Don't drag your anchor!

[Neeves]

Yes same for me, i.e. no windlass and adding weight to the bow is something I really need to avoid if at all possible. BUT my thinking is that going too big probably means I'm going to find it difficult to set properly and if I can't set it properly it's ultimate holding power is an irrelevance. Therefore I'd be more inclined to opt for an anchor that's at or only slightly over that recommended for my boat's size. I was erring towards a Mantus, then a Rocna, now maybe a Spade or should I consider a Fortress, all because I'm not happy with the CQR I currently have and now my head hurts...

I'd suggest you need to carry a Fortress, anyway. They seem to come up, in the UK (so I'm told) fairly regularly on eBay, Sarabande pointed one out recently but it was a FX37 (quite big). But I recall other members have bought smaller ones. The Fortress is excellent if you need to kedge off, its good in sand and mud and unbeaten in squishy mud. I would not use it in weed nor stony anchorages. Its also knock down (though I recommend it is carried assembled so ready to use). It is relatively flat (you can store it tied to the transom) Of the other anchors and it will be your primary, I would suggest Spade as it is knockdown and you mentioned that as a criteria for choice. I would not touch a Mantus, for the reasons outlined in the link in post No 9. If you value hold in an anchor then to buy a Mantus of the same hold as a 10kg Spade or Rocna you will need a 20kg Mantus. If you want the hold of a 10kg Delta - you will need a 10kg Mantus. Spade also does not carry Morgan's Cloud negativity for clogging. If you want to keep weight down in the bow then the aluminium Spade is an option. If you know people going to and from OZ I can recommend the aluminium Excel, we have used one for years as replacement for our steel Excel. In small sizes aluminium anchors will fit into checked in luggage. You could also try Anchor Right and see how much it would cost to airfreight one to you.

If you do need to retrieve by hand then aluminium anchors are so much easier than the steel versions. Our Spade and Excel both weigh in at around 8kg and are the same size as the steel versions each weighing 15kg. The extra weight is noticeable but more noticeable if you have to carry them down the side deck. 15kg is not that heavy - but becomes so on a moving deck when you need to squeeze round shrouds etc of deploy from a dinghy.

Jonathan

 

[zoidberg]

VY1701 said:
Yes same for me, i.e. no windlass and adding weight to the bow is something I really need to avoid......... that recommended for my boat's size. ......now maybe a Spade or should I consider a Fortress

Much in this sort of discussion is determined by your boat - size, weight, shape - and where you will and where you won't be anchoring. Oh, and how much money is available for that kit before the wallet is in serious pain. There's something of a consensus, I believe, that no ONE anchor/rode provision will be ideal in all circumstances, but that one really good 'hook' will do the job on 80% of occasions. Knowing the possible limitations means you avoid the difficult places - or buy another specifically for those, with some useful 'capability overlap' .

I've bought into the same decisions as those recommended by Neeves above - and by rather a lot of others. The best 'primary' anchor I have is a 14kg steel Spade. I also have a Fortress Fx-16 as the secondary 'hook'. Both these were acquired Used ( here, eBay, Gumtree.... ) and at well less than dealers' prices.....

I've used several anchorages where the Fortress is clearly the preferred choice, due to the known nature of the substrate.

It's my choice to keep both stowed below, until I want to prepare them for use. They both 'demount', and I keep the Fortress in a carpeting bag I've made, having changed the fiddly little fixing bolts for others I can reliably use without tools. Two minutes is what it takes me to assemble and clip on, ready for use.

The argument about the nature of anchoring rodes continues. I've opted for 100 metres, half-chain and half-rope, with more rope available if ever needed. I'm sure others will have different preferences, and I'm OK with that. And 'yes' to snubbers, when warranted.

There's also the option of the Kobra 1 ( folding ) plough type, which could substitute for the expensive Spade. Here's a link to the selection charts for Fortress and Kobra....

Fortress selection chart

Kobra selection chart

 

[noelex]

Yes same for me, i.e. no windlass and adding weight to the bow is something I really need to avoid if at all possible. BUT my thinking is that going too big probably means I'm going to find it difficult to set properly and if I can't set it properly it's ultimate holding power is an irrelevance. Therefore I'd be more inclined to opt for an anchor that's at or only slightly over that recommended for my boat's size. I was erring towards a Mantus, then a Rocna, now maybe a Spade or should I consider a Fortress, all because I'm not happy with the CQR I currently have and now my head hurts...

All the anchors you have shortlisted are excellent. You cannot go wrong with any of them.

In terms of the outright performance, the best is the Mantus M1. I swapped from a Rocna to an identical sized Mantus on the same boat. Almost 2000 nights anchored with the Rocna and 1000 nights anchored using an identically sized Mantus provided a great comparison, especially as on many of these occasions I dived to observe the performance of the anchor and those of other boats nearby. The Rocna was great, but the Mantus has the edge, especially in thick weed that is a substrate all modern anchors find difficult. However, the long tapered fluke and wide roll bar make the Mantus difficult to fit on many boats, so the Rocna or Spade may be a better fit.


The Fortress is an excellent kedge. Its high holding power in a lightweight package is excellent in this role, but I wouldn’t use it as a primary anchor. It has too many weaknesses, particularly the tendency to break out if there is a significant change in the direction of pull. Also, be wary of the aluminium Spade. It is still a good anchor but cannot cope with hard substrates like the Steel version.

Without a windlass, anchor weight is important so I can understand your decision not to oversize the anchor. If you do decide to go a little larger and have an inboard engine, don’t worry about the setting performance. Despite a significantly oversized Rocna or Mantus, generally we have still had the best set anchor in the anchorage. We usually stop after applying about 30 seconds of full reverse, but if you want to set the anchor deeper just continue this a bit longer. Generally this is not necessary, as if the wind picks up the anchor will bury deeper so there is no risk the anchor will not reach its ultimate holding power.

You can look at my photos of our anchor compared to surrounding boats and make up your own mind. I photographed every anchor within diving range for over two years so there are plenty of examples. Modern anchors, particularly the roll bar designs such as the the Mantus and Rocna, set very rapidly and this helps them efficiently convert the setting force into digging into the substrate. In contrast, older designs drag for many metres before they even think about burying so they need more force and finesse to set

Modern anchirs are fantastic. I suspect you will be surprised at the difference. Make sure you are hanging on when setting, many are caught out by the sudden jolt as these better anchors dig in.

 

[doug748]

Yes same for me, i.e. no windlass and adding weight to the bow is something I really need to avoid if at all possible. BUT my thinking is that going too big probably means I'm going to find it difficult to set properly and if I can't set it properly it's ultimate holding power is an irrelevance. Therefore I'd be more inclined to opt for an anchor that's at or only slightly over that recommended for my boat's size. I was erring towards a Mantus, then a Rocna, now maybe a Spade or should I consider a Fortress, all because I'm not happy with the CQR I currently have and now my head hurts...

I really got it down to Knox, Rocna, or Manson Supreme. The construction of the Manson seems good to me and the Knox is very strong and well finished. I didn't want an anchor that comes apart and I have spotted some Spades with corrosion on them.

I bought a Knox (9kg) and found it was just a little too big to be comfortable in my locker - in fact if the chain shifted it could get jammed in there. So it was sold and I ended up with a 10kg Rocna which is slightly smaller. I don't know why as I do like the look of the Manson but there we are. I don't think you will go far wrong with any of them.
Your problem, I guess, is do you go for the 10kg option or the easier to handle size down.
The only thing I can say to help is that I only use my winch to pull the boat up short in strong conditions and this is the same regardless of the size of anchor.

 

[geem]

Here in Antigua we have had a few days of strong winds. Squalls in the high 30s/ low 40s with one squall over 50kts. In Falmouth Harbour nobody dragging but the holding is good. Speaking to a guy we know on a catamaran who was up in Green Island when the 50kt squall went through, he said they dragged and also another catamaran. Both cats were using Rocna anchors. The bottom is grass. He said they have had issues before with the Rocna in grass and high winds. He is now looking for another anchor so I suggested he look at Spade. Cant fault the performance of a Spade anchor in grassy bottoms.

 

[Neeves]

Noelex - the trouble is you have hung your hat on Mantus - If you do not understand then the following will be an eye opener - and not before time.

Please see the link I posted earlier. Instead of ignoring it, ostriches come to mind - please comment on where it is wrong.

Mantus is an unballastef fluke anchor, its a simple plate, slightly bent - but it has no ballast.

Other unballasted fluke anchors would include, Danforth, Fortress, Bugel, Bruce, Knox, What all these anchors have in common is their crown is on the heel - the crown of the Bruce is actually behind the heel.

The crown of the Mantus is located where the crown of a ballasted anchor is located, such as Rocna, Spade, Excel, Supreme, Ultra. (roughly 1/3 of fluke length forward from the heel)

Research, lots of it, clearly demonstrates that crown location determines the hold developed

For some simple tests look at

Kim 'Upper bound analysis for drag anchors...'2005 - from memory pages 169/170.

If you want to argue just check the location where the work was done and the senior academics that are mentioned.

Kim provides an excellent reference list, some of which where the work overlaps on crown location are in agreement with Kim.

The result of having the crown in the wrong location allows the anchor to develop a fluke/seabed angle of 16 degrees - this will give (for 2 similar anchors of the same fluke size) a 50% reduction in hold. Every, almost, other anchor Rocna, Spade, Excel etc has a seabed/fluke angle of 30 degrees and the NCEL have a simple formula to compare anchors, of the same size but different fluke seabed angles based on the sine of the angle - and the sine of 16 degrees is 50% of the value of sine 30 degrees - and tests I have conducted on similarly sized anchors show - that the Mantus has 50% of the hold of a Rocna.

There is a wealth of data supporting what i say - I might direct you to a book by Puech 'The use of anchors in offshore petroleum operations' in which he reports tests on a model anchor, not unlike a Danforth, and clearly demonstrates the fall off in hold when the fluke angle is 16 degrees, rather than 30 degrees. The NCEL have done similar work.

This is a link to the specific page in Puech's book quoting the graphed results of the tests conducted on use of different fluke angles (which translate to fluke seabed angles (just think of a Fortress)

The Use of Anchors in Offshore Petroleum Operations

When you have conducted your own research please do come back and tell me I have it all wrong - in the meantime please stop promoting a product that has the hold for the same weight of Delta and suggesting the anchor has the hold of a Rocna.

Your anchor is 50kg - and if you have any sense it will be 60 kg. Rocna would suggest for a yacht your size a 33kg model - or maybe the next size up. Please advise the QUANTITATIVE tests you have conducted that show your oversized Mantus is of the same performance as a Rocna.

Many people are going to listen to what you say and simply buy an anchor of the recommended size and the result is their spancking new anchor will have the hold of a similarly weighted Delta or CQR. Many people's experience with a Delta and CQR is that it has a higher propensity to drag than the anchor with which they replaced it - a similarly weighted Rocna or Spade. I would prefer people buy their anchors with the maximum of information from reliable sources - and I think Puech, Kim, NCEL are better than your gut feel. If there is hold data available from the manufacturer of the Mantus - please add to the debate - and maybe advise if it is not available what quantitative data a buyer might rely for his choice - other than gut feel, again.

And I have taken my 15kg Mantus and moved the crown aft, as far as I can without jeopardising integrity (and having the fluke fold up), and tested it - I improved the fluke/seabed angle to 26 degrees and had a commensurate increase in hold. The theory and all the literature appears correct. Now I don't suggest anyone drills holes in their Mantus as I have done - it may weaken the fluke critically - its actually a simple fix that the manufacturer could make - and supply replacement flukes.

Its about safety.

Jonathan

 

[V1701]

Thanks to everyone that's replied to the comments I've made, I really appreciate it. Having read and re-read what everyone's had to say on this and other threads as well as elsewhere I think I have now made the decision to go with a 9kg Knox which I'll be able to stow under one of the forward bunks on longer passages. That's the same place where the Mantus I had previously "decided" on was going to go as well. Boat is a Bowman 26 long keel, no windlass. I wouldn't want anything on the bow roller for any length of time even if it would stay there securely so the Knox will sit on the foredeck or inside. I'm planning to take a year off work from next Spring, probably heading south from UK to Med. There is already a Danforth of sorts of a reasonable size with some chain and a decent amount of rode on board and for the Knox 15m of 6mm chain plus 80m of rode with an additional 15m of chain that can be added if necessary. I think I'll set off with that lot & see how I go, of course you can never have too much practice but I am half way reasonable (I think) at anchoring having previously kept a boat in Greece for a few years. Watching some folk trying to anchor makes you wonder what's going through their heads. Or more to the point what isn't...

 

[Neeves]

Thanks to everyone that's replied to the comments I've made, I really appreciate it. Having read and re-read what everyone's had to say on this and other threads as well as elsewhere I think I have now made the decision to go with a 9kg Knox which I'll be able to stow under one of the forward bunks on longer passages.

Before John Knox died he and I corresponded over many years on anchor testing. When he had unveiled his new anchor he generously gave me one to evaluate, which I took home as part of the luggage allowance (a mere 13kg - I had warned my wife in advance and she packed frugally).

It is an excellent produce, sets quickly, hold tenaciously and has the hold similar to similarly sized other good anchors - I measured it.

I had a few quibbles.

I though the pockets in the flukes might collect mud and I suggested that the drain holes be enlarged slightly so that a hose might more easily clean the 'innards'. The issue is 2 fold - if the mud is left there it will alter the balance from what John intended (and he knew his stuff and researched properly) but maybe more important if the pockets are left with mud inside then, depends how it is stored, the mud will be damp and or allow the pockets to hold water - and the gal will last less long compared to the pockets being thoroughly clean. Mud is the silent assassin of gal.

I was uncomfortable with the slot between the flukes as I could see the slot catching small obstruction, pebbles, shells, wood and larger obstruction, grass. I suggested that the slot be closed at the toe, simply sealed off - leaving the rest of the slot 'as is'. When I test anchors I now have a rough idea of what hold to expect and when I test, for example a Rocna or Excel, and it drags prematurely I am immediately suspicious. I test in the intertidal zone and I leave the 'poorly' performing anchor, wait till the tide recedes (now you might part understand why I dry out ) and then dig the anchor out carefully. What I inevitably find is that an anchor performing below expectations is that the toe has impaired something, shell, wood, seaweed stalk - and it is this contamination of the seabed that causes the, or )any, anchor to 'drag' - and is nothing you can plan for, except set your anchor alarm). I would discard that result in my testing, curse quietly as testing is hard work, and make another set on another tide. So....catching something in the toe - that would concern me - but maybe it does not happen.

The slot itself allows water to escape when the anchor is setting (as the seabed is squeezed by the developed pressures) - so the slot is advantageous. I can see this when I set in wet sand, but no water, as you can see the water running out of the slot.

I don't use my Knox regularly - but I do use it to compare with other anchors - and I have a couple of new (yet to be released) anchors that I have also been asked to evaluate - and the Knox, Rocna, Spade, Excel makes good models with which to compare.

The Knox is extremely well constructed - bullet proof, unlike some anchors that have surfaced in the past. It would not fit on our bow roller - which is one reason we do not use it - and when we deploy - we do so by hand (and retrieve similarly). We use a hammer lock, rather than a shackle, because a shackle that fits does not fit our 6mm chain (I have the hammerlocks Armorgalv coated (but you could have them galvanised - speak to Geoff).

I might suggest you have a word with Geoff over my comments and identify his view based on the very many anchors he has sold - and subsequent feedback. If my ideas have any merit he might have a fix.

If I were to use my Knox regularly I would simply bolt 2 heavy stainless washers over the entry to the slot, maybe 20mm back from the toe with a low profile nut and bolt.

I might add that a Danforth and Fortress have a similar slot and Danforth has been around for almost a century (though it has morphed considerably since it was introduced), Fortress 3 decades and they have felt no need to close the slot. Equally our Spade has a 'pocket' in the ballast chamber and it does not collect mud or sand - so possibly my fears are unfounded. I'm not suggesting anything fundamental just a bigger pair of drain holes and a 'weld' across, or just behind, the toe. There may be excellent reasons why, what I suggest is both unnecessary and would act to the detriment of performance.

Jonathan

 

[doug748]

I ran Waxoil into the open flukes of the Knox, I had intended to do this each year. Grease would do a similar job.

 

[Neeves]

Interestingly the published results of research titled:

'Upper Bound Analysis for Drag Anchors in soft clay' by Kim (that I mentioned in Post No 26)

was conducted in Texas - the home of Mantus Anchors. There are a number of copies on the internet, some are free.

If you are interested in anchors it is an invaluable piece of work as Kim goes through a series of variables, shank length, shank location etc. He conducts 'laboratory' tests to illustrate the performance differences in altering these many components and cites references to support his work. Basically it appears to be a guide for anchor development. However the work is limited to unballasted fluke anchors, Danforth, Bugel etc. The work does not extend to ballasted anchors, like Rocna etc. though some of the tests are applicable

Publication was in 2005 or 2006, depends on who you source from, a bit late for Rocna and Supreme. However much of the work that Kim details will have been done previously by others (I am sure Danforth did much the same work) - the advantage of Kim's work - its all in one place.

One of the Co-Chairs of the examining committee is Aubeny who is a giant in the world of anchors. Many of the references provided are giants of a similar stature - some are worth reading (many are heavy going )


If I seem critical of Mantus, I am - as they do not appear to have done their homework (I could go on but will resist the temptation). But they made no claims of performance (though they did have some rather biased videos (the dangers of video). But they are selling an anchor - I, for one, expect the manufacturer to ensure their product is shown in the best light. Most of the claims for excellence were made by one individual - and who needs to make claims when you have help like that!

The over riding lesson is - don't buy an anchor that has no holding capacity data available - on what other criteria can you choose an anchor? Be cautious of data from the manufacturer - but if independent data is missing and there is nothing forthcoming from the manufacturer - maybe keep your wallet closed.

There are plenty of good anchors that have been tested to varying degrees - Rocna, Manson Supreme, Kobra, Fortress, Excel (aluminium and steel), Spade (aluminium and steel), Ultra (only stainless), Knox - my apologies if I have missed some (blame my memory, not bias). There are anchors awaiting release and/or testing, Lewmars new steel models and Viking from Israel, not forgetting Lewmar's Fortress clones (that I have not seen nor heard any user reports) and Rocna's new addition Vulcan. If you are in the market - surely there is something here - with sensible, credible holding capacity data.

I do like the videos of Panope - but the performance is being judged under engine power - and winds can develop considerably more tension in the rode. Invaluable but buyer be cautious.

Jonathan

 

[vyv_cox]

My testing of the 13 kg Knox in the Mediterranean was not so positive. It set OK and held in the typical hard sand of the Aegean, although never buried as deeply as my 15kg Rocna in identical conditions.
In the typical weed of the area its somewhat blunt, L-shaped tips mostly failed to penetrate and it dragged, upon which the slot packed with weed that needed to be cleared, somewhat laboriously, before the next attempt.
Elsewhere in this thread the need for a sharp tip to penetrate weed is discussed. Unfortunately this is an attribute not possessed by the Knox, putting it on a par with the Bruce, also poor in weed for much the same reason.

 

[Neeves]

It seems that Noelex’ has known all about the low fluke seabed angle of his Mantus for some time and in fact he implies it is the, or a, reason he chose the Mantus. As he rightly suggest a low fluke angle (and sharp toe) is recommended for hard seabeds but the lowest fluke/seabed angle I have ever heard of is an angle of 22 degrees (not 16 of the Mantus) nor 30 degrees of most other anchors and the 22 degrees was chosen (by a Classification Society) to ease retrieval (and this reason might be food for thought for those that own a Mantus.)

See post 200

Anchors, Guns and Strippers!!!! - Cruisers & Sailing Forums/

Now what is interesting and now remains unanswered that if he knew of this amazing advantageous characteristic he did not think it important to tell anyone else (until now). And he fails to answer the key question ‘why does he think the advantages of anchoring in a hard seabed outweighs the loss of 50% of hold (compared to a similarly weighted, say Rocna).

He will, opt course, be claiming as his own the detection of this amazing and positive characteristic.

The other question is - if Noelex knew about the advantages of the 16 degree fluke seabed angle being so critical for a hard seabed why did no-one else know. I would have to assume that the designers of Mantus realised this was critical (and they don't mention it) . Why is this function missing from every other anchor, Rocna, Spade, Supreme, Ultra, Knox, Excel, Kobra, Fortress. There are a rather large number who made the mistake of sticking with the 30 degree fluke/seabed angle. The skills of Mantus Marine and Noelex know no bounds. Reading post 202 it explains Noelex knowledge base - as he obviously knows all the Australian coastline much better than most. I had not realised that the hard and rocky seabeds in Tasmania are actually quite exceptional -= but then I note Noelex background and he has obviously found that all other seabeds off Australian waters are soft sand, see Post 202

Noelex of course is using a 50kg anchor and the Rocna recommendation for a 50’yacht would be 33kg (and I have this sneaking suspicion Noelex anchor is actually heavier than 50kg - but I may be wrong - sneaky suspicions are like ‘gut feel’ hardly supportable. But if you have bought a Mantus - do realise it has half the hold of a similarly weighted Rocna - but will work in hard seabeds defeating every other anchor. Personally I think seabeds that are that hard (and not solid rock) are mostly illusory.


I assume now that the cat is out of the bag we will see a whole rash of new anchors with fluke/seabed angles of 16 degrees.


I’ve asked this before - how many times have people’s anchors been defeated by hard seabeds?

Jonathan

 

[vyv_cox]

I’ve asked this before - how many times have people’s anchors been defeated by hard seabeds?

Jonathan

One location for me, many years ago. Just outside the entrance to Pwllheli marina, where surf breaks in S winds. 15 kg Delta anchor. It utterly refused to bite despite repeated attempts, just dragged along the bottom. All sand, no weed.

 

[dom]

I’ve asked this before - how many times have people’s anchors been defeated by hard seabeds?

Jonathan

Often! But only using a Brittany anchor which basically any sand would defeat?

In fact, can I propose the Brittany as the worst anchor ever in anything other than nice firm mud?

 

[sailaboutvic]

With a new season about to dawn on us, comes anchor thread .

I thought the video was a good starting point for newbee , it took in some good points like removing the miff of 3:1 scope, taking in the distance of the bow distant from the water when allowing for how much chain to let out and making the point of setting the anchor.

To us old hands the info isn't much use but to new comers to anchoring its very useful info,

maybe we shouldn't mock the OP for his efforts.

If any of the three points I mention early get through to some taken up anchoring the video will be well worth the time the OP taken to make it .

Has for the type of anchor we all use , there a wild range of info out there which at times can be confusing ,

if I walk up and down the pontoon while having our winter break from cruising 9 out of 10 will have a NG anchor, every third boat will have a Rocna/ Spade on the boat and many will have a Fortress somewhere on the boat .( that's include us too )

Newer boat say newer then two years old will have A Delta I guess the reason for this is because many new boats come with a Delta and although I personally think a right sized Delta works well in the right conditions,(well it did for us ) but I willing to bet they many will change they Delta for some thing else.

 

[NormanS]

A marina is a poor place to carry out an anchor survey. ☺

 

[vyv_cox]

My informal survey says that the Delta is probably the most popular anchor in the Med because so many charter boats carry them. In a marina, where most boats are privately owned, NG anchors would seem very popular but not in the population as a whole.

 

[NormanS]

My anchor has been defeated by hard ground. Croic Harbour in the Monach Isles, is not actually a harbour, but a wide sandy bay, but part of it is just thin sand over smooth rock.

 

[Rappey]

Researching what anchor to buy I have watched so many "anchor shootout" videos on beaches, in shallow water, at depth using all sorts of setting angles and scopes on all sorts of seabeds etc.
What I can say is the modern anchors do appear to outperform older designs. I Have seen rocna, spade, mantis etc all out perform each other but also seen each one getting dragged around the sea bed failing in what looked like good conditions.
I can only conclude that what anchor to have is wholly down to a personal choice or maybe it's because it's what everyone seems to have for that area.
No single anchor stood out as best overall in multiple videos.

 

[sailaboutvic]

@ NORMAN...
It wasnt a anchor survey but if I was going to so one it be more likely in a marina then diving under boats at anchor and digging up their anchor