What kind of chain do I have?

[TacomaSailor]

I decided to replace the shackle on the 5/16" BBB chain and the swivel that I have never wanted in the system. The chain was put on the boat when I purchased the boat new in 1995. I specified Campbell 5/16" BBB and it was a reputable high end sailboat brokerage that outfitted our new Caliber 40.

Today, I tried to put in a new Crosby 7/16" G209A shackle that has a 1/2" pin. The pin can be driven thru the BBB chain but the weld on the inside of the chain link prevents the link from rotating on the pin. The weld causes the pin to bind and prevents smooth movement of the shackle. When a load is put on the chain - the 2nd link puts sideways on the weld of the first link - not good!

That Crosby shackle works fine on the 5/16" GT HT chain that I use on my other anchor. That chain also is specified to have a 1/2" inside link width but the the weld is smaller and smoother.

I went back thru my maintenance log and noted that in 2000 I had the same problem with a 1/2" pin and that is why I put the swivel in the system because it's pin was slightly smaller and fit thru the 5/16" BBB chain link.

All the other chain specs for width and length match what I would expect for a 5/16" BBB chain.

So what kind of chain do I have ?

Is there a way to get the 1/2" shackle pin to rotate freely?

[Panope]

With my BBB chain, I can only fit a shackle that is "one size larger" than the chain. For me that's 3/8" chain and a 7/16" shackle.

This matches your experience of not being able to fit a shackle that is "two sizes larger" than the chain.

BBB is not as strong as HT so no worry about strength - especially if using the stronger Crosby shackle. Just use a 3/8" shackle and it will be plenty strong.

Steve

[pbiJim]

I would just use a 3/8" shackle. If you are worried about strength, then go one grade higher than you had planned.

http://www.yarcable.com/crosby/docs/...kle%20Info.pdf
https://www.certex.com/wp-content/uploads/hardware.pdf

[colemj]

Use a second shackle between the chain shackle and the anchor?

Galvanizing could account for a small difference? The chain could be 8mm and not 5/16"? The chain you have was built to a different reference standard than the other? The old shackle was metric and the new imperial?

13 years on chain is way, way better than we get.

Mark

[perchance]

File the weld down since it adds nothing to the strength of the chain anyway but you will wind up with a rust spot where the zinc is removed.

[TacomaSailor]

"13 years on chain is way, way better than we get."

Well - the 5/16" BBB and 44# Bruce is our secondary anchor and has only been deployed about 10 times in the last 12 years - since we bought the Spade 66.

The BBB lives on the bow and in a well drained anchor locker. It all gets washed with fresh water every month and looks like new.

[evm1024]

Try a few different links and a different shackle (stay with the 209-a) some combination will fit better and losing a few links is not a problem.