What Size Anchor Chain ? (Again!)

[colemj]

Originally Posted by Andrew Troup

Heavy chain makes GREAT internal ballast.

That would be a large negative for a lot of us.

Mark

[DumnMad]

Just read this thread. Klem is dead right. Storms of 60knots produce 4 times the load that a 35knot gale does. You wouldn't sleep much at anchor during a storm. Most coastal cruisers avoid storms so may not need the snubber but many cruisers do not have a marina to hide in.
Those who would trust a catenary for shock absorption during a storm need to test their theories in an anchorage where dragging will do no harm.

[GMac]

Originally Posted by hpeer

For what it is worth Raya has a gear sizing chart on their site.

Off hand it looks like they are suggesting 1/2"

Page d'accueil

That's a Rocna site and Rocna info. It has nothing to do with Raya.

[GMac]

Originally Posted by klem

The best source of information on the subject is at the website I have listed below. Peter Smith (most people know him from Rocna) shows simulations of the effects of catenary and how it does not play a significant role in high winds.
Catenary & Scope In Anchor Rode: Anchor Systems For Small Boats

That is son Craig not Peter. If Peter believed the small chain theory he wouldn't be carrying the big chain he does. He could be carrying a 5/16" chain of the same strength as the 1/2" he is actually using........ but he's not.

The small chain big anchor theory is one of Craigs as he is a great believer in what Steve Dashew says. That's fine as long as you realise Steves boats wouldn't put anything like the stress nor strains on an anchoring system an average boat would. Steves boats are very lite weight no windage skinny pencils, the average boat isn't. He also has an anchor similar in size to the average dingy. Not the best comparison to use really but does make a nice talking point if you want a specific end result.

Look around and if the tiny chain huge anchor theory was the best why does next to no one, including many horrendously experienced boaters, use it?

It's an interesting discussion. If you like small chains that's fine but be prepared to have your anchor do ALL the work. Personally I'd far prefer a balanced system, the one that has proven the test of time in real life use rather than the test of a calculator.

We see and get told this small chain to big anchor theory a lot, the joys of the interweb and the 'have you seen this?' ability it has. Interestingly no one who has talked it up has actually gone that way.

[noelex 77]

Originally Posted by GMac

That is son Craig not Peter. If Peter believed the small chain theory he wouldn't be carrying the big chain he does. He could be carrying a 5/16" chain of the same strength as the 1/2" he is actually using........ but he's not.

This is an old thread, but it still raises interesting points.

Its not as light as Steve would advocate, but I would still describe 1/2 inch chain on a 27 ton(60,000 lb) boat that cruses arctic waters, as small chain.(for the boats displacement)

Originally Posted by GMac

He also has an anchor similar in size to the average dingy.

Steves smallest FPB boat (62 feet) uses a 240 lb (110 Kg) Rocna. You must have a big dingy anchor GMac.

[colemj]

It is important to separate the idea of using very small chain from the idea of not oversizing the chain.

There are a lot of discussions on this board around ideas like 10mm all chain on 30' boats with 40kg anchors and how anything less is taking your life in your hands. Most of the discussions here center around 8mm G4 vs 10mm G3 and the perceived advantage of the heavier weight - even the advantage of BBB over all of them.

In almost every case, the argument is not about undersizing to a very small chain size - rather it is an argument about whether to oversize or not. That is very different than the Dashew argument.

Mark

[bruce smith]

On a side note, hardened chain , G4, rusts much faster than " ordinary " proof coil chain.
If one is on a weight sensitive multi hull, saving weight is more important.
If one is sailing a budget monohull, having your galvanizing last much longer is important.
I made the G4 mistake once, and will be sticking with heavier ordinary chain for my budget monohull.

[colemj]

Originally Posted by bruce smith

On a side note, hardened chain , G4, rusts much faster than " ordinary " proof coil chain.
If one is on a weight sensitive multi hull, saving weight is more important.
If one is sailing a budget monohull, having your galvanizing last much longer is important.
I made the G4 mistake once, and will be sticking with heavier ordinary chain for my budget monohull.

If you bought ACCO/Peerless chain, then I agree with you. Ours rusted completely in one year and we met 12 other boats in Grenada replacing their rusted ACCO chains that were less than one year old.

ACCO has serious quality issues with their chain. ACCO/Peerless agreed to replace ours when presented with the evidence and pressured by their reseller, but then went AWOL when it actually came to sending us the chain and simply stopped responding to all further attempts at communication.

During all this, I did discover that when Peerless bought ACCO, they changed the galvanization process and moved the manufacturing to a different facility in a different state.

Our Maggi chain, however, is now two years old and has no rust whatsoever on it.

Mark

[Bash]

Originally Posted by GMac

The small chain big anchor theory is one of Craigs as he is a great believer in what Steve Dashew says.

Actually, the small-chain-big-anchor theory was Craig's because he had a vested interest in selling you a big anchor.

Amazing how many of our forum members bought the theory hook, line and.....

Ahem.

[bruce smith]

Thanks Colemj, Good to know about the acco peerless brand . Mine was from Fisheries in Seattle. dunno the brand.
But hardened steel will rust faster than mild steel , that is just what it does.
A hand saw or chisel left outside will rust faster than a screwdriver or a shovel.
On a chart, the hardened chain looks irresistible.
Scrape it over a rock or a patch of coral overnight, your goose is cooked.

[noelex 77]

Originally Posted by Bash

Actually, the small-chain-big-anchor theory was Craig's because he had a vested interest in selling you a big anchor.

Amazing how many of our forum members bought the theory hook, line and.....

Ahem.

With respect Bash I don't think the "big anchor small chain theory" can be be dismissed as a marketing exexerse. The greatest proponent is Steve Dashew who has no financial incentive.

The theory has two great things going for it.

1. The numbers.
If you take my boat ( a 47 foot monohull crusing boat) I could have 100m 12mm chain and say a 25Kg anchor or a total weight of about 400kg. or 100m of 10mm G7 and a 100 Kg anchor for a total weight of less, at 330kg.
I think most people would vote for the lighter chain and heavier anchor having the higher holding power.

2. Anchor/chain observations
Dive and look at the chain in in 40+ knots of wind. It's bar tight no matter the weight.

So much for the theory.
Well I have put the theory into practice and changed from 12mm to 10mm chain ( with not change in anchor size).
The verdict well I am not sure.
The lighter chain requires quite a different setting technique to the heavier chain. I dragged my Rocna for the first time ever in only moderately strong winds (40k average).
Since then with some change in technique I am back to getting very good sets with lighter chain, but the wind has only been light. With the stronger winter winds here I might be back to ordering some 12mm chain. Time will tell.

Note this is without changing anchor size. Maybe someone else can change both anchor and chain (keeping the total weight the same or maybe a bit less because the anchor weight is more detrimental to trim and windlass) and tell us if the light chain /heavy anchor theory is correct. I would be very surprised if saving weight in the rode and putting it into the anchor is not a superior option.

[cfarrar]

To say that Peter Smith and Steve Dashew recommend "small" chain is not accurate. They argue for strong chain, saving weight over inferior grade chain of the same strength, which allows for a bigger anchor, all else being equal. It's common sense, really. If you want to see how this pays off in practice, just search on Nick's (SV Jedi) threads concerning hurricane Ivan in Grenada.

[DumnMad]

Its compromise to suit your cruising lifestyle. Generally with hot dip galv the bulkier the metal the thicker the layer that solidifies onto it. Living on anchor a lot then go to heavier chain.

[klem]

I get the impression that some people may have interpreted the statements of myself and a few others to mean that heavy chain is worse in terms of holding power which is not true, all we (I hope that the others don't mind) were arguing is that heavier chain does not significantly increase the holding power in extreme situations where it really matters. Even on really heavy boats, the weight of anchoring gear has an effect on performance so most people try to keep their gear relatively light. As in the example laid out by Neolex, you will get more holding power for the same weight package going with a bigger anchor and lighter chain rather than a lighter anchor and bigger chain. If you feel that your boat can handle the weight of both a big anchor and big chain, then go for it but in my opinion, this is less than optimal on most boats.

It doesn't really matter whether it was Craig or Peter who was the commercial vendor promoting this style of gear selection, I am sorry if I got it wrong. This is certainly not a theory brought around by them, there are real cruisers who have been anchoring quite successfully this way for quite some time. On this board, there are a few, many of us are participating in this thread.

The argument really hinges on whether there is any significant chain catenary left in a real storm where the anchor's ultimate holding power is tested. The theory says that there is basically none and this is backed up by real world observations. I have seen 1" stud link chain pulled out bar tight in what I would consider bad but not awful conditions. Needless to say, the boat dragged a bit each time a wave hit it because there was no give. For 9 years, I worked aboard a boat that used 3/4" chain as its working chain and I saw that stretched out tight many times. On moorings, the same problems exist and it is the reason why Hazelett rodes were developed which have been extremely successful.

Personally, I like the balance that G40 gives. It is close to twice as strong as G30 but it doesn't require special ends links and it is very easy to acquire. If you want to use really heavy chain, go for it, just please use a good snubber and a big anchor if you happen to anchor upwind of me when weather will be coming through.

[GMac]

I think you will find the trouble Acco had with the rusty chain was with their 'premium imported' chain not the one they make. Acco does make good stuff and I'd very happily use it on my own boat and I do know chain very very well.

Which gives a nice segway into this bit.

Grade 40, or Grade M it's new name not being used by many, is not twice as strong as a Grade 30 (L). It's close as 25% stronger. A 10mm G30 will bust at 5000kg, a Grade 40 at 6400kg, minimums from reputable manufacturers only obviously.

What you have fallen for is marketing and a nice bit done very well, which we can prove by reading this thread

Why many think it is twice is strong is due to reading WLL's but not understanding Design Margins. So a chain 101 again.

WLL is the Working load limit. This is the load that shouldn't be exceeded and the chain manufacturer (the respectable ons at least) has designed and tested it to. The WLL is usually 25% of the minimum break load. So the two 10mm's (roughly 3/8", I'm in a metric country) have WLL's of 1250 and 1600kg respectively.

Proof Coil. This means nothing at all but is used a lot to bluff punters into thinking 'Whoo! this must be good, here have my money'. The term came about many years back when there wasn't much choice to tell the punters the chain had been tested to some degree. So the terms 'Proof Coil' or 'Proof Tested' mean nothing unless it is attached to a number, that number is what you need know. Why I hear you ask..

Example - A length of 10mm chain. I'm holding one end and cheeky Noelex is on the other. We both lean back pulling the chain as hard as we can. Bingo, we can now officially without lieing nor breaking laws call that length of chain 'Proof tested'. But hang on a minute, my life is worth more than what Gmac and Noelex can pull, all say 100kg of it. That same length of 10mm chain in the Maggi or Acco factory can leave also being called 'Proof tested' but both of those would have loaded that chain to 3200kg, at least if talking a G40. So we have two 10mm chains both legally being able to be called 'Proof Tested'. Which one would you buy and why? If I hadn't listed the respective Proof load numbers would you know there was a significant difference? Next time you go chain shopping and the sales dude says' 'All good mate, she's 'Proof Tested'', are you going to probably confuse them silly (as most wouldn't have the faintest idea) by replying 'So what was the Proof load then?'

It's common to see chains promoted as Proof Tested as a sales pitch but if you have seen the number of numbers I have out of eastern manufacturers you'll find many, not all, can legally call their chains Proof Tested. But on that 10mm again the Proof load is often only 1500 to 1800kg, meaning WLL's of only 750-900kg. We've seen some 10mm as low as 1000kg so only a 500kg WLL and some just aren't tested at all.

Design Margin. This is basically the safety margin between the WLL and Break load. The industry standard and most Standards (the many ISO like ones and others) have the Design margin at 4:1 meaning the break load is 4 times more than the WLL. But in the very odd place that does vary.

Now back to the G30 V G40 thing. What has tripped up Klen and many many many others is in the US they run a lot smaller design margin on the G40 (some is G43) than the rest of the world. They also tend to hide the break loads so all you see is the WLL. People see the WLL on the G30 and then the G40 and they are sort of distorted as they aren't working off the same base. This does show the US G40 as being masses stronger than the G30's, which they do use a 4:1 margin on.

That doesn't apply outside of the US where everyone uses 4:1 but there has been one or 2 popping up running the US system as it does make the chain look spectacular in strength. Marketing is what that is about, nothing more.

There are one or two other chains with design margins that aren't 4:1. Maggi AQUA7 for example, that has a 5:1 design margin meaning the break load is 5 times the WLL.

Stand by while I fire up the magic box and I'll post some real life number for your pondering pleasure.