Chain and Shackles, WLL

I just received my HamiltonMarine.com catalog and I am reminded of a very important topic: anchor chain and shackles WLL, working load limits!

Many of us use Hot Galvanized Grade 40 Chain, HT, 5/16" which has a WLL of 3900 lbs. Then we go and use a regular 3/8" shackle which has a WLL of 2000 lbs. Mix in an anchor chain swivel or eye swivel and we could have a real weak link in our anchor chain connection.

According to Hamilton Marine, you should always go up one size from the chain to the shackle. For example: 5/16" chain uses a 3/8" shackle (5/16" chain, 6/16" shackle, one size up)

In this example, the 5/16" grade 40 chain will have a WLL of 3900 lbs. This 3/8" Crosby High Test Screw Pin Shackle will have a WLL of 4410 lbs. So, we now have a shackle that is stronger than the chain! Exactly what we want.

If you need larger chain, then the next size up would be: 3/8" Grade 40 Chain with a WLL of 5400 lbs. Then the shackle would be 7/16" Crosby HT screw pin shackle with a WLL of 5880 lbs. Again, this shackle is stronger than the chain.

My question to you is.....do you know the WLL of your anchor chain shackle? Do you know if you have a Crosby High Test Screw Pin Shackle?

You should look for USA made shackles from "the CROSBY group inc" which are available from HamiltonMarine.com in Maine.

Yes, you are right, I was only using that as an example. The key is to use an HT shackle. Thanks for the link, I added the pictures here as well...

I am replacing my shackles with new ones, due to age, no other reason. Here is the direct link to the HT CROSBY SHACKLES and their information. This is what I am using on my G4 HT 5/16" Chain.

SHACKLE ANCHOR 3/8" USA 2TON HI TEST SLVR PIN 105393
ANCHORING / SHACKLES, SWIVELS & LINKS / SHACKLES

3/8" HT Shackle:
store.hamiltonmarine.com/browse.cfm/shac...105393-/4,18243.html

All Shackles:
store.hamiltonmarine.com/browse.cfm/shackles/2,1034.html

Here is one more resource for these Crosby HT Shackles:

www.riggingwarehouse.com/products/RIGHAR...D01@@2e22@@2e04.aspx

G-209A Crosby® Alloy Screw Pin Anchor Shackles are forged alloy steel-quenched and tempered, with alloy pins. These shackles meet the performance requirements of Federal Specification RR-C-271D, Type IVA, Grade B, Class 2, except for those provisions required of the contractor.

www.riggingwarehouse.com/

PDF file on CROSBY Shackles




Hayden

Here are some photos of these CROSBY SHACKLES. These are the 3/8" shackles for use with 5/16" chain. WLL working load of 2T, two tons, 4,000 lbs.

I bought these from:
www.riggingwarehouse.com/products/RIGHAR...D01@@2e22@@2e04.aspx

I would avoid the use of any swivel. The center pins cannot be inspected.
I do not have one.
Hayden

Clarence
We kept our 5/16" chain with our 55lb Rocna. It is working well.
Hayden on anchor Marsh Harbor Abaco