KnoxAnchor - has anyone any experience of using one?

[NormanS]

The Knox anchor is very new. Arranite's report is the first independent evidence I have read.

I have a high degree of cynicism concerning manufacturers' tests. If nothing else manufacturers naturally pick a substrate where their anchor does best. I don't see anything wrong with this, but I believe we should treat the results as more along the lines of marketing material rather than a true representation of how the anchor will perform in the real world.

If the claims by Knox Anchors are true it would be great. They show the anchor has 60% greater holding than the other top performers. The Spade and Rocna, closely followed by the Manson Supreme with the Danforth also doing well. I remain sceptical, but it would be great to see this anchor in action.

Wow! I don't know how I've survived for so long. My main anchor for the past eight years has been a Bruce, which according to that table is like a chocolate tea pot.
Even worse, for the previous 30+ years, my main anchor was a fabricated plough.

Anchoring >100 times per year on the West Coast of Scotland.

 

[J Neeves]

Here is an additional comment received today:

Author: Don Joyce
Comment:
To be fair, we were on short scope around 4:1 to 5:1 due to limited swinging room. We usually have what late comers to an anchorage call "excessive" scope of at least 10:1. The excessive scope held us firm on the Rocna in Maine during Irene when several of the complainers around us dragged.

I did write to Rocna to suggest they need more weight in the tip. I will add some weight myself when we get the anchor galvanized.

A response to this comment:

http://www.morganscloud.com/2011/11/23/rocna-versus-spade-anchors/

Author: John
Comment:
Hi Don,

Thanks very much for coming up with that vital information. We are hearing of an increasing, albeit still small, number of these incidences with the Rocna. It's particularly disturbing that this happened with such a large anchor.

I think this danger is something that every Rocna owner needs to be aware of, so thanks again.

See all comments on this post here:
http://www.morganscloud.com/2011/11/23/rocna-versus-spade-anchors/#comments

It is interesting that there have been many tests conducted and some users reports all underlining the problems of concave, roll bar anchors clogging. Most of these reports have been rejected by the sycophants. In addition we also have the Fortress results raising the spectre that some roll bar anchors may not self right in soft seabeds (though this might be common to other anchors as well).

Possibly some of these anchors should be sold with safety warning labels, 'do not use in mud or soft seabeds'.

But I agree with John from Morgan's Cloud - a bit of cold, honest information would be invaluable.

Jonathan

 

[Bloomy]

1. Storyline Writes
Registered User Location : Liverpool - boat Ardfern
There is a comment on the Knox site in the Anchoring Technique page.

The professor says the following :

A good modern anchor should start embedment immediately and develop its maximum hold or UHC after it has ploughed a 5 to 10 metres. By that time it should have rotated to a vertical position, and should be completely buried.

On face value this seems to say that a NG anchor will continue to move after the initial set. This is not something I have experienced with either of the two techniques we use now with our Rocna. If the bottom is sand then we find no finesse is needed; drop anchor, drop back, dig in (fast or slow makes no difference, the anchor buries immediately). Things are different in a couple of soft muddy anchorages we use and I now use quite a few bursts of reverse to slowly dig the anchor in. You get a feel for what the anchor is doing and typically it will set in just a few metres but with each ever increasing amount of reverse it will move backwards but never more than a very few metres.

Am I reading the professor correctly, is he saying that to achieve a full set the anchor will move back 5 - 10m ? My feeling is that the only way our Rocna could move that far (once set) is for it to break out.

He also says the anchor ends up in a vertical position - can that be right ?

John Writes

Well story line, it depends on who you believe, John Knox is clearly speaking of a anchor pull test, pulled way beyond any load you will experience from your boat when simply setting your anchor, he is quoting max load before break out or drag distance, this test is also governed by the type of substrate the anchors are being tested in, these anchor sizes are normally around 12 to 15 kilo range, anything larger when testing is too difficult to handle and would require serious winching equipment as they will not travel any further than a couple of feet.

So Yes in this instant bigger is better, if you take an enormous anchor like Noelexs on such a small boat it is any no wonder in sand and light weed his anchor travels very little distance before holding, minimum backing up distance, shuffling around, listing as he calls it and staying anchored in a change of tide or wind shift is always going to be the norm with such a large anchor on such a small boat
I do have a problem when some say they are skeptical of a anchor designers test, especially well identified we all know who John Knox is, so when publically throwing down lose comments one should check themselves, in this instant “tell us who you are” what credentials you have other than a Moderator of another forum, photographing anchors , commenting and displaying a mermaid.

Obviously we have all been treated to some eye opening problems when setting anchors,” for this I am great full “ commenting on anchor designs and how they work, you are well of the mark.
I think John Knox is a very intelligent man with anchor design experience few have, I would never insult his intelligence by saying his testing is to be treated with skepticism.

When it comes to skepticism Noelex just has to cop it on the chin for his comments Re John Knox, the anchor on Noelexs boat is huge, given to him, five months of trialing, defending, one has to become a bit partial to this anchor, certainly buds will start to flower in the relationship with the supplier, Just saying.

If you go through any anchor forum, you will find there are now many, many concave anchor roll bar designs dragging,” mainly related to mud” one design as mentioned in this thread is becoming common place and stands out in particular, it has made headlines in the past for all the wrong reasons, looks like it will do it again, if we are talking real world tests over time then this is as real as it gets, even though the bigger is better slogan was mysteriously born shortly after concave roll bar designs hit the market, it has not solved this problem.

Who am I, I am a supplier and advisor for varying sections of the Marine industry, I am involved with ports, fisheries, heavy work barges and delivery of goods to oil Riggs in Bass Strait.

Yours truly John.

 

[Pasarell]

I'm nervous about resurrecting an anchor thread....
This is old thread islargely about the Knox anchor which I am close to making a decision to buy. Does anyone have more comments to make about the Knox after a few years more experience.
My boat is a Moody 44 that will be in the Med for the next couple of years at least. I have a Fortress FX23 as well. The Knox I am considering is 27kg and, apart from being a NG anchor, I am tending towards it rather than the other obvious candidates because it is British made. It will replace a 25kg Delta.

Thanks in advance for comments and I hope this doesn't degenerate as some anchor threads have in the past.

 

[Arcady]

I'm nervous about resurrecting an anchor thread....
This is old thread islargely about the Knox anchor which I am close to making a decision to buy. Does anyone have more comments to make about the Knox after a few years more experience.
My boat is a Moody 44 that will be in the Med for the next couple of years at least. I have a Fortress FX23 as well. The Knox I am considering is 27kg and, apart from being a NG anchor, I am tending towards it rather than the other obvious candidates because it is British made. It will replace a 25kg Delta.

Thanks in advance for comments and I hope this doesn't degenerate as some anchor threads have in the past.

I will tell you in a few weeks! I have just ordered the 13 kg version for my 33’ boat. I’m looking forward to trying it out (it will replace a 15 kg Bruce, which I really don’t like).

 

[sarabande]

I've had a 9Kg Knox for two years on a 6 ton sail boat. A bit undersized, but it does its job routinely and with no fuss. The only time I had problems setting was on a bank of large cobbles (about 8 to 10 inches diameter) Once in smaller stones, it was fine and dandy.

You should be OK with two different styles of NG anchors, though someone will come along and suggest that all you need for the Med is a large rock with a hole in it. Or a fisherman. Or a Bugelspadexcel in platinum-coated molybdenum on a 2mm piano wire.

The company is now owned by a regular poster here, and advice is quick, clear and technically excellent. Well done for thinking to buy British, BTW.

 

[Neeves]

No reservations on buying a Knox, excellent product, one of the strongest anchor available (or certainly looks that way - strongest shank I know of, good welding, good galvanising). The shackle slot is a bit tight - not much 'slack' (but maybe that has been altered). The slot is not a deal breaker. Sets quickly, holds exceptionally. Good combination with a Fortress.

I don't think you need to buy it because its British, or specifically Scots - you can comfortably buy it because its at least equal to or better than the next 'best in class' - being British will just give you that extra comfortable glow which will be an asset when you are in your berth and those cold winds are howling.

I've been testing the 13kg model - I cannot use it as THE primary - it will not fit and I'm not prepared to spend thousands, as I'm a Scot, to modify the bow roller.

Jonathan

 

[awol]

I've been testing the 13kg model - I cannot use it as THE primary - it will not fit and I'm not prepared to spend thousands, as I'm a Scot, to modify the bow roller.

Jonathan

You could always try asking Geoff to modify the roll bar to fit your boat. The Prof (John Knox, the originator, not the Calvinistic preacher) did one for me with a U-shaped mod to fit round the forestay. I'm not saying he will but if you don't ask .........

 

[stevie69p]

I have the 13Kg on an LM27 (about 4.5 tonnes loaded), which is over sized but my choice to have beefy ground tackle as when I'm sailing, I anchor a lot. It replaced a 10Kg Delta which came with the boat, that I wasn't super happy with after dragging it around an anchorage one breezy afternoon in the rain trying to get it to set.

So far... absolutely zero issues with the Knox. It has set first time, every time, in various sea beds from sand, mud to gravel and never dragged. I also picked it because it is made in Scotland, but don't let that sway you hehe...

I had to modify the pulpit bi-colour nav light fixing (upwards by about 6 inches and out by about 3) in order to be able to clear the roll bar and have the anchor stowed on the bow roller. This will of course be boat specific.

In conclusion, I would have no hesitation in recommending the Knox.

 

[Pasarell]

Thanks very much all of you for the positive comments. And for keeping it light hearted on an anchor thread.... I think I'm convinced to take the plunge into the world of NG anchors

 

[Neeves]

Pasarell,

I now note you are in Greece - how do you get an anchor from Scotland to you?

You will not regret the decision to change to an NG - good luck.

Jonathan

 

[Pasarell]

Jonathan
Geoff at Knox has quoted me a price including delivery to Greece of £48. That was an important factor as I expected it would be a lot more expensive.
Thanks for earlier advice
Peter

 

[Neeves]

Thanks Peter,

I think that freight charge will be of interest to many - as I'm sure they are put off as they might guess (as I would have done) that it would be much more expensive.

I'd suggest you ask Geoff to supply you a shackle (I'd also buy a spare - shackles are usually not expensive) to match the anchor and chain - it might be easier to get it via him than search Greek chandlers. I know Geoff has some shackles and I know he has had them tested to destruction - so he knows if they can be trusted. He will, obviously need your chain size (and if you have anything sufficiently accurate - measure the hole in the link - they do vary slightly). Obviously if you can buy Crosby shackles easily that is another option - but somehow I suspect it might be difficult (but then I would have been wrong on freight charges!) Remember you need to mouse the shackle (again get Geoff to include if you do not have any) or use Loctite.

Hopefully Geoff is supplying all of this as a package - as I'm sure that is his intention - as its so much simpler for the owner.

Jonathan

 

[Neeves]

Peter,

You need to peak to Geoff - the Knox and anchor I have has a slot, Vyv Cox has a hole. It looks as if, for the shank with a hole, you might need to ask Geoff for 2 shackles and spares. Why spares, I'm fairly careful (but dropped a shackle pin overboard!)

It look as if you will need to use 2 shackles.

Check this thread

http://www.ybw.com/forums/showthread.php?501449-Connecting-anchor-to-chain

specifically the last few posts.

Jonathan

 

[vyv_cox]

It's a bit early for me to give a definitive critique of the Knox as we have only used it a dozen or so times. Setting has not been ideal but we have deliberately chosen some difficult anchorages with a fair bit of weed and one possibly with rock beneath shallow sand. Once set the anchor has been good and we have slept on it around 8 times, one in a fair bit of wind and chop. I am wondering if it maybe needs a rather greater scope than we have been used to with the Rocna but this is by no means confirmed.

We are using it with a Marine Town double jointed swivel, which has given no problems.

 

[Neeves]

On reflection - A few anchor are, were, made with a hole and not a slot, CQR being the best example, Manson's Ray and the Guardian. It is intended they use a shackle with the pin in the hole - and genuine CQRs came with the shackle welded in.

In this case, Knox, I would use the biggest 'D' hackle I could find whose pin would fit the slot and then use a bow shackle, bow through the 'D' to attach chain to shackle/anchor. The big 'D' shackle will withstand side loads, particularly if you use a G209A from Crosby, which come in Bow or 'D' shapes. You will get the articulation from the bow shackle.

For those advocates of stainless. The best you can buy are Duplex, as GHA suggested, Petersen or Cromox. These, the best, are Grade 50 (or 60?) don't recall - Crosby shackles are paired with lifting G80 component and chain, so significantly better than the best of stainless - most stainless might be G30 or 40 (or worse). Un-rated Stainless would not pass Proof Test, an ability to remove the pin when tested to 1.5 or 2 times WLL - and un-rated stainless are very unlikely to be individually tested - if they are actually tested at all.

I did test alan keyed, 316 stainlesss, bow shackles from Tecni - unbranded, specification of UTS 6t. it was lovely, all shiny and smart. They failed at 4.5t - the shackle pin deformed so much it pulled out of the eye of the body of the shackle - but it did not snap. At 4.5t the shackle was sized for a G30 chain, so the shackle a bit stronger. I pointed the discrepancy out to Tecni - they did not comment. I would not buy unbranded shackles. I don't mind shackles being weak, if that is what the specification is (most are not sold to any specification) - I do mind when they specify strength and the shackle does not meet that strength - it implies to me they, the manufacturer and the distributor, simply do not test! Here when a batch of shackle arrives, usually from China, if 2 shackles fail (I think from 5 randomly selected) they test another set of samples - if these fail the complete shipment is rejected (and sent back to China). It is then meant to be destroyed??

Check also safety factors - Crosby G209A shackle are made to a 4.5:1 safety factor, their 209 shackles (roughly half the strength of the 209A hackles) made to a 6:1 safety factor - from memory some Harken shackles are made to a 2:1 safety factor (different applications). For reference metric chain is a 4:1 safety factor.

Jonathan

 

[Humblebee]

I bought a 13kg Knox last year and have been happy with it. Also very happy with the customer service I received from the company, including delivering the anchor free as he was going near my house anyway.
Once the Knox is set it's set and can need a fair bit of pulling out. I usually pull in as much slack as I can by hand then cleat the chain off and use the engine to lift the anchor from the sea bed.
Only once have I been unable to get it to set and that was at Canna. The anchorage there seems to be getting weedier and I know others too have had problems getting their anchors to bite so I wouldn't see this as a specific criticism of the Knox.
The only (slight) issue I have is storing it on deck and this seems to be a common problem with new generation anchors. Perhaps I just need to spend more time looking/thinking and experimenting!

 

[pagoda]

We now have Knox (13) . Previous boat had a Manson which I liked. They are pretty similar and the local manufacture was an attractive aside. So far it has behaved well. It replaced a Bruce lookalike on our newer boat- which was fine in mud and sand but not hard sand or any weed. I anticipate the Knox being as good as the Manson for re-setting on tide changes.
Slightly different stowage - but perfectly workable.
I anticipate a lot of anchoring this summer