Knox Anchor - Best Features of Two Designs or Not?

  • Thread starter Thread starter C08
  • Start date Start date
C

C08

Well-Known Member
Joined
8 Feb 2013
Messages
3,959
Visit site
I am drawn towards getting a Knox however the lack of independent test results and the unusual two pronged blade is making me hesitant. The anchors look very well made and heavily built with an impressive spec and it may be that the split blade will have the good bottom penetration of the Fortress/Danforth types but will have the good re-setting chacteristics of the other very similar NG anchors, so arguably the better features of two different but successful anchor designs-so best of both worlds or not. Any actual experiences of using a Knox?
 
I've got the 13kg model. I too have had no issues. it sets very quickly and holds tenaciously. It is excellent in sand and mud, thick mud. Its structurally very strong and made (shank) from the strongest steel used for anchors. It is well galvanised - by a company that knows the marine industry.

I'm less enamoured in weed, but most anchors have the same issues. The best anchors in weed are Spade and Excel - but thick weed will defeat most anchors.

The shackle slot is a bit small, I'd rather it was slightly bigger. I am concerned that the pockets in the fluke will hold mud - but if you are aware this might be a possibility and wash clean - there is no issue.

I've only 'tested' it - it will not fit on my bow roller (the roll bar gets in the way) and I'm not paying thousands, literally, to get it to fit (its constrained by a structural component).

I have yet to try it in stony, pebbly seabeds, we have none nearby. Again, so far I'd favour Spade or Excel - but maybe the Knox will also stand out in stony seabeds.

I would strongly recommend it.

Jonathan
 
Last edited:
I sleep better lying to my Knox than I did to my heavier CQR.
Full chat in astern and my 1GM10 could get the CQR to slowly plough through the bottom (it is a plough after all). With the Knox, Ladybird is brought up short as the chain goes taut then relaxes into its catenary when I back off the throttle.
 
Porthandbuoy said:
I sleep better lying to my Knox than I did to my heavier CQR.
Full chat in astern and my 1GM10 could get the CQR to slowly plough through the bottom (it is a plough after all). With the Knox, Ladybird is brought up short as the chain goes taut then relaxes into its catenary when I back off the throttle.
Click to expand...

+1 But the 18kg, replaced a 60lb CQR. I have hauled the anchor in by hand after a windlass failure, difficult but easier than the 60lb CQR. Has held well, sets quickly and strongly in mud and sand and tested under power. Boat is a Rival 41C.

There is a report of one picking up a stone in the gap between the flukes and Knox for a while offered to close the gap with a small bridging piece. I do not know if they still offer this but stated at the time that it was not required, just a buyers preference. I had this on a Danforth years ago but the gap is much larger and more tapered.

As far as I am concerned, a good anchor, works very well, is strong and built with quality, plus British made (which is important to me if I have that option).
 
vyv_cox said:
I now have one to test, 13 kg model. I can try to feed back impressions in a week or so, once my present battery confusion is resolved, supply problem rather than technical.
Click to expand...

Thanks for your info I look forward to your impressions after use - it is the 13kg model I am thinking of.
 
I have got the 9kg model with 8mm chain on a 32ft boat. It replaces a 10kg Bruce which I had no real quibble with though it had failed to set reliably a couple of times albeit in a long relationship. I will keep it as a back up.

Like BoB, above, it being UK made is a strong selling point for me. However it does stand up on it's own, as a product, for the solid construction and good surface treatment. I had previously decided on a Spade but been put off by the number of rusting examples you see.

It is physically quite big, it fits in my anchor locker but it's a fiddle. Certainly a Manson or Rocna would leave more room so do your sums. I liked to set the Bruce on a scope of 2:1 or less for short stops and the Knox seems happy with this mistreatment as well.
So I have not really tested it in earnest but it has brought up huge clods of mud on two occasions which the Bruce rarely did I am happy with this as a proof it is doing it's work - so right now I am very pleased indeed with it.
 
I have the 13 KG. Only been using it for about a month or so, but so far it has worked well, including a 120 degree windshift in Rothesay Bay that woke me up in the middle of the night with the boat bouncing all over the place, but the anchor held just fine. I did have to make up a new bracket for my pulpit bi-colour nav light to move it upwards and outwards in order to clear the roll bar. Build quality of the Knox looks excellent.
 
Neeves said:
CO8 - so what size of yacht and what size of chain? What were/are you using? and why are you changing?

Jonathan
Click to expand...

Hi
My boat is a 27ft catamaran (8m Catalac) and weight about 3.5tons. I use 50m of 8mm chain with a 16kg Delta at present and plan to replace that with a 13kg Knox. The Delta has been very good for me and has only dragged twice in 14 years of regular use, once in thin sand over rock and once in soft mud although my anchor fluke may have slid along the anchor chain of the boat behind me as when he came to go he had an enormous amount of chain out running where me anchor had dragged and in the same line,
Anyway the Knox has a bigger fluke area than the Delta it has a better concave scoop shape rather than the ploughshare profile which is acually designed to plough and the sharper flukes should give better penetration than the rather blunt point of the Delta. So Delta good and all indications are that Knox should be better.
Thanks for your response Jonathan, I always enjoy your detailed anchor and other thread contributions.
 
CO8,

I'd be happy to use the 13kg Knox as a replacement for either our 15kg Excel or Spade (noting we are using the equivalently sized alloy versions, 8kg each), reserving judgement on how the Knox works in rocks, pebbles and shells. I also think 8mm chain is also overweight - but if you've read my comments (and thanks) you will know my views!

I found using a 3/8th gal bow shackle, Crosby's G209A a bit tight in the shackle slot. It fits but might lock up. If you progress with the Knox I might look at the next size smaller. I have been using 3/8th shackles, which is why I used one in my Knox and don't have any 5/16" versions - so don't know (and I have to airmail Crosby ones from the UK). But contact Geoff - he sells shackles and he'll know what fits.

The reason I repetitiously suggest these specific Crosby shackles is that if you side load shackles, if they lock up, you reduce their WLL by 50% if you 90 degree side load and reduce by 25% if at 45 degrees - and the Crosby ones are twice the strength of most others (the 3/8th" have a WLL of 2t - side load it and it is still comfortably higher than the WLL of your chain) - and in the grand scheme of things they cost peanuts. I've tested shackles side loaded - the data and warnings have validity - and I've seen failed side loaded shackles (and know the, new, anchor was lost) - so it does happen.

We are 38', 22.5' beam 7t (cruising weight) so I think the 13kg Knox is over weight for you (but I am renowned for being minimalist) and even though I don't think you need that size/weight, you will sleep well (and that's what its all about!).

You will markedly reduce the impact of snatch loads if you use a decent, long, elastic, bridle and the combination of the Knox and a decent bridle (if you are not already using one) will be a real eye-opener. By 'decent' you should be looking at about 800mm - 1m stretch at 30 knots with a 10m, each side, bridle.

Jonathan

I've just looked and Crosby do not appear to sell that range of shackles in a size smaller than 3/8th". Campbell make the same grade but they are really only available in America and I think 3/8th" again is their smallest. Others make the quality, Grade B, but they are much larger, for example Van Beest. Peerless also make, again US, but the last lot I tested did not meet their own specifications (and they provided the samples to test!)

The best alternative is CMP's Black Pin Titan shackles - they are not quite as good (but better than anything else reliably available). Don't buy their Yellow (or orange, I see they now call them copper) pin they are no better than any other shackle.

I've now looked at the Titan range, they call them 'High Strength' and have a black pin. They offer a 5/16th" with a WLL of 1.1t (which is as good as you will, apparently get!). You still need a bow shackle.

http://titanmarineproducts.com/high-strength-forged-hot-dipped-galvanized-shackles

I think you will find them readily available in the UK.

But ask Geoff - he will know what fits (and whether I'm scaremongering!)

J
 
Last edited:
Just to add my two pennyworth. Purchased early in the year and I have spent every anchoring situation doing all the wrong things to see if I can find any weakness. I have been entirely unsuccessful. It just goes in and stays in.

I even tried in the thickest weed to the northwest of Old Harry in a force 5 and it held for two hours before slowly dragging.
To say that I am happy with it would be an understatement.
(37’ 7T and 13kg Knox)
 
You must log in or register to reply here.

Share this page

Top