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Old 02-13-2011, 08:59 AM   #241
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Rocna owners, seems you need a better anchor

Eric's description of the benefits from using a wider shank/fluke angle in soft mud is accurate. This wider angle, which is 45 on the Fortress, will put the flukes in a position where they will provide much greater resistance in a soft mud bottom. I have attached a simple image which might be helpful in understanding this.

Unfortunately, in harder soils it will be difficult to set the anchor at the 45 angle, as it will have a challenge penetrating the sea bottom and it is likely to simply bounce along the harder bottom, so the anchor must be re-set back to the 32 angle to work properly there.

While the Fortress holds a US patent on the adjustable fluke angle anchor, it is certainly no secret among anchor design experts that a wider fluke angle offers far greater performance in soft mud.

I believe that guys like Robert Taylor of the US Navy, who wrote the anchor performance guides for the American Petroleum Institute, and companies like Vryhof in Holland have been designing anchors with this feature for decades in the offshore oil & gas industries.

If you guys really want to dig into this deeper, go to the Vryhof web site and download their "anchor manual." Then turn to page 32, which is interesting reading, and look at figure 2-10.

http://www.vryhof.com/

Regards,
Brian

Fortress Marine Anchors


-- Edited by Brian-Fortress on Sunday 13th of February 2011 10:01:27 AM
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Old 02-13-2011, 09:01 AM   #242
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Rocna owners, seems you need a better anchor

Marin,
True but the claw has a very high percentage of it's weight on it's fluke tips and it dosn't seem to do any good at all. It would appear that the sharpness of the fluke tips and the way it or they are presented to the sea bed has all to do w setting success.

-- Edited by nomadwilly on Sunday 13th of February 2011 03:18:57 PM
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Old 02-13-2011, 11:11 AM   #243
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RE: Rocna owners, seems you need a better anchor

Eric, in most tests and in my experience the Bruce always sets, and quickly.* Its problem is that its profile is such that it takes a heavy Bruce to sink in to the seabed and provide good holding power.* If buried, the amount of surface area exposed perpendicular to the rode is pretty significant.* The trick is getting it buried which didn't always happen for me with a 44# on a 36' sailboat.*

Most people are happy with their anchor.* Until they're not, and then its a bit late to fret over design details.
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Old 02-13-2011, 04:34 PM   #244
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RE: Rocna owners, seems you need a better anchor

Delfin,
The claw sets but it's doubtful if it sets w all 3 flukes frequently. I've seen several (at least) videos of claws dragging along but w one and sometimes w 2 flukes in the seabed but one (or even 2) still above the seabed. The claw has a feature that greatly aids setting and that is that it has a very high percentage of it's weight on it's flukes. One would think that should ensure it's setting but they don't often bury their flukes and their very blunt fluke tips probably has a lot to do w it.
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Old 02-14-2011, 04:47 PM   #245
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RE: Rocna owners, seems you need a better anchor

As a yachtsman I spend most of my time racing and dont often need to set an anchor. When I do, I like to be sure that the boat will stay put, especially if anchoring for the night.
After reading recent contributions to this and other forums, I wonder whether stories of actual experiences might carry more weight than all the confusing and oft-disputed load charts and diagrams with which we have been bombarded. Not to mention the negative tactics from some quarters. So far I have found a couple of such stories and am looking for more.
As a starter, try these links -

http://www.anchorright.com.au/news/?...n-Anchor-Right

http://www.anchorright.com.au/downloads/Tsunami.pdf

OK, by now you might guess that I use a SARCA anchor and have been quite satisfied with the results. The Excel is a very interesting design and if I ever decide to upgrade it would have to be up near the top of the list. To the guy who has hung his anchor up in the shed, why dont you call the manufacturer and ask for some advice? I am sure that you would get a positive outcome.
Tony.
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Old 05-31-2011, 08:14 PM   #246
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RE: Rocna owners, seems you need a better anchor

http://www.afloat.com.au/afloat-maga..._anchor_chains

Good article about several anchors..
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Old 05-31-2011, 11:06 PM   #247
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RE: Rocna owners, seems you need a better anchor

Meltemi, Hawkeeye,

The idea of the average boater doing testing has a lot of faults. Most boaters are a little biased to their own gear and methods and many are VERY biased. But the biggest problem is that most boaters don't anchor in conditions that actually test an anchor. I've only anchored in 50 knot winds once and that was with an anchor that anchor testers in a major anchor test could'nt get to set. As far as I could tell the boat didn't move in the 50 knot wind for one and a half days. I anchored in 30 knot winds w an undersized Danforth with very little chain. That one stayed put too but I've never seen a steel Danforth make anything but a very bad performance in any anchor test. I read anchor tests but have come to use them not as a guide but as an information center and pick out the objective information if there is any. Sometimes they comment on performance at various scopes and what anchors do better or worse. Relative information is often better than numerical information. There are some anchors that always do extremely well like Fortress and anchors that never are at the top regarding holding power like the SARCA. But the SARCA does everything well and sets extremely dependably. I'm going on a 3 week cruise in a week and I think the best anchor I could carry is the SARCA. Fortunately there are quite a number of anchors that are good solid performers. We've done the anchor dance 2 or 3 times before. Check out the archives.

PS,** I finally did try the XYZ Extreme. I anchored in the bay in 30' of water and started pulling on the rode at 1-1 scope. The anchor could be felt bouncing along the bottom. Better at 2-1 and setting and releasing several times at 3-1. All this was with no chain. At 4-1 the anchor stuck and made a very tight rode. Just a first time out of the barn report.

*

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Old 05-25-2015, 09:18 PM   #248
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We have dragged all over the shop using a Lewmar Delta, that was great fun. We once anchored in the main Brisbane river right next to the CBD using 4:1 scope, with the outgoing tide we nicely exited backwards dragging over not one but two cross river energy cables, so that was awesome. Another time (with the same anchor) we were waiting on the up river side of a bridge waiting for the tide to drop fully so we could go under said bridge and looked out the window 5 minutes after setting the anchor to see we were careening at around 4-5 knots directly towards a very large and scary concrete bridge pylon.

So were are currently using this anchor as a large paperweight, although its possible in a small blow the paper will fly away if history is anything to go by...

We wanted to get a Rocna but couldn't afford that rates they wanted, then a mate said he brought an anchor off this place just-anchors and has been really happy with it, we havent ordered ours yet as we are still onshore finishing our rebuild but given they look to be around 50%-70% cheaper than the Rocna we and happy to give it a try. If anyone else has had one of these anchors we would love to hear about it as they look to be the same as a Rocna from what we can see.
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Old 05-26-2015, 12:11 AM   #249
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Damien, to make this meaningful, what weight is the Delta, what weight is your boat and what kind of hull, is your rode all chain or combination chain/line? Don`t you get massive tide runs in the Brisbane river. I think the Lewmar Delta has a good following. Setting technique is important too, eg I like to drive my Super Sarca in using reverse.
Be wary of buying a no name anchor. Good makers put much effort into design and testing and customer service. CQR copies were often not the same as the originals. Low price is not always a good indicator. You might look at the site for the homegrown product, SARCA, Anchor Right Australia, for an example of a known product, but as you`ll see from this thread, there are many opinions of many people on many anchors. There is a current thread begun by ksanders on his new Sarca Excel,which is worth a look.
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Old 05-26-2015, 12:18 AM   #250
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No, it's not the same design as a Rocna. There are all sorts of differences, some subtle, others very obvious. Doesn't mean it's not a decent anchor, but if the seller is telling you it's exactly the same as a Rocna he's either lying to make a sale, he has no idea what he's talking about, or he's never seen a real Rocna.
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Old 05-26-2015, 04:27 AM   #251
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Anchor details

Hi all

No the seller has never compared it to a Rocna and has been fairly good to deal with so far. He seems to acknowledge the limitations of his anchors as such.

Re the Delta

The boat was a 3.5t 28ft yacht
Anchor was a 10kg Delta
Rode was all chain 8mm short link
Tide was about 2.5-3knots
Bottom was sticky black mud

We always set and back down of our anchors at around a 3:1 scope then let out more to suit our surroundings.

Normally I would have thought the above would be enough to set well. It did seem to hold for a good few hours, but it was overnight that we dragged, the thing that stopped us was we dragging right up to a mooring so I chucked a rope around it so I could get some sleep and deal with it in the morning
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Old 05-26-2015, 06:44 AM   #252
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Dame.in.Jesse, that anchor looks so much like a sort of mating union between Rocna and Manson Supreme it might just work ok, but I'm amazed they have got away without some patent stousches along the way, as it is certainly a knock-off of them.

I can however back what BruceK just posted re the Sarca, and in exactly this positions you mentioned, because we have anchored right there in the brissie river on numerous occasions with a 9 tonne Clipper 34 on a 22kg Super Sarca, and never dragged, as we frequently went up the river to those spots for the new Year's Eve fireworks. Might pay to take a look at Bruce's link.
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