going to, then when some people's eyes began to get squinty said they already would have made the change if posters on that thread left them alone and stopped badgering them with questions.

The capper was posting a table of engineering calculations meant to show their shank was just fine for the purpose when compared to other's product that was bogus on its face. Rather than answering any questions on how they came up with these numbers, they simply removed the table and pretended it had never been posted. Further, when questions continued they didn't want to answer, they apparently simply asked mods to close the thread as well as subsequent attempts to reopen similar threads. All in all, not very confidence inspiring.

That said, it may be a fine anchor if the limitations of a hoop style hook don't worry you, but I would wait until, or if, they follow through with new metal for the shank. Even then, it will be weaker than the Manson.

All I know is from experience. I have anther KK owner swear by a Rocna. Another KK owner with a 52' swear by a Rocna so I bought one and also could not be happier. End of story. My experience tells me I bought the right anchor. It works long or short Rode.

Where you really learn about anchors is out using them....

Being towed off the beach as a Learning Experience?

The midnight dance with fenders . a Learning Experience.

Too easy to just remember that in some things ,

SIZE DOES MATTER!

MyHarley said:

Tap into the Norhavn owners site. You will find a detailed anchor discussion by very experienced 47 owners.

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OK MyHarley, so in a nutshell what says the site regarding the N47 users?

Hint - some of us may have been on the foredeck of a well traveled N47 or other Ns.

MyHarley said:

Tap into the Norhavn owners site. You will find a detailed anchor discussion by very experienced 47 owners.

Click to expand...

Yahoo groups annoy the crap out of me, wish they would just have a regular forum like TF or CF.