JKay
New member
looks like a "Rochna"copy /forums/images/graemlins/laugh.gif
Rocna or Manson Supreme??
- Thread starter Richard10002
- Start date
AncoraLatina
New member
[ QUOTE ]
looks like a "Rochna"copy /forums/images/graemlins/laugh.gif
[/ QUOTE ]
Oh Nooooooooooooooooo !!!..
Yes it looks like an anchor... but it’s different from the Rochna!..
- 1° No BSH (big stupid hoop)
- 2° More weight on the tip
- 3° More blade surface area (about 25% more)
- 4° Much cheaper
- 5° I suppose your comment has been made on purpose to see what will be my reaction?? /forums/images/graemlins/ooo.gif
[ QUOTE ]
<span style="color:blue"> steveallan I would be surprised if there was any significant difference between the Manson and the Rocna</span>
[/ QUOTE ]
Yes they are very similar, but one is better manufactured... at least the New Zealand manufactured one!
We don’t know yet about the quality of manufacturing of the one made in China?
João
looks like a "Rochna"copy /forums/images/graemlins/laugh.gif
[/ QUOTE ]
Oh Nooooooooooooooooo !!!..
Yes it looks like an anchor... but it’s different from the Rochna!..
- 1° No BSH (big stupid hoop)
- 2° More weight on the tip
- 3° More blade surface area (about 25% more)
- 4° Much cheaper
- 5° I suppose your comment has been made on purpose to see what will be my reaction?? /forums/images/graemlins/ooo.gif
[ QUOTE ]
<span style="color:blue"> steveallan I would be surprised if there was any significant difference between the Manson and the Rocna</span>
[/ QUOTE ]
Yes they are very similar, but one is better manufactured... at least the New Zealand manufactured one!
We don’t know yet about the quality of manufacturing of the one made in China?
João
noelex
Well-known member
I think they are both excellent anchors, but there is no question go for the Rocna. There is a lot of debate if the Manson has got as good holding power and quality of construction as Rocna. In the USA the Rocna sells for considerably more than the Manson and many contend that its worth the premium.
When they are the same price the decision should be easy even if you have to wait slightly longer to get the Rocna.
When they are the same price the decision should be easy even if you have to wait slightly longer to get the Rocna.
A
Anonymous
Guest
Who actually makes the Rocna, now? Is it made in Rocna's own, owned factory or is it subcontracted? Are they actually made in NZ? There was an issue about this a couple of years ago, I recall. Does anyone know the spec for the galvanising on the Rocna and Manson?
As for Chinese-made anchors....some of the world's finest production comes from China!
As for Chinese-made anchors....some of the world's finest production comes from China!
vyv_cox
Well-known member
Here's how to avoid lateral loads and wedged shackles with a plate steel anchor shank. Two chain links would also be OK. In the photo the three links are 10 mm, the main chain 8 mm. I believe this to be just about the strongest and most versatile arrangement available.
Don't use a galvanised shackle, use a Wichard 17/4 PH countersunk. In the YM destructive tests the stainless shackles were almost all stronger than the galvanised ones. Use Studlock with the countersunk pins to prevent unscrewing.
Don't use a galvanised shackle, use a Wichard 17/4 PH countersunk. In the YM destructive tests the stainless shackles were almost all stronger than the galvanised ones. Use Studlock with the countersunk pins to prevent unscrewing.
A
Anonymous
Guest
The Kong two-part connector (you tested one for your report, I believe) actually has a lateral load specified. The one I bought has a lateral rating of some 1.5 tonnes. When you do the maths, the turning moment of 1.5 tonnes at the extreme end of the shank would bend the entire shank round on itself like a corkscrew. To put it another way, if the anchor was trapped in such a way that it could not turn then whether you have chain links or the Kong connector, you are going to relieve the moment by bending the shank itself.
That, for me, was one of the biggest selling features of the Kong -- plus the fact that when you look at it on the desk it is clearly a beautifully made and engineered product. Crevice corrosion is the risk for stainless, of course, but I check mine.
That, for me, was one of the biggest selling features of the Kong -- plus the fact that when you look at it on the desk it is clearly a beautifully made and engineered product. Crevice corrosion is the risk for stainless, of course, but I check mine.
DaveS
Well-known member
I'm not so sure about that. I have a Kong anchor connector on my 16kg Delta and, following a fairly severe test which I wrote up here: http://www.yotblog.com/DaveS/785/ (2-4/7/05), its jaws were splayed by about 1mm. I put this down to leverage from the well buried, and nearly immobile, anchor shank, possibly during one of the more dramatic wind shifts. I'm still using it, having persuaded myself that it is (just) still OK and hasn't lost strength, but would like to adopt Vyv's idea of inserting a couple of chain links to prevent a recurrance if I can re-arrange the foredeck to allow it. The anchor shank shows no distortion.
A
Anonymous
Guest
Is yours the two-part Kong, marked with a lateral force rating? When I fitted mine I read Vyv's report and we discussed the subject in this forum at some length. I dug out some stress figures for steel, and measured up my Delta. Even if the Delta had had a Young's Modulus at the top of the likely range we would have seen a bending moment way beyond the probable elastic limit before the lateral force reached even half the rated load.
On the other hand, your information is from practical experience, not theory. Though I feel very uneasy when what should be perfectly sound theory lets us down badly!
I wonder whether your Kong is of a different design to mine, and not made for high lateral forces? Or maybe Kong's product doesn't do what they claim....but then again, the general engineering of it inspires confidence, so that would surprise me.
I'd like to get to the bottom of it. After all, if the Kong is safe then it is an ideal solution -- the extra links and shackle are not ideal. Furthermore, unless the shackle fits the slot in the shank perfectly then the sharp edge of the slot forms a cutting edge for the shackle pin. The stresses caused by that could reduce the load resistance of the shackle by an order of magnitude. Even the best shackles struggle to match the stated working load of the Kong leaving aside the issue of stress from the sharp edge.
When I shackle on an anchor I use a massive shackle with a pin diameter almost equal to the width of the slot, for that reason, but it would not be convenient to keep that on the foredeck, on the bow roller -- Hence the Kong.
On the other hand, your information is from practical experience, not theory. Though I feel very uneasy when what should be perfectly sound theory lets us down badly!
I wonder whether your Kong is of a different design to mine, and not made for high lateral forces? Or maybe Kong's product doesn't do what they claim....but then again, the general engineering of it inspires confidence, so that would surprise me.
I'd like to get to the bottom of it. After all, if the Kong is safe then it is an ideal solution -- the extra links and shackle are not ideal. Furthermore, unless the shackle fits the slot in the shank perfectly then the sharp edge of the slot forms a cutting edge for the shackle pin. The stresses caused by that could reduce the load resistance of the shackle by an order of magnitude. Even the best shackles struggle to match the stated working load of the Kong leaving aside the issue of stress from the sharp edge.
When I shackle on an anchor I use a massive shackle with a pin diameter almost equal to the width of the slot, for that reason, but it would not be convenient to keep that on the foredeck, on the bow roller -- Hence the Kong.
noelex
Well-known member
[ QUOTE ]
Does anyone know the spec for the galvanising on the Rocna and Manson?
[/ QUOTE ]
I took these photos recently of a rusty Manson Supreme with a bent tip.
Does anyone know the spec for the galvanising on the Rocna and Manson?
[/ QUOTE ]
I took these photos recently of a rusty Manson Supreme with a bent tip.
vyv_cox
Well-known member
My main purpose in inserting the chain links was to avoid this situation, which happened to me on several occasions.
YM printed an article about it in August 2008.
In this situation a lateral load can be applied to the connector while the anchor is in its normal attitude, and high loading could be present in the warp.
For me this is the strongest argument against the long slot in the Manson anchor. I don't understand why any manufacturer uses a slot. I see no benefits for it (except the Manson argument) and a strong disadvantage.
Any anchor manufacturers care to comment?
YM printed an article about it in August 2008.
In this situation a lateral load can be applied to the connector while the anchor is in its normal attitude, and high loading could be present in the warp.
For me this is the strongest argument against the long slot in the Manson anchor. I don't understand why any manufacturer uses a slot. I see no benefits for it (except the Manson argument) and a strong disadvantage.
Any anchor manufacturers care to comment?
NormanS
Well-known member
I would have thought that the slot was to allow a decent sized shackle to be used to attach the chain to the anchor. Otherwise, unless the chain has an enlarged end link, you would have to use two shackles.
noelex
Well-known member
The Manson supreme has 2 positions the chain can be attaced. The idea of the long slot is that if the anchor is caught the shackle will slide forward and pull from the head of the anchor. The drawback is if the wind shifts the same thing will happen and the anchor has no chance for resetting. For this reason the slot can only be used if a constant visual watch is maintained, say when fishing for a few hours. It also weakens the shank which is an area that the manufactures try to make as thin, but as strong as possible. (Both Rocna and Manson use high tensile steels for the shank)
Chris_Robb
Well-known member
Vyv - we seem to be comparing anchors against just price. I know that some anchors - possibly the bugles, are made locally, but out of what quality steel? If you look at the Manson website, they specify the specification of the steel used - high tensile Bisalloy80 steel - which I presume is a very high spec.
Surely what they are made of is essential when it comes to survival situation - or are they totally over engineered?
Also as these are welded products, the quality of the welding is vital as well.
Surely what they are made of is essential when it comes to survival situation - or are they totally over engineered?
Also as these are welded products, the quality of the welding is vital as well.
A
Anonymous
Guest
I've put a ss bolt through the slot to stop that happening. So my Kong always presents flat-on to the slot. I have a Delta....to stop a shackle pin from presenting against a cutting edge of the slot you need a shackle that is vastly over-sized for the job. Could be done, though, and is a valid solution -- I use it on my second anchor when I need to deploy it. Slots are supposed to make it easier to get the anchor up if it is stuck...by pulling back into the slot you effectively have a trip line. I'm not sure how you would know which direction to pull in after a few days at anchor!!?
AncoraLatina
New member
[ QUOTE ]
Any anchor manufacturers care to comment?
[/ QUOTE ]
Yes, I do /forums/images/graemlins/smile.gif although it’s somewhat difficult to criticize the competition /forums/images/graemlins/grin.gif
1° First about anchor connectors: I fully support the comments of vyv Cox: Never use a swivel connector directly on the shank of the anchor:
- they don’t turn under load
- they are not designed to support any lateral load
2° - I’m completely AGAINST the slot on the shank – for me it’s only a « marketing » advantage.
- It weakens the shank
- If your anchor is wedged somewhere, it will not work
- But if there is a shift of wind or current, then it will ALWAYS work and pull your anchor out!
- This slot can be useful only for fishermen who are often temporarily anchoring in rocky areas (and stay aboard to check the mooring)
3° - About the interesting Noelex’s photos: make a very simple experience:
- take a glass (bier?) put a rectangular sheet of paper on the top of it and then put a money coin on it, the weight of the coin will bend the paper and the coin will fall down into the glass.
- Now, take the same piece of paper, fold it in the middle once or make several « accordion » folds, put it back on the glass and put the money coin again on it... It will not fall down!
- This is a very well known principle, always used in cars panels!
- Now look at the shape of the Supreme blade, it is made of a rolled sheet of metal. To cylindrically curve a sheet of metal is a very easy manufacturing process made with a very cheap machinery.
- At the tip level, the sheet of metal is nearly flat and will easily bend!
- If you look now at the tip of the Rocna, the tip is folded in the middle!
Now make your own mind about the comparative solidity of both! /forums/images/graemlins/confused.gif
João
Any anchor manufacturers care to comment?
[/ QUOTE ]
Yes, I do /forums/images/graemlins/smile.gif although it’s somewhat difficult to criticize the competition /forums/images/graemlins/grin.gif
1° First about anchor connectors: I fully support the comments of vyv Cox: Never use a swivel connector directly on the shank of the anchor:
- they don’t turn under load
- they are not designed to support any lateral load
2° - I’m completely AGAINST the slot on the shank – for me it’s only a « marketing » advantage.
- It weakens the shank
- If your anchor is wedged somewhere, it will not work
- But if there is a shift of wind or current, then it will ALWAYS work and pull your anchor out!
- This slot can be useful only for fishermen who are often temporarily anchoring in rocky areas (and stay aboard to check the mooring)
3° - About the interesting Noelex’s photos: make a very simple experience:
- take a glass (bier?) put a rectangular sheet of paper on the top of it and then put a money coin on it, the weight of the coin will bend the paper and the coin will fall down into the glass.
- Now, take the same piece of paper, fold it in the middle once or make several « accordion » folds, put it back on the glass and put the money coin again on it... It will not fall down!
- This is a very well known principle, always used in cars panels!
- Now look at the shape of the Supreme blade, it is made of a rolled sheet of metal. To cylindrically curve a sheet of metal is a very easy manufacturing process made with a very cheap machinery.
- At the tip level, the sheet of metal is nearly flat and will easily bend!
- If you look now at the tip of the Rocna, the tip is folded in the middle!
Now make your own mind about the comparative solidity of both! /forums/images/graemlins/confused.gif
João
A
Anonymous
Guest
[ QUOTE ]
Never use a swivel connector directly on the shank of the anchor:
- they don’t turn under load
- they are not designed to support any lateral load
[/ QUOTE ]
Not true. The Kong connectors are specified to take a defined lateral load -- this is clearly marked on the data sheet. In my case, for my Kong, the lateral load rating of 1.5 tonnes is actually greater than the SWL of a steel shackle that you would intuitively choose to connect the anchor.
Since you are an anchor mfr/rep I strongly urge you to check this point with Kong. The data are on their website, and they speak English.
Never use a swivel connector directly on the shank of the anchor:
- they don’t turn under load
- they are not designed to support any lateral load
[/ QUOTE ]
Not true. The Kong connectors are specified to take a defined lateral load -- this is clearly marked on the data sheet. In my case, for my Kong, the lateral load rating of 1.5 tonnes is actually greater than the SWL of a steel shackle that you would intuitively choose to connect the anchor.
Since you are an anchor mfr/rep I strongly urge you to check this point with Kong. The data are on their website, and they speak English.
A
Anonymous
Guest
[ QUOTE ]
Now make your own mind about the comparative solidity of both!
[/ QUOTE ]A picture of a bent anchor speaks for itself. Might have been trapped in rocks/coral tho' and no anchor could survive that.
Now make your own mind about the comparative solidity of both!
[/ QUOTE ]A picture of a bent anchor speaks for itself. Might have been trapped in rocks/coral tho' and no anchor could survive that.
ditchcrawler
Well-known member
When I bought my Rocna the makers advice was not to use a connector(swivel or other) but a plain shackle.I bought a tested shackle from Eye Co(who are local) & it works a treat.The anchor turns the right way up on entering the stemhead without problem.
Jonny_H
New member
FYI - Rocna's are made in NZ or under license in America. We got ours direct from NZ - the UK agent (in Ireland) gets them shipped from NZ. We have a 20kg one - think it is the best thing we've bought. No point saving money on an anchor - you'll be glad you spent the extra at 4am in a gale! They are more expensive, but the cost is quickly recoupped when avoiding marinas (we haven't used anything but our anchor since we left the Canaries).
As for Manson vs Rocna - there used to be a page on Rocna's website stating why there's was better built etc - its since been removed for (I believe) legal reasons - we went for the Rocna but they are very simalar from what I understand.
Jonny
As for Manson vs Rocna - there used to be a page on Rocna's website stating why there's was better built etc - its since been removed for (I believe) legal reasons - we went for the Rocna but they are very simalar from what I understand.
Jonny
A
Anonymous
Guest
Yes, they have a good following but then you'll find a strong following here for everything from Admiralty anchors to mud anchors! /forums/images/graemlins/wink.gif However, I have noted that the posters who have given me consistently good advice over the years also recommend Rocna, so I am not a Rocna-knocker. Wouldn't fit my boat, though, without very serious modification as the huge roll-bar would have fouled the pulpit and I would have needed to have added nearly a metre to the boat's LOA or re-constructed the pulpit. Neither were acceptable. So beware, folks, the Rocna is big which might be no problem on your yacht....do check it out though as it is hard to return an unwanted anchor /forums/images/graemlins/shocked.gif
When you say that there are Rocnas being made in 'America', do you mean the USA?
When you say that there are Rocnas being made in 'America', do you mean the USA?