Does a New Generation anchor need to be oversized?

I though the OP and Crina had it dead on. New anchors are better. I had a Delta.

Some cruisers like to go massive. That's OK for them. Much depends on how often and where you anchor. If you expect to sit out a tropical storm on questionable holding ground, monster is good. If you anchor in very soft mud (Chesapeake Bay) and have strong thunderstorms, big is good, although standard Rocna sizing is conservative.

It's not about the money. Really. It's not about the weight, unless you carry a lot of over wieght chain.

Then there is the internet fear factor.

I've done a lot of testing for articles and a book. Perhaps the clearest lesson is that few anchors drag because they were overwhemed in good holding ground. There was always another factor, and that other factor reduced holding by 3-10 times. A 20-30% larger anchor won't solve that.
  • Trash. The anchor fouled on a stick or shell. Or perhaps the chain fouled, preventing digging.
  • Soft spot.
  • Weeds. The anchor caught on weeds, but broke loose when it really blew.
  • Underlying hardpan. Very hard to detect, even with power setting.
  • Yawing or hobby horsing.
  • Stupidly short scope. Rare.
Often the error band on anchor testing is +/- 60%. In that case, you move to more consistant bottom for testing. But the cruiser does not know this. I have 4 favorite testing areas, where I know the bottom is consistent. I also have places with know problems (rock, hardpan etc.).

Unless the anchor is tragically undersized, it is not the reason you are dragging. My 2-pound Guardian will reliably hold 500 pounds (the wind load of a 38-foot boat in 30-35 knots) in good sand. A conventionally sized Rocna or Manson will hold well into huricane force.

But you can argue it to death, which I'm sure we will. How safe is safe? What are your anchoring bottoms like? How much care do you expend? How owten do you anchor? Do you anchor out in severe storms (winds over 50 knots, not just a lot of rain)? But rememmber, if you anchored on hardpan, an extra 15 pounds isn't going to make an important difference.
 
We have the correct size anchor for the weight of boat and size as per the Spade selection chart. We always anchor and never go in to a marinas whilst in the Caribbean. There are just two exception to this, a short trip to a marina whilst we transited the Panama Canal as crew and a month in Colombia whilst we did some traveling. Other than that we have spent the last 2.5 years as liveaboards.
In my experience of seeing lots of people mess up anchoring most fail to set their anchor by simply not deploying enough chain. This is nothing to do with NG anchors or old types. We see so many sailors deploy a small amount of chain then reverse. If it doesnt drag, they let some more out! If it drags they pull it up and try somewhere else! I once watched a Yank do this ten times!
A couple of days ago a 50ft cat tried to anchor close to us. He did everything correctly but his anchor wouldnt set. He had a Delta.
He eventually anchored further away. I spoke to him later in the day, rescuing his dinghy. He said I must have the only decent holding in the bay Ias he hadn't managed to get his anchor to set! We have anchored here numerous times and never failed to get the Spade to set in the grassy/ sand bottom. NG anchors make a big difference but technique is also important
 
Most anchors drag because they were not properly set or the wrong choice of seabed or the bottom was foul (old steel cables, etc) Anchoring is more than just throwing that hunk of metal over the side and going to the pub. Most failures are definitely operator errors. We are always very fussy when we "set" the hook and often it has taken several attempts to achieve that. We recently rode out a F8 in the Waddenzee (no shelter from the wind) in muddy sand and 4kts of tidal current on an old CQR 35lbs. My wife, newer to this game, backed us in with such enthusiasm that I nearly went over the bow. We slept well that night. Our friend dragged on a 20kg Spade on the same bottom in a F6; he was not impressed with his new hook. At some point we will all end up dragging, question is how do we deal with it when it happens. We always prepare to cut and run, buoy and leave the anchor if necessary and always have an escape route planned. Most anchors work fine, most of the time.
 
Hi Norman ,
I said weekend sailors not weekend winds . its more then likely a guy who off for the week end and its forecaster to blow 30 plus would end up returning back to the marina for the night or even not leave the marina at all ,
the days when I was based in a marina very few people would leave if it was over 25 kts a good day sailing let alone think about anchoring
 
Is the extra peace of mind that you'd gain by having gone a size larger worth £500 is the question but remember if you're swapping a 20kg Delta for a 20kg Spade you're roughly doubling your ultimate holding power and I think the evidence suggests that with a Rocna or Spade (as well as some other NG anchors) you can go with the recommended size. I've just moved from 20lb (9kg) non-genuine CQR to a 9kg Knox for 26ft 3 tons. Yours would come well within the parameters for an 18kg Knox. ..

Edit - An aside but do you have an anchor alarm of sorts, I just started using anchor watch lite, a free Android app, which does give a bit of extra peace of mind...
 
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Laminar Flow said:
Most anchors drag because they were not properly set or the wrong choice of seabed or the bottom was foul (old steel cables, etc) Anchoring is more than just throwing that hunk of metal over the side and going to the pub. Most failures are definitely operator errors. We are always very fussy when we "set" the hook and often it has taken several attempts to achieve that. We recently rode out a F8 in the Waddenzee (no shelter from the wind) in muddy sand and 4kts of tidal current on an old CQR 35lbs. My wife, newer to this game, backed us in with such enthusiasm that I nearly went over the bow. We slept well that night. Our friend dragged on a 20kg Spade on the same bottom in a F6; he was not impressed with his new hook. At some point we will all end up dragging, question is how do we deal with it when it happens. We always prepare to cut and run, buoy and leave the anchor if necessary and always have an escape route planned. Most anchors work fine, most of the time.
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your right most do drag because they don't set their anchors , we see it time and time again . which is the biggest problem and not so much the anchor or the sea bottom.
but the OP want to be able to be safe what ever happen and if your a cruiser as we are we don't always get to chose a good sandy bottom after a 36 hour sail arriving in the middle of the night we have to take what ever we find and if the wind happen to be blowing 20 kts or 40 kts we have to deal with it , so having good ground gear can only help .
 
Seems to me that Prof.Knox's article is all about the varying holding power of anchor types whether holding firm or dragging ,and the effect of increase in anchor weight and doesn't assist in anchor selection for a particular hull .
Ultimately the snatch dynamic load created by the wave/swell condition , the keel form ,the current,the lying direction will produce maximum force on the rode so the displacement has to be considered.It won't change the performance of the anchor but you have to start by considering the imposed loads in the conditions that you envisage encountering.It's a poor start if the manufacturer doesn't qualify his tables by stating the wind range assumed and the displacement .I am often shocked by the exposed conditions in which some cruisers are driven to anchor in ,simply because locally the only alternative is to head back to sea.
 
When I dumped the CQR and replaced it with a Rocna, I used the sizing chart on the website, which told me I needed a 20 kg anchor. To date, it’s let me down once, in a force 8 in Sardinia when it turns out I anchored in a weed bed. Held fine until the wind really got up.
Since then, it’s held just fine in winds up to 60 knots +. I’d stick to the recommendations made by the makers: they’re trying to sell you their product, they’d like you to buy the more expensive one but don’t recommend it. Think why that is: it’s because they want the product to work properly...
 
bluerm166 said:
Seems to me that Prof.Knox's article is all about the varying holding power of anchor types whether holding firm or dragging ,and the effect of increase in anchor weight and doesn't assist in anchor selection for a particular hull .
Ultimately the snatch dynamic load created by the wave/swell condition , the keel form ,the current,the lying direction will produce maximum force on the rode so the displacement has to be considered.It won't change the performance of the anchor but you have to start by considering the imposed loads in the conditions that you envisage encountering.It's a poor start if the manufacturer doesn't qualify his tables by stating the wind range assumed and the displacement .I am often shocked by the exposed conditions in which some cruisers are driven to anchor in ,simply because locally the only alternative is to head back to sea.
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Both the French classification society and the Germanic Lloyd (and I'm sure the British and American ones do too) provide formulas to calculate the size of anchors based on displacement, size and depth of hull as well as volume of superstructures. The results are very conservative and on the cautious side.

As a rule of thumb, a plow will hold minimum 200 times its weight and maximum 700 times its weight or, on average, say 500x. Providing it has properly set, of course.

I agree that it would be better if manufactures were to provide the expected holding capabilities of their products, rather than suggested boat sizes for determining anchor size. Wind loads vary widely with boat type and rig and should be individually considered and calculated.

I have never understood the arguments for different anchor sizes for weekend sailors versus cruising sailors. When I anchor, I want the boat to stay put - period.

Just to add before everyone goes crazy: SWL for 8mm DIN 766 Chain is 6.3t, Test load is 12.6t, and Breaking load is 25t.
 
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Laminar Flow said:
I have never understood the arguments for different anchor sizes for weekend sailors versus cruising sailors. When I anchor, I want the boat to stay put - period.
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its very straight forward , in the days when I was a weekend sailor using the boat at weekend or during the week say for a over night stop over ,
I wouldn't be looking at going out to anchor anywhere if the forecaster was for a hard blow, if I did go out sailing it be for a day sail and returning back to my berth so there was no need to have a large then needed anchor, I was never going to get caught out .
as a cruiser we don't have a marina so once we leave out winter berth we have to deal with what ever weather we have ,
in my case a slightly bigger anchor and 10 mm chain we found works for us on a 13 ton boat .
 
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sizing up an anchor isn't that straight forward if you look at Rocna size for my 42 foot boat 13 ton there no fix anchor size .
39 foot 10ton =20 kg 18 ton =25 kg
next size is 46 foot 13 ton =25 kg
we fall in between 39 and 42 foot so I rather have the 25kg then the small one of 20 kg
same apply to chain .
 
Laminar Flow said:
I have never understood the arguments for different anchor sizes for weekend sailors versus cruising sailors. When I anchor, I want the boat to stay put - period.
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If bad weather is forecast (such as the current UK system), most weekend sailors are likely to stay in their marina berth or on their mooring, and pick another weekend to enjoy an anchorage. This is only sensible.

Boats are always a compromise and it is sensible to pick equipment to suit the expected requirements and operating conditions. It would be great if every vessel had state of the art anchoring equipment (especially if they choose to anchor in front of our boat :)), but this is not likely to happen.
 
sailaboutvic said:
its very straight forward , in the days when I was a weekend sailor using the boat at weekend or during the week say for a over night stop over ,
I wouldn't be looking at going out to anchor anywhere if the forecaster was for a hard blow, if I did go out sailing it be for a day sail and returning back to my berth so there was no need to have a large then needed anchor, I was never going to get caught out .
as a cruiser we don't have a marina so once we leave out winter berth we have to deal with what ever weather we have ,
in my case a slightly bigger anchor and 10 mm chain we found works for us on a 13 ton boat .
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That is assuming the weather guys get it right, which even today is not always the case; ask me about last summer, sailing between Guernsey and Brehat. There is a wide span between " F4-5, F6, later" and "gusting F 10 imminent." Happens at night too, I've heard, when you're swinging on you're weekender lunch hook.
 
Let me start by looking at the phurphy of chain.

When you are wondering if your anchor will hold the wind, measured at the masthead, will be 30 knots of more. If you are using the recommended sized chain it will be as straight as a billiard queue, if you have used the next size up it will appear straight in gusts over, say, 33 knots. If you are not using a decent snubber you will experience snatch loads that will become increasingly catastrophic and your wife will be ringing the lawyer preparatory for a divorce.

The snubber will save the day, and the wife (and the children will not be bawling their eyes out). If the snubber is the saving grace the use of heavy chain is a bit of a waste - as a snubber is considerably cheaper and weighs less. A snubber will also continue to work to high windspeed - IF it is long enough.

If anchors of the recommended size were prone to dragging the anchor makers would have altered their recommendations. Good news does not travel well but anchors with a propensity to drag when sized correctly would be all over forum like a corona virus in a cruise ship. The spread sheets for the newer anchors have been the same, for Rocna, since around 2006 and anchors introduced since then - the spreadsheets have remained unchanged.

Of course with people recommending go oversized, why would the anchor makers need to change - they have unwitting salesmen out there.

I'm suspicious of the comment that all long term cruisers use oversized anchors - this is not my experience as many use anchors that look of the recommended size. I'd value any statistics to prove the comment. What I do find is that long term cruisers carry a quiver of anchors which they are not afraid to use, swapping anchors for the seabed and/or setting 2 anchors in a 'V'. Long term cruisers use shore lines much more frequently than would any 'weekend' sailor.

I have tested a Mantus a number of times - it has the hold slightly better than a similarly sized Delta. I have made enough tests to be confident in the results. At least 2 other people (or groups of people) have also tested a Mantus and have similar views. Noelex provides an excellent example - he replaced a 50kg Rocna with a 50kg Mantus on his previous yacht and was unaware of the hold characteristics of the Mantus. He thought it had the hold of there same sized Rocnas. He bought the Mantus without knowledge of its hold characteristics. The anchor recommended by Rocna for his previous, and current, yacht is 33kg. Noelex has been spruiking the merits of the Mantus ever since.

To me this suggests the hold of a Delta is good enough for the yachts for which it is recommended - its weakness is - it is difficult to set reliably and if it drags - it does not or seldom resets. Too many people have used a Delta (and still use it) without issue and prior to 2006 - there was nothing else (except a poorly marketed Spade and Fortress).

Returning to Noelex experiences - the builder of Noelex 'expedition' yacht makes the comment, I think in a video, that they customise yachts to the clients requirements (and Noelex in his thread on the build supports this). The builder specifically mention that Noelex wanted to be able to carry an oversized anchor (he high lit this comment in that he did not define other special requirements, like rig, heater, engine etc etc - he specifically mentioned the anchor. This suggests to me that Noelex was an exception and most of the other expedition yachts built by the builder have conventionally sized anchors - slightly contradicting the idea 'all long term cruisers carry big anchors'. (Frankly I'd rather twin bow rollers and 2 anchors, of different styles).

The fact that people use large anchors with success is not proof they are needed - it simply proves people have that extra money (and maybe have succumbed to the fear - and that comment, who wishes they had a smaller anchor when the wind blows 50 knots).

Our experience is we chose an anchor by design and that had been tested. Our Spade, our Excel both have a hold in a decent seabed of 2,000kg. The highest tension we have ever recoded, I measure these things, is 650kg. We have a Fortress with a hold slightly less and another Fortress with a hold slightly more. We use 30m snubbers and 6mm chain. We are a high windage catamaran. Forecasts are good and we try to find shelter when, genuine, Storms are forecast. If the chips are down, we deploy another anchor in a 'V' - what else are you doing when a storm is forecast?

There is a suggestion a bigger anchor will set where a smaller one might be defeated - I have seen no evidence of this. What I have seen is that a larger anchor cannot be set so deeply as a smaller one, it leaves much of the anchor exposed, so you loose the vertical hold (the vertical 'fluke') of the shank (as it is not buried) and the anchor is more susceptible to movement through veering. I also note the heel of the larger anchor often lines exposed - and in a change of tide, or wind (when waiting for the Storm to develop) the chain can get under the heel (or stock) and trip the anchor (which is why we have small Fortress - we can set and bury it)

Jonathan

My apologies, Bestaever make mention of plenty of custom features - blame my selective memory


Check here

KM YachtbuildersZenith • KM Yachtbuilders

and read the first paragraph of 'Zenith'
 
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Well I hope I correctly understood this thread and the dozens of others...because I just snapped up a 20kg rocna on Amazon for 168 quid.....classed as used acceptable which usually means sent back because of scratch or lost by courier...

So that is my anchor research over.....

Now what to do with my cqr...
 
pandos said:
Well I hope I correctly understood this thread and the dozens of others...because I just snapped up a 20kg rocna on Amazon for 168 quid.....classed as used acceptable which usually means sent back because of scratch or lost by courier...

So that is my anchor research over.....

Now what to do with my cqr...
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Aah. - you have just bought a bendy one from before they got the spec right. It will hold very well - even when the wind changes as the chain follow.
 
pandos said:
Well I hope I correctly understood this thread and the dozens of others...because I just snapped up a 20kg rocna on Amazon for 168 quid.....classed as used acceptable which usually means sent back because of scratch or lost by courier...

So that is my anchor research over.....

Now what to do with my cqr...
Click to expand...

Sell it on eBay or Amazon? :)
 
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