Deliberately starting an anchor thread.

[Zing]

I spent maybe a thousand nights at anchor in the last decade. A third of that with the Uncequr anchor until I gave it away to a local. The rest of the nights were with an oversized Rocna. You couldn’t pay me enough to take the Uncequr back. It’s crap in comparison.

 

[JumbleDuck]

I spent maybe a thousand nights at anchor in the last decade. A third of that with the Uncequr anchor until I gave it away to a local. The rest of the nights were with an oversized Rocna. You couldn’t pay me enough to take the Uncequr back. It’s crap in comparison.

By definition it was too small. Any type anchor will work if you buy a big enough one!

 

[GHA]

I have been poking about in my bookcase.

The Hiscocks carried two 35lbs CQRs in Wanderer III, with 45 fathoms of 5/16” chain, no windlass.

He records that they dragged twice, at English Harbour (q.v.!) in soft mud and at Ascension Island in volcanic cinders.

HW Tilman carried a 60lbs CQR as his bower anchor with a 112lbs Fisherman, a 45lbs CQR and a 25lbs CQR as spares (we lost the last three getting off in Freemansund).

Wonder what they would use today.........

 

[geem]

Am I the only person on this forum who has a NG anchor that isnt oversized? We have a well used spade selected off the Spade selection chart. It sets. It holds. We sleep.

 

[GHA]

Am I the only person on this forum who has a NG anchor that isnt oversized? We have a well used spade selected off the Spade selection chart. It sets. It holds. We sleep.

Suspect you're not. I've a 20Kg rocna which was near flawless for years though now a size up 25kg spade as well. Both just work. Other than a few quid no downside to having a bit bigger as one of the options.

 

[Zing]

Suspect you're not. I've a 20Kg rocna which was near flawless for years though now a size up 25kg spade as well. Both just work. Other than a few quid no downside to having a bit bigger as one of the options.

I’m oversized too. It’s a total no-brainer.

 

[Kukri]

Going back to 1911, here’s what Claud Worth has to say:

Design of anchors:



And sizing of anchors and chain:

 

[Neeves]

Minn,

Bizarre!

Claud suggests a 45lb, for a 7t vessel, what I might have called a Fisheman (nee Nicholson) that has a hold 50% of a CQR/Delta/Bruce and the triumvate have half the hold of a 2nd gen, Spade et al. The size of the recommended anchor for our cat is about 45lb, whether Fisherman, 1st gen or 2nd gen. Chain size is the same. We chose to go down a size when we chose our 2nd Gen anchor - in good company with Geem and a silent number of others.

Go figure

Geem's experience is interesting as though anchors are defined, usually, by weight - a Spade has a smaller surface area compared to a Rocna (and I suspect Supreme) for the same weight. Spade also tend to recommend slightly smaller anchors, by weight - than Rocna, Supreme and Excel - this difference become more marked as the anchors (or vessel) get bigger. This is taken to the extreme with Mantus, which has no ballast, whereas Rocna and Supreme (and obviously Spade and Excel) are ballasted. Many people believe surface area is the key to hold, a slightly questionable conclusion when one thinks of Spade (and Mantus - which has low hold for its area).

Its design, not weight.


No wonder people make anchors - there is money in it.

Jonathan

 

[Neeves]

Suspect you're not. I've a 20Kg rocna which was near flawless for years though now a size up 25kg spade as well. Both just work. Other than a few quid no downside to having a bit bigger as one of the options.

Having been critical of others - possibly you can outline, preferably with some examples - so much better than gut feel, of the upside to your larger investment. Like lambs to the slaughter (and I'm sure there is something comparable in 'Animal Farm' ) people follow the adage that 'bigger is better'- i am very happy to believe you are correct - but I'd prefer something substantial to underpin the assertion. I'm a bit more canny with my cash.

Because I say so - does not cut much ice - actually it cuts no ice - for me and a number of others.

What I find of long term cruisers, contrary to what you say - they carry the recommended sized anchors and a number of spares of different designs. There are exceptions - some carry anchors so big they are really portable moorings (and rave about their anchors and repetitively imply one should follow their example).

Equally interesting those in the 'bigger is better' camp have an evangelical zeal - and have no time for the silent majority (and a few here are not silent but not strident either). For the bigger is better camp - its black and white - or as articulated a 'no brainer'. I am happy to accept I am, lucky, and wrong (but would like evidence of my faults) - those in the 'bigger is better' camp have no time for those of us with luck on our side, they are right - there is no debate to be tolerated - despite examples to the contrary.

Jonathan

 

[Neeves]

The Northhill was held in high esteem by Bob Griffith (Ahwanee”). Unlike the CQR, which was used by RAF Sunderlands. it really was intended for flying boats. A real swine to stow and probably extinct now.

Our Victorian forebears seem to have gone through a phase of being as obsessed with anchors as we are, but theirs were all variations on the Fisherman theme - the Trotman, which had hinged palms, etc.

I notice that the CQRs sold by Lewmar have fabricated shanks; no more drop forging. Sic transit British Heavy Industry.

You can see Northhills or variants on big fishing in the Pacific Islands. I've never seen an original, or don't know I have, the ones I see look welded up variants.

Thinwater uses one - because if folds flat for his flat locker.

No longer are CQRs proudly embossed 'Made in Scotland' but fabricated in China (I believe Qiungdao where the Delta has been made for some decades).

Jonathan

 

[JumbleDuck]

I’m oversized too. It’s a total no-brainer.

I wonder if the anchor companies have realised this and reduced their recommended sizes?

 

[Kukri]

I thought it would be interesting to post Claud Worth’s recommendations - we may usefully keep in mind that these are for anchors used by sailing cruising yachts which either had no engine or which had a very small engine and seldom used it. Basically everyone anchored under sail and got their anchor under sail. Worth goes on to say that some people have hydraulic (reliable) and electric ( less so!) windlasses but that these are not necessary or helpful in a boat of less than sixty tons!

Hiscock says that a CQR may be half the weight of a fisherman type so long as it’s at least 30 lbs.

 

[LittleSister]

Bizarre!

Claud suggests a 45lb, for a 7t vessel

Note that's 7 tons Thames Measurement, not displacement.

 

[Neeves]

I've a 20Kg rocna which was near flawless for years though now a size up 25kg spade as well. Both just work. Other than a few quid no downside to having a bit bigger as one of the options.

Dear Sir,

The perfect opportunity for you.

Your 20kg Rocna was 'near flawless' (and to me anchors work or they drag (with nothing in between) - so why was your 20kg anchor, flawed, slightly or largely - what prompted you to 'up-size' (to a 25kg Spade- as you would not detect the difference in hold (unless you use a load cell every time(like the Knox Anchorwatch) with a 5kg difference in anchor weight. It would be useful to know yacht characteristics and the conditions under which it was not flawless.

The information may well support your contention that a marginal increase in weight is beneficial - without some background - we are left to guess. It would also be useful if you define why - if the 20kg Rocna was almost flawless why you then chose (a more expensive, per kg, Spade) instead of a 25kg Rocna. It seem odd to reject a 'almost flawless' design, because it was, apparently too small - and then buy a totally different design.

One is left with the nagging suspicion you are not quite comparing apples with apples and if this is your basis for suggesting 'bigger is better' - it is valuable we have a better understanding of your decision process.

My understanding is you carry both anchors? and presumably use the 25kg Spade as your bower? with the almost flawless model, 20kg Rocna, kept as a spare (or to anchor in a 'V'?)

Jonathan

 

[Kukri]

Note that's 7 tons Thames Measurement, not displacement.

Elsewhere in the chapter, he writes that Thames measurement, rather than displacement, is the best measure to use in determining the size of ground tackle, because a heavy displacement boat with short ends will lie quiet whilst a light displacement boat with long ends will sheer about.

 

[Zing]

I wonder if the anchor companies have realised this and reduced their recommended sizes?

Recommended size is not a mathematical, incontrovertibly precise calculation. Safety factors and assumptions are a part of it and I choose bigger safety factors and more conservative assumptions. Don’t worry though. I won’t say you were complacent when I pull you off the reef when you drag.

 

[noelex]

I think the best advice for a cruising boat is to fit the largest anchor the boat and crew can comfortably manage. There are exceptions where this rule does not work, but it is at least a great starting point.

Anchor tables are worth consulting, but there are lots of anomalies. If you follow these, unfortunately you would select in most cases a much smaller Delta or Kobra anchor than when using the manufacturers’ tables for much higher performing anchors, which is obviously wrong.

If you can comfortably manage a larger anchor you will not have “wasted” your money, rather you will have an anchor that will have a higher maximum holding ability, greater security in substrates with lower holding, and greater security if forced to use a shorter scope than would be desirable for the circumstances. These are all valuable properties.

The above is sometimes disputed, but is really just common sense. A larger anchor has higher maximium holding ability than a smaller anchor (assuming the same design and material). Poorer substrates will produce a lower maximum holding ability, as will reducing the scope (an anchor’s maximium holding ability is not reached until a scope of 10:1 or higher). Thus a larger anchor may have the same maximum holding ability in a poorer substrate or at shorter scope, as a smaller anchor.

If you go significantly smaller than these recommended sizes, you will have to accept some compromises. Some of these are reguarly mentioned such as needing to deploy two anchors to increase the available holding in winds above 30 knots, or never anchoring overnight at less than 5:1. If I was using an aluminium Spade A80 (this anchor is recommended for a multihull less than 25 feet and less than 2 tons displacement) on a 38 foot catamaran with a 7 ton displacement, I would take the same type of precautions (in fact I would even be a little more conservative).

The approach of using very small anchors is not always a cheaper option. You will need to carry multiple anchors for different substrates, and if regularly deploying two anchors, more spare anchors will be needed to provide a back up.
I am not even sure there is an overall weight saving carrying two small anchors (plus spares) to substitute one larger anchor (plus spare), especially when the extra rodes are considered. The weight of two smaller anchors can be distributed better, but many boats only have practical storage for a second anchor in outside lockers that are near the ends of the boat so the differences are not great.

I would not suggest people follow my example either. My 68 kg anchor would not fit the definition of “comfortable to manage” on most 50 foot boats. I have been fortunate to be able to equip this boat with a large anchor winch and sturdy bow roller assembly. Storing the chain significantly back from the bow means that a very large anchor can be carried with less overall bow weight than would typical for a yacht this size.

However, many cruisers select an anchor that is slightly oversized to provide the benefits I have suggested in the third paragraph. Providing this fits within the definition of “comfortably manageable” I think this entirely sensible.

The benefits of even a small increase, for example from 20 to 25 kg, has been dismissed as negligible, but studies have shown (Professor Knox’s for example) that this change equates to a 25% increase in the anchor’s maximum holding ability (assuming the same design and material). Even the pessimistic data would suggest a around a 20% increase in the anchor’s maximum holding ability. In my view, this is a very worthwhile gain for only an extra 5 kg, but this is a decision that every boat owner must make for themselves.

Anyway just my view. I think it is important to offer a counterpoint to the frequent posts suggesting small anchors have no drawbacks or even by some magical properties provide better holding than larger models.

 

[Neeves]

The benefits of even a small increase, for example from 20 to 25 kg, has been dismissed as negligible, but studies have shown (Professor Knox’s for example) that this change equates to a 25% increase in the anchor’s maximum holding ability (assuming the same design and material). Even the pessimistic data would suggest a around a 20% increase in the anchor’s maximum holding ability. In my view, this is a very worthwhile gain for only an extra 5 kg, but this is a decision that every boat owner must make for themselves.


/QUOTE]

You do like to ignore what has been said. You also love to repeat your mantra with not an iota of substantiation - excluding your common sense.

John Knox used different rodes when he conducted some of his tests that formed the basis of the information you quote, from memory, wire, polyester and nylon. You cannot compare hold using different rodes.

John defined each rode in each of his experiments - you have the links - read the article carefully - as has been mentioned to you a number of times. Nothing gets more correct by constant repetition

But if you have any evidence for your comments, other than common sense, many of us, including GHA who likes a technical basis, would welcome the certainty.

Until then its all just fluff - constantly repeated based only on that common sense.

Jonathan

 

[JumbleDuck]

Recommended size is not a mathematical, incontrovertibly precise calculation. Safety factors and assumptions are a part of it and I choose bigger safety factors and more conservative assumptions. Don’t worry though. I won’t say you were complacent when I pull you off the reef when you drag.

How many sizes above recommended did you go? Why not more?

 

[Zing]

How many sizes above recommended did you go? Why not more?

1 size. It nearly doubled my safety factor. Two sizes wound nearly quadruple it. More would be better, but I have I feel enough and the next size is too heavy.

As to recommenced sizing, I do not believe the Lewmar CQR sizing is correct or comparable to others. And you are wrong to think it can be relied on in my view. There is no standard or openness in respect of how calculation are done. The sizing by Rocna and others has a greater safety factor built in already as evidenced by their greater performance on a like for like recommended size.