Anchors

[vyv_cox]

I suspect that this thread is heading to be closed due to TNLI’s trolling.

He was banned from the FB Anchorages and Anchoring page for exactly the same persistent advocation of untrue and misleading 'facts' despite several warnings. Not only on anchors but on materials, fatigue, corrosion, where he was demonstrably talking nonsense.

 

[doug748]

Surely this is punishing everyone for the repeated misdeeds of one person. It effectively means anchoring threads are doomed to failure unless a more focussed penalty system is introduced.

Jonathan

It's difficult to boot someone out because you, or I, don't think he is right or is repetitive. Now and again people swim against the tide and are proved correct.
Probably best to skim nutty posts and only reply with one line or a suggestion for further reading.

Verbose posts and detailed rebuttals are simply not read by most folk, in the same way that the wonky original posts are ignored. We all write dodgy stuff now and again but the authors of repeated, illogical stuff are often only looking for that sort of attention.

.

 

[TNLI]

Accepting alternative views and opinions.

TNLI

Maybe you can define the names of these anchors and add them to your recommendations.

This first image I thought to be impossible but I think the ring at the crown was meant to be for the stock, which might have been wooden. I had thought the anchor to be simply a museum piece.
View attachment 151353

But like the Herreshoff such anchors are still in use today. This is a Chinese, PRC, Tuna boat in Suva harbour. I may do the crew a disservice it may be something else, but it looked like a tuna boat, and it had the self same (well almost) anchor, as above, on the bow.

View attachment 151354
View attachment 151355

So - its good enough for a Chinese vessel far from home - and the Chinese are not fools - as good as the anchors you champion?

Jonathan


Yes - it develops hold significantly higher than Delta, CQR and Bruce. It is easy to deploy, it engages quickly and it sets and holds reliably. Its not quite as good as the 'others' but it is very cheap (compared to the others). If it had a more robust shank it would be almost excellent (or given that you never use the full potential of any anchor - it would be excellent). I'm not keen on the folding mechanism - I bought one, carried from UK to Oz in our luggage (we had planned this) and had the shank welded to the fluke.

If you don't want to use a deck wash - don't anchor in mud but drop Supreme and Rocna from your list they both compress and retain the compressed mud (and weed). The Fortress is also excellent in clean sand - in fact in a predictable straight line pull its unbeatable. If the wind is going to move through 180 degrees and become much stronger and there is a chance of tripping - they can clog and not reset. (We would not be without ours).

Jonathan

Interesting anchors, not seen the bottom one before. The flukes and angle they are at are similar to an early Herreshoff, but the cross bar is not. Looks like a cross between a grapnel and a fishermans. Longliners have to anchor in deep water and with some very variable bottom types. Rust is only an issue if it effects the chain, as it will not pile up correctly. Steve of SV Penope fame did a test on how well new and rusty chain stores, and the rusty one needed twice the space in pile height terms. The first anchor is a modified fishermans that would be better in mud and sand, (Not great in either), than a cheap bar type. In think both anchors would be near impossible to bend or break, although the first one might be made of cast Iron which if hit very hard can break.

Still remember a Chinese long liner scream mayday after hitting Balls Piramid just off Lord Howe Island one night. I was in a local hotel bar that kept watch on ch 16. Moderate gale in progress but no one had a boat capable of running the entrance bar or dealing with the adverse sea conditions. No survivors, just debris the following day. Ilegal fishing can be dangerous and the sea around Balls Pyramid is far too deep to anchor. Incredible spot for yellow fin tuna, black marlin and sharks. Lord Howe has some of the worlds best fishing around its shores, with real big grouper and snappers, plus trolling plugs for kingfish close inshore. Incredible number of sharks so no swimming outside the net. Cheapish hotels, BUT fairly expensive flight from Sydney.

 

[TNLI]

He was banned from the FB Anchorages and Anchoring page for exactly the same persistent advocation of untrue and misleading 'facts' despite several warnings. Not only on anchors but on materials, fatigue, corrosion, where he was demonstrably talking nonsense.

If you read the links to the stainless steel company and the anchor tests Steve did, you will find I was correct on 99% of the points. That was why you stopped commenting about annealing. The warnings were all from folks who fail to read the links or who get upset that they had purchased the wrong anchor. Anyone selling marine parts hates a poster who says old proven anchors work better in terms of not bending, breaking or being too sensitive to weeds in particular. Real good designs get copied and so far no far Eastern company has tried to copy a new generation anchor, probably because the boat builders are going to stick with proven designs like the Delta and Danforth. 2 anchors that work well together.

Someone asked about rode or chain use.
First of all, an all chain rode will work better in short scope terms than a rope rode, and like anchors the heavier the better. So I use 4 times depth at high tide plus 10m, so my 2 main rodes are 50m, so I can't use a plow in more than 10m depth. Luckily each rode has another 50m of 3 ply long spliced to it. That means I can try using a CQR in 20m max. The CQR and all plows need more cope than a Danforth or most NG anchors. 4 to 1 normal, BUT as much as will not result in a collision with another boat for a storm. My Herreshoff copy should work in 50m.

You have no idea what you are talking about and simply spout absolute nonsense with not an iota of data to back your contentions.

The aluminium Excel has a shank made from the aluminium 7075 alloy of over 500Mpa. The shank thickness is increased (from memory) by around 50% over the steel version making the shank as strong as the steel Excel with its Bis 80 shank. There are no reports of the steel Excel shank bending and importantly no reports of the aluminium shank bending. I cannot be more accurate as I am in Suva and I don't carry all my technical date with me . I have been using this anchor for 10 years now as a primary - it has no bent.

On galvanising - Of the new gen anchors Spade is the oldest having been introduced in the 90's. It made no inroads in Anglo Saxon or Celt markets for many years but if you visit the French Pacific Islands or French marinas you will find anchors that are almost 30 years old - of course they have lost galvanising - its typically 70 microns thick, no wonder older Spade anchor rust. You simply do not see Rocna of that age - as they were only introduced in 2006 and took a few years to become popular.

I took this image of an original Spade in 2016 - not much sign of rust there (unlike the rode)
View attachment 151370

Basically you are trolling, disparaging product without a shred of evidence. and are doing so repeatedly.

Manufacturers might be upset (I wonder what manufacturers do to force a cessation in continued trolling?)

Jonathan

That anchor set up is a real mess, no way we know how often the anchor was used or if it was rubbed on the rocks. Practical Sailors articles shows they can be bent, and numerous owners complain about the rust. I'm not going to aquire another spade but I have said many times that the RNLI use them, and they do well in the tests. Very much top of the tables. They just need to make a Mk 2 without the yellow and with more galvanising. Alas any sharp pints tend to rust faster than rounder ones. The Excel copy of a Delta seems to be OK, although I wonder if it is heavy enough in weight vs area terms to work well in weeds.

I never, ever use a stainless shackle, swivel or anchor connector for a serious anchor. Very few makers bother to use real good stainless and fail to anneal, work harden or nitride treat their products, they sure do a nice polish job though and first class web site. Very short fatigue life and low shear strength. Some types of stainless also corrode rather faster than 316 should.

It's essential to check with boats anchored near to you to find out how much rode they have in use and if they have more than one anchor in use. The snubber 3 ply lines need to be adjustable, not just fixed length. Length of the boat minimum, but upto 20m max to a seriously good chain hook. If you have to use rope rodes, wind spiral wrap around the bottom part.

 

[Neeves]

Apologies.

Assuming an anchor has dug in and held presumably its holding power is a function of its cross sectional area.

Yet when i look through the manufacturers recommended anchors for my Nic 31, 6.5t. there seems to be a broad range of cross sectional area for tbe different anchors recommended.

From spade 20kg at 1000cm to viking at 743, via knox 690 and rocna 1030.

Currently sporting kobra 14kg but feeling underdressed.

Thoughts?

This is an usual thread in that the OP has raised questions on the value of 'technical' data, in this case surface area, but also because as the thread developed it became apparent that the OP was not questioning the lack of performance of his anchor but the fact it did not fit on his bow roller. Or it did fit but attacked the gel coat.

Its a bit late in the life of the thread, but I can be very slow despite my advocacy of a bit more lateral thinking in looking for solutions. - so my standard plea for pictures. I hate to see money being spent unnecessarily and if the anchor is acceptable, as an anchor (it holds) then maybe some pictures of the housed anchor might lead to suggesting as to how the anchor can be secured at sea without satisfying its need to gnaw at the stem.

I agree with the previous comments that a 14kg Kobra should be perfectly adequate for the yacht, 6.5t x 31.6 Nic, I'd actually suggest a 14kg Kobra a bit too big (which is maybe why the anchor does not house correctly). Before we went all aluminium and all lightweight we used a 15kg Excel (still have it gathering dust in my workshop) - 38' x 7t cat with the windage of a Bav 45. Prior to the Excel we had a Manson Plough (CQR clone) of around 20kg - it was a disaster - proving design is everything and weight is, well, just weight.

Ian - any chance of some pics of the anchor housed on the bow roller and the deck layout where the anchor joins the chain. My guess is the windlass is located well forward - but let us see and maybe we can solve the problem without the need for you to buy an expensive bit of steel (with a shorter shank). Now.... if you are miles from your yacht and have no pictures - maybe a few (thousand) words would allow you to describe the restrictions.


But I commend your initiating the thread in the face of heretic posters and the negativity by some to anchor threads. There should never be any fear in initiating any thread - that's what the forum is for, I condemn the worry about upsetting those who are bored with certain threads, whether its exhaust elbows or anchors. No-one needs to read threads they find boring - unless they are into self flagellation. I also commend you initiating the thread with a question on surface area.

Jonathan

 

[Neeves]

It's difficult to boot someone out because you, or I, don't think he is right or is repetitive. Now and again people swim against the tide and are proved correct.
Probably best to skim nutty posts and only reply with one line or a suggestion for further reading.

Verbose posts and detailed rebuttals are simply not read by most folk, in the same way that the wonky original posts are ignored. We all write dodgy stuff now and again but the authors of repeated, illogical stuff are often only looking for that sort of attention.

.

See Post 41, above. Some forum have found a mechanism.

Its not you or I, but many (and as it appears - across more than one Forum).

Jonathan

 

[sailoppopotamus]

I find anchor threads interesting, because anchor experiments are hard to conduct. Consequently, there's little data to scientifically, unequivocally, highlight the "best" anchor, and indeed, even defining "best" is a challenge in itself. So we end up with experienced sailors, each analyzing their theories about what makes an anchor good, why they prefer certain designs, and so forth. I know any anchor thread will never reach a consensus, but the discussion and various viewpoints offered will be worth reading.

In this case, we have the OP highlighting how much the anchors recommended by the various manufacturers differ in fluke size. An interesting prompt. Yet we haven't managed to even get to the second page without the conversation degenerating into a ramble about a specific 30 year old anchor, that hardly anybody has even heard about, and is barely even produced any more.

I propose that we all pretend to agree that the Herreshoff anchor is the best anchor, second to none except perhaps for a specific vintage of CQR, all other anchors made in the last century will bend or break if a fat fish rests on them, or not hold up in 2:1 scope when your engine and sails have both failed on a lee shore in deep water with a rocky or weedy bottom in F8+ winds. Now that we've agreed on this, can we go back to having literally any other conversation about anchors?

It's not that I don't find anchor threads interesting, quite the contrary as I've explained. But if I may voice my opinion, I think we're well past the limit where the Herreshoff anchor discussion continues to be of interest.

 

[TNLI]

Back on topic, this clip from Steve of SV Penope fame is interesting as it's for a Luke copy of a Mk 1 Herreshoff actually managing to hold at full power, even though the Herreshoff design is not good in sand and just average in mud.
Alas at the end of the day this is just a copy, as the real bronze Herreshoff is a different shape. Pity he can't get the real thing, although this is the type of anchor Don Street used. I keep looking in Google to see if anyone is selling the real late model Herreshoff, but alas they are not.

Fisherman Anchor Setting Test. 100 lb. Video #23 of an ongoing anchoring series. - YouTube

 

[TNLI]

Apologies.

Assuming an anchor has dug in and held presumably its holding power is a function of its cross sectional area.

Yet when i look through the manufacturers recommended anchors for my Nic 31, 6.5t. there seems to be a broad range of cross sectional area for tbe different anchors recommended.

From spade 20kg at 1000cm to viking at 743, via knox 690 and rocna 1030.

Currently sporting kobra 14kg but feeling underdressed.

Thoughts?

Alas anchor design is very complicated and although area is important, the angles and weight are also factors. It can take a long time for a company to develop a new design and select the best materials IF they are going to produce a real good tough rust free anchor.
If by Nic, you mean Nicholsen, then 14 kg is OK, but weight does matter, and as the Kobra is a sort of Delta copy, it will not work in cobblestones rocks or heavy weed, and does need at least 4 to 1 of chain.
I should have pointed out that if you have a sensible plow anchor, the secodary that should be deployed in adverse conditions, should be some type of fishermans, and the Herreshoff would be the one that works in rocks, heavy weed or mud with a 2 to 1 scope, although Steve of SV Penope anchor testing fame used 3 to 1 of rope. The other option would be a Spade as that also works in cobblestones and rocks to some extent, but will need a longer scope.
For safe anchoring it's good to have a second anchor that is good on a short cope.
Fisherman Anchor Setting Test. 100 lb. Video #23 of an ongoing anchoring series. - YouTube

Looking at the picture of the Plastimo Kobra, very surprised Lewmar have not filed a copyright claim against them, as it shure looks like a Delta.
Plastimo Kobra 2 14Kg Anchor Silver | Waveinn (tradeinn.com) I like the fact they put the name on it. Seems to perform the same a a Lewmar Delta in one test I looked at. Good in mudm sand, and OK in moderate weeds, but no plow works well in cobblestones or rocks.

 

[Neeves]

I find anchor threads interesting, because anchor experiments are hard to conduct. Consequently, there's little data to scientifically, unequivocally, highlight the "best" anchor, and indeed, even defining "best" is a challenge in itself. So we end up with experienced sailors, each analyzing their theories about what makes an anchor good, why they prefer certain designs, and so forth. I know any anchor thread will never reach a consensus, but the discussion and various viewpoints offered will be worth reading.

In this case, we have the OP highlighting how much the anchors recommended by the various manufacturers differ in fluke size. An interesting prompt. Yet we haven't managed to even get to the second page without the conversation degenerating into a ramble about a specific 30 year old anchor, that hardly anybody has even heard about, and is barely even produced any more.

I propose that we all pretend to agree that the Herreshoff anchor is the best anchor, second to none except perhaps for a specific vintage of CQR, all other anchors made in the last century will bend or break if a fat fish rests on them, or not hold up in 2:1 scope when your engine and sails have both failed on a lee shore in deep water with a rocky or weedy bottom in F8+ winds. Now that we've agreed on this, can we go back to having literally any other conversation about anchors?

It's not that I don't find anchor threads interesting, quite the contrary as I've explained. But if I may voice my opinion, I think we're well past the limit where the Herreshoff anchor discussion continues to be of interest.

I think we all agree, except one person. But as that one person takes not an iota of interest in other posts, including this one - you/we are on a hiding to nothing.

Either the Mods develop a strategy - or we live with it.

What are we going to do if he discovers the Bulwagga or Northhill or takes an interest in chart plotters and GPS.......

Jonathan

 

[Bajansailor]

What are we going to do if he discovers the Bulwagga or Northhill

The Northill appears to have a larger fluke area than a Herreshoff, so should hopefully have better holding power - but maybe not in these mythical cobblestones..... maybe it will work for when coastal high streets that are paved with cobblestones end up underwater due to global warming, and you want to anchor there to do your shopping?
Northill Anchor

@TNLI, thoughts re the Bulwagga?
Bulwagga Anchor - When you really need to be sure!

 

[SimonKNZ]

The genuine Lewmar CQR and Delta will never be in the same legue as modern NG anchors, as they are far too tough, too well designed, weed resistant, 180 degree veer proof

Wrong. Making false statements dressed up as facts again.
One of the reasons I changed from a Delta to an Excel was because the Delta let me down very badly in a 180 wind veer; it un-set and showed no signs of re-setting despite dragging for at least 100m. If you (TNLI) actually look at the tests by Panope, instead of just making stuff up, you'll see that the Excel outperforms the CQR and Delta in veer tests.

 

[TNLI]

Wrong. Making false statements dressed up as facts again.
One of the reasons I changed from a Delta to an Excel was because the Delta let me down very badly in a 180 wind veer; it un-set and showed no signs of re-setting despite dragging for at least 100m. If you (TNLI) actually look at the tests by Panope, instead of just making stuff up, you'll see that the Excel outperforms the CQR and Delta in veer tests.

Yes, BUT those tests are based on weight vs performance, not what the RNLI and myself refer to as deck area. So if you make an anchor that is more lightly built with thinner plates it will outperform the more solidly built Delta or CQR. Alloy anchors are the best example of why it's a bad idea to go thin, as the Fortress produces excellent holding in weight terms, BUT has a very large deck area, so might not fit where an older heavier ships anchor, (Very thick Danforth type), would fit. In the end if you check the deck area vs performance there is almost no difference. In reality a good plow like the Excel, CQR or Delta will perform in a very similar way.

So what is needed is a table of weight per unit of area, vs holding performance, and only one series of good tests that were discredited as too old, actually shows performance vs deck area, (Size if you like). So that fine table of results had a 35lb CQR vs a 10lb Fortress and the CQR was better etc.
Weight vs performance tables are in interest if you do not have a manual or powered windlass, or like myself, prefer to get some good exercise in. So the Exel is a good anchor for manual operators, BUT I think you will find that a more olidly built anchor will penetrate weed beds, which is why the RNLI tests rated the Delta as top dog, although they did not test heavy fishermans or the Herreshoff anchors. Unfortunately there are big differences between different types of fishermans and the copies of the Herreshoff, although the Lukes seem OK.

One of the reasons why the Delta is so polular and was chosen by the RNLI for their inshore RIBS, was that it is good in weeds and very tough. Very few other anchors can function in weeds, also none of the plows are particularly good in rocks and need more scope than Danforths, (Hopeless in weeds as they don't tend to reset).
Performance in weed is very important and a heavily built anchors with a higher force per unit area in footprint terms, will do better. So if Steve gets around to doing tests in weeds, the CQR could easily turn out to be better, as it's a tad heavier than the Delta in weight per unit deck area terms.

PS: The Spade does better than the Excel in any of the tests, including the old Practical sailor one of deck area vs performance. The combination of a Spade and a genuine impossible to buy bronze Herreshoff would be very interesting. Alas the cost of buying a Spade, (Rusty ones are almost free), and getting it hot dipped galvanised, (Most of my anchors are second hand pre abused), does not make sense. Looking for a good used 25lb CQR at present for a storm anchor, but still dream of a lovely bronze Herreshoff. I'm thinking of selling my small 2kg stainless Bruce, (Very good anchor apart from weeds), to help pay for the small dinghy one.

Anyone that drags 100m has not undersood what I keep harping on about, 2 ANCHORS ARE BETTER THAN ONE !! All it takes is one tin can on a point to ruin your whole day if you think one anchor in more than a light breeze or current is a safe way to anchor. I often just lower my secondary right below the boat and keep the rode on deck. The secondary does need to be a fast setter, not a plow, so Danforth or fishermans of some type, including Don Streets and my favoutite, the Herresshofd developed in the the late 1800's. OG's, (Old Generation). LONG LIVE THE OLD GENERATION ANCHORS!

Anchor Reset Tests - Practical Sailor (practical-sailor.com)

 

[TNLI]

When all about you say nay !! you are not doing something wrong. Lewmar, the RNLI and all those 4000 boaters who Steve of SV Penope fame said were not wrong, and the great tests done in the old days by Practical Sailor were not wrong. Even Steves test comparing the CQR and the Delta that resulted in even more nay sayers, have convinced me that I've really got to buy more old generation anchors.

Umm, I wonder if I can find a Bulwagga, as it beat the old genuine CQR !! MINE GOTT, it's back in production !!
Bulwagga Anchor - When you really need to be sure!

Stainless steel version too !!

 

[Neeves]

Wrong. Making false statements dressed up as facts again.
One of the reasons I changed from a Delta to an Excel was because the Delta let me down very badly in a 180 wind veer; it un-set and showed no signs of re-setting despite dragging for at least 100m. If you (TNLI) actually look at the tests by Panope, instead of just making stuff up, you'll see that the Excel outperforms the CQR and Delta in veer tests.

TNLI said

'The genuine Lewmar CQR and Delta will never be in the same legue as modern NG anchors, as they are far too tough, too well designed, weed resistant, 180 degree veer proof and certified to a higher standard than any of the NG anchors,'

More rubbish from TNLI (who has little on no idea about anchors and invents increasing fictional nonsense)

Delta is certified as a High Holding Power anchor by Lloyds. An anchor of the same weight as a tested Delta is awarded Super High Holding Certification if it develops twice the hold in the same, multiple, seabeds consistently over 3 'pulls'. Epsilon, Spade (steel) and Supreme are certified as a Super High Holding Power anchors by Lloyds. Rocna was certified by RINA as SHHP, Fortress and Ultra are certified as SHHP by ABS and Excel (steel) as SHHP by AMSA all under the same protocols as Lloyds. I am only aware of Fortress, as an aluminium anchor, being tested and awarded SHHP. All Classification Societies work to an identical testing regime for all their certification, not only anchors, and each accepts each other's test certification.

Weed resistant - where is the weed resistance of these 2 anchors....??




As far as I know the testing regime for Proof Testing for HHP and SHHP, completed as part of the certification, is identical. All SHHP anchors are tested for strength integrity. Viking has not been subjected to Classification Society testing (its expensive) but tests underline it develops a hold comfortably more than 2 times higher than a similarly weighted Delta and meets the Classification Society Proof Testing regime.

Unabated trolling again.

Jonathan

 

[john_morris_uk]

TNLI hasn’t responded in a while. Perhaps he’s finally revisited all the independent recent tests and read them properly and listened to the cumulative and extensive experience in these and other forums and realised how wrong he was on so many issues.

 

[TNLI]

TNLI hasn’t responded in a while. Perhaps he’s finally revisited all the independent recent tests and read them properly and listened to the cumulative and extensive experience in these and other forums and realised how wrong he was on so many issues.

JM has responded, perhaps he has finally revisted the links I posted and read them properly, and listed to sailors like Don Street who had real world cumulative and extensive anchoring experience in the real world, and realised how right I was on many issues !!

 

[john_morris_uk]

JM has responded, perhaps he has finally revisted the links I posted and read them properly, and listed to sailors like Don Street who had real world cumulative and extensive anchoring experience in the real world, and realised how right I was on many issues !!

I have read them all. I also know people who know Don Street. If NG anchors has been around when he was sailing round the world he’d have been the first to buy one. He is/was an eminently practical and sensible sailor.

What’s disappointing in your rants is that you keep quoting sources that are either out of date by many years or actually contradict your assertions.

You ignore the professional opinions of experts in metallurgy with your crazy amateur notions.

You dismiss any tests that PROVE you’re wrong by saying the testers were in the pocket of the NG manufacturers.

You make wild and inaccurate guesses about anchor design and derivatives.

What’s really disturbing is that newcomers to boating might actually believe your nonsense

 

[LittleSister]

I'm all for a bit of thread drift, but what we have here is the thread itself has stayed broadly on topic, ranging pleasantly around its original position, but it has now become seemingly inextricably entangled with something entirely separate, with just one person aboard, dragging around wildy, and with the skipper ignoring all advice, including from those who have known extensive and/or specialist knowledge.

It is best ignored, and one can hope that any relative novices reading the thread will be able to see for themselves which positions make logical sense and are consistent with the huge wealth of experience and knowledge represented by the consensus.

 

[LittleSister]

Meanwhile, back on topic (almost!).

A number of people have commented on the variation in the general tendencies - larger or smaller - of different manufacturers' recommendations for anchor sizes and weights.

I think that for manufacturers (e.g Kobra) recommending on the low side many people would err on the next size up, whereas for those such as Manson recommending on the upward side, many people would also err on the next size up!

I think the general differences in recommendations are to some significant degree reflective of their marketing to different types of customers, mores than to difference in boaters' needs or anchors' performances.

Manufacturers' recommends for my boat, just over 8m, and 4 tonnes
- Kobra 8kg = 18lb (n.b. the same Kobra's recommended up to 10m)
- Manson Supreme Coastal - 25lbs
- Manson Supreme Offshore - 35lbs

So do Manson really have such little confidence in their Supreme anchor that it needs upsizing 40% on a Kobra for coastal sailing, and 95% for offshore? Or could it really be true that the Kobra recommended sizes are inadequate? (I think my current Bruce copy is v. similar in size to the recommended Kobra - IIRC 7.5kgs/16.5lbs, so far adequate, but not severely tested. I'd rather have a NG than the Bruce-alike, but it doesn't look/feel undersized to me. )

I think we can (almost) all accept that it is an inexact science, and that one would need a lot more detail in addition to weight and or length to judge appropriate sizing, but then one runs into the lack of robust research into the different details of both anchors' capabilities in different scenarios, the different loads the different types of boats may put on them, and the variations in peoples skills, and the types of use and expectations of anchors.

I suspect that it is almost inevitable that recommedations for anchors aimed at the cheaper end of the market will lean towards smaller sizing - they are being sold at least partly on price and being adequate, while the premium product manufacturers will tend to encourage you to spend even more money on a larger size, assuming most of their customers will have money to spare. If you look at car ads, the cheaper makes & models will emphasise their economy and practicality, the premium makes models will emphasise additional optional extras and deluxe models that you 'really' need.

Looking at the Manson (premium) recommendations, for example, I found it interesting that anchoring for 'offshore' sailing requires spending more money than 'coastal' sailing. I sort of know what they mean - 'coastal' sailors are less likely to want or need to anchor in marginal locations/conditions - but who actually anchors offshore?, and you could think an 'adequate' anchor would be adequate whatever. (Many people will 'go up a size', even if the recommendations have already done that once, and when their actual intended sailing/anchoring is perfectly normal. Anchor size inflation!)

Curiously, Manson suggest that traditional anchors suit traditional boats, and vice versa, which I find highly questionable.
'The New Generation anchor range use materials and designs suited to the latest boat designs.' and 'The Traditional anchor range uses classic designs like the Plough (CQR) or Ray (Bruce) Anchor suited to older boat styles.'

Their anchor size calculator appears to allow you to get sizing recommendations on traditional anchors ( CQR and Bruce), but it doesn't, and when you've inserted your boat size etc. details it instead invites you to contact them for advice. No doubt for a pep talk on the advantages of the Supreme over the dangers of old generation anchors!

Also surprising, and somewhat contrary to my hypothesis about marketing, are Manson's chain size recommendations for my boat, they suggest 6mm to 8mm chain. Most traditionalists would have kittens at the idea of a 6mm chain on an 8m, 4 tonne boat. Even leaving that aside, the recommended juxtaposition of 6mm chain with a 35lb/16kg anchor does give one a start!