Anchors - Bigger is Better ?

[Kettlewell]

As an aside, whatever else you think about Rocna, there's some decent stuff in their knowledge base, including this table on chain sizes and strengths.

[JonJo]

Don,

Your views are similar to mine, I've not heard of many chains breaking (actually cannot think of any but my memory is not perfect). But we have had a plethora of posts about the best shackles in the world, which I'm thinking are far better than the chains - so why the heavy promotion if the weaker link (the chain) is considered good enough.

Just wondered about the justification for spruiking the shackle and thought there must be something I'd missed.

[sailorboy1]

Originally Posted by JonJo

Don,

Your views are similar to mine, I've not heard of many chains breaking (actually cannot think of any but my memory is not perfect). But we have had a plethora of posts about the best shackles in the world, which I'm thinking are far better than the chains - so why the heavy promotion if the weaker link (the chain) is considered good enough.

Just wondered about the justification for spruiking the shackle and thought there must be something I'd missed.

When I got my oversize anchor (that I had to use 2 shackles to connect the chain to because the 5/16" was too small) I went though all the "this is weaker" stuff. I even went the swivel shackle thing. In the end I stopped worrying about the shackles etc because I figured it just wasn't going to matter except that the stuff would still be attached to the anchor while my boat was drifting away because something else gave out.

[JonJo]

Kettlewell,

Nice, or apt, link.

There was also an interesting article in Jan, 2013 YM on chain and a follow up in the April edition (which does not entirely agree with Peter Smith - but Smith has a NZ/Oz/American perspective and YM a much more narrow UK view).

YM's conclusion was that much G30 chain is almost as good as G40 and that the cost of G40 is simply not justified. Moreover G30 seemed to be better galvanised than G40. YM and 2 suppliers (who both had some financial interest as they sell chain) were also very supportive of Chinese chain - the quality of which they, the suppliers and YM, found very acceptable.

[JonJo]

Originally Posted by Don L

When I got my oversize anchor (that I had to use 2 shackles to connect the chain to because the 5/16" was too small) I went though all the "this is weaker" stuff. I even went the swivel shackle thing. In the end I stopped worrying about the shackles etc because I figured it just wasn't going to matter except that the stuff would still be attached to the anchor while my boat was drifting away because something else gave out.

You made the comment in the earlier post that something on the yacht would break before the chain, a view with which I agree. Having only glanced' at windlass and cleat fittings (particular the backing plates) I suspect you will break something (important) before the chain or shackles break - at least on most volume production mono yachts (which is what most people own).

I'd be suggesting new, bigger, backing plates for cleats etc prior (or as well as) the 'Hummer' of shackles.

[Kettlewell]

YM's conclusion was that much G30 chain is almost as good as G40 and that the cost of G40 is simply not justified. Moreover G30 seemed to be better galvanised than G40.

Any link to that article? The main problem is that apparently what is called Proof Coil chain over here (G30) has slightly longer links than G40 stuff, and most of the windlasses we see are designed for G40 or G70 sizes. I have thought myself that Proof Coil chain I have used has better galvanizing that seems to last longer, but others on this forum have disputed that.

[JonJo]

I do not have a link, nor a pdf, but the article was written by Vyv Cox and there might be something here:

Cox Engineering - Home

I suspect someone might have a link later.

[Kettlewell]

This is the page on the Cox website. Not sure I agree with the idea that the made in China chain is just as good because of this test. His theory was that the G30 was the equal of the G40 because that was the steel that is most readily available in China. Have no idea if that is true, but I don't get a feeling of confidence if something isn't what it says it is. What happens when a ship load of G40 material isn't available?

[DumnMad]

There's China & there's China just as there's genuine & counterfeit.

Stretch means chain gives more warning than shackles after overloading.

[Cotemar]

The objective is to setup your ground tackle, strong, stronger, strongest

1) Anchor strongest ASTM 514 (High tensile steel), yield strength 690 MPa min.

2) Shackle stronger, Crosby 7/16, G-209A Shackle (WLL) is 5333 lbs. or 2.6 tons

3) Chain strong, 5/16 High Tensile G4 Chain. (WLL) is 3900 lbs.

WLL (Working Load Limit)

[JonJo]

Kettlewell,

I agree with you, but there were 2 UK chain importers apparently agreeing in the follow up in April. What it needs is another set of random tests in the UK and a parallel series in America.

Cotemar

Maybe you can advise which other anchors are ASTM 514, I only know of Manson's Supreme and Boss and Anchor Right's Excel. Most anchor manufacturers simply do not specify the steel they use, so you have definition of chain, definition of shackle but only have definition of your steel anchor if you buy from Manson or Anchor Right. Otherwise you are exposed. Seems contradictory to worry about chain and shackle and not worry about your anchor.

[Cotemar]

The objective is to setup your ground tackle, strong, stronger, strongest

Nothing contradictory. Just follow the numbers.

All the new gen. anchors are (High tensile steel), yield strength 690 MPa min.

[JonJo]

Originally Posted by Cotemar

The objective is to setup your ground tackle, strong, stronger, strongest

Nothing contradictory. Just follow the numbers.

All the new gen. anchors are (High tensile steel), yield strength 690 MPa min.

Maybe it depends on your definition of new gen anchors but possibly you can list with references to use of ASTM 514

Manson quote usage, Anchor Right quote usage, I struggle thereafter but maybe I am either out of date or missed the detail.

I would love to be enlightened.

[downunder]

Originally Posted by Cotemar

The objective is to setup your ground tackle, strong, stronger, strongest

Nothing contradictory. Just follow the numbers.

All the new gen. anchors are (High tensile steel), yield strength 690 MPa min.

It was my understanding that ROCNA now have gone away from using Bis-alloy steel yield strength 690mpa to what they consider fit for purpose and most likely not 690mpa. I also recall they were arguing less was OK but they have since removed that discussion and do not post the Yield strength of the steel used in ROCNA's manufacture anymore..

Whilst some of new generation anchors use 690mpa steel I do not think it is correct to say all do.

Please convince me ROCNA are now days using 690Mpa steel shanks.

[noelex 77]

Originally Posted by JonJo

The advantage of the 2 x 20kg anchors is that we can use 2 x 8mm chain (and the fancy shackles). The disadvantage of the 10mm chain is more weight in the bow (the spare 8mm chain can be stored amidships) and you need a new gypsy, maybe new winch.
.

I don't believe 2x8mm chain (with two anchors) is as strong as 1x10mm chain (with one anchor). The problem is that it is impossible to even out the loads. Particularly when snatch loads are imposed these tend to carried mainly by one rode.
With two anchors I would not advise going below the recommended chain size for your size / displacement boat. This means you end up with double the weight of chain to routinely deploy two anchors.
An extra 75 m length of 10mm chain weighs 176kg (380lb) (even 8 mm chain weighs over 100Kg (220lb)
The anchors are also typically heavier in a two anchor set up (although their contribution is minor).

Yes you can store some of this weight amidships with a two anchor set up, if you don't mind physically carrying the weight to the bow, perhaps at 3am as squall goes through he anchorage.

If the chain is to used regularly, you also need a place amidships to store chain that is likely to be dirty and smelly. The amidships locker will not commonly be self draining.