Question: I read with interest your discussion of anchor chain and shackles on your site. Are you referring to Crosby G209 shackles or G209A? We are using 3/8” HT chain and a S S140 on a Cambria 44.
Answer: When using high tensile chain we recommend using the Crosby 209A (the ‘A’ stands for ‘Alloy’) shackle since, size for size, the plain 209 shackles are weaker than Acco G40 high tensile chain.
Looking at your case, Acco 3/8” G40 chain has a safe working load (SWL) of 5400lb and the 209A 7/16” shackle matches well with a SWL of about 5800 lb. (We have found that you can go one size up in Crosby shackles from the chain size without fit problems, but beware since the sizes quoted in both chain and shackles are nominal, and actual dimensions vary from that; for example, the shackle pin is substantially thicker. You can check all of this out in minute detail at the Acco and Crosby sites.)
Note that if you are going to use Acco G70, with a SWL of 6600 lb in the 3/8” size, you will need an oversize link in each end to allow you to go up two sizes on the 209A shackle to get the same strength in the shackle as the chain.
By the way, be very careful about what really is, and more importantly, is not, HT chain. The words ‘High Tensile’ cover a multitude of sins in chain. We use Acco G40 and G70 as our basis of comparison. As we have said before, the key rode safety is to make sure that the chain and shackle manufacturer are willing to provide a proof certificate at the advertised SWL.
{ 5 comments… read them below or add one }
I got 400 feet of HT from Acco and had them add a large link at both ends. This way I use a over size shackle to ensure no loss of strength.
Charlie
The Shackles I use are “Crosby” the pin in these shackles are painted red and have the work load stamped right on it
Regarding the Crosby G209A shackles. I have been using them for some time and like that they are about 2x stronger than the regular galvanized shackles and well matched to HT anchor chain.
I notice that after a while the pin starts rusting. I assume that’s because it isn’t galvanized. At what point to you replace the shackles?
In the picture at the start of this article, I notice you use two shackles between the chain and the anchor. I have only been using one. Why two?
Thanks, Bob
Hi Bob,
A little surface rust is no problem at all. Replace when there is actual pitting or reduction in the “wire size” (chain talk for the diameter of the stock the chain or shackle is made from).
There are two shackles because neither the hole in the anchor stock or the size of the 7/16″ G40 chain link are large enough to take the body of the shackle.
Next time we order chain, we will get a way oversize link put in at the end that will take the shackle body. (When we ordered this chain we still had the CQR that had an integrated shackle with a large hole permanently attached to it).
In a perfect world, the hole in the SPADE anchor stock would be larger so that the bow of the shackle could pivot through it. However, the two shackles are not a problem because neither is long enough to exert excessive strain on its own pin threads in the case of an off axis pull.
I am using 5/16″ HT chain with a 3/8″ G209A shackle with a Spade S140. I think the 5/16″ HT chain links do take the body of the shackle, so I can use a single shackle.
I was wondering if you were using two shackels for some other reason, but it sounds like that was the only way to connect the chain to the anchor.
Thanks!