Anchor Shackle

[Acadia]

Hello,

I've been searching posts trying to figure out what kind of shackle I should put between my anchor and chain.

Although this might seem like an easy answer for most, there is one thing that makes me scratch my head a little.

So if the anchoring system is only as strong as it's weakest link, I'm having a hard time finding a shackle that will match the specifications of the chain.

The chain is 5/16 HT, the anchor is a Mason supreme 45lbs and the boat is 18,000lbs

I've been looking at the Crosby shackles rated at 3/4t. Now I figure that it's probably more than enough but the working load of the chain is more than double that (if I'm not mistaken) so is there an alternative?

Also, I've see a few opinions out there about using SS shackles. Should I stay away from them?

Is there a specific difference with an anchor shackle VS a regular shackle?

Thanks

[btrayfors]

Good question.

There are basically two ways to go:

(1) have oversize links welded onto your 5/16" HT chain to accommodate larger shackles; or

(2) use alloy shackles which are much stronger than the usual shackles you see at West Marine or most other chandleries.

I chose the latter, and purchased a bunch of alloy shackles made by Columbus McKinnon (CM) for myself and my friends. I also have 5/16" HT chain.

You can get the shackles in several places, but here's a good place to start and to learn about them and about chain:

Shackles, Alloy Steel

Bill

[Sandero]

They say not to use stainless steel with galvanzied. You'll get corrosion. But if you are monitoring your chain/anchor connection you might consider using a non prescribed, but stronger metal and watching it carefully and change it "regularly". The connection of chain to anchor is quite visible as it's right up on the foredeck.

I certainly wouldn't mismatch metals in a mooring which is submerged for months on end.

[Cheechako]

I had 5/16 HT chain and 3/* shackles would fit the cahin. I s that what you are using? I would avoid welded stainless. Sail mag (of all places ) has had some good info this year. The latest copy shows pictures of stainless chain which failed in a hurricane in the weld/heat effected zone on each link. One of the problems with welding stainless is that the grain structure is changed by the heat. Unless the welded product is solution heat treated after welding (and this will take all the cold-work strength out of the base material) the heat effected zone right next to the weld or the weld itself is prone to cracking or corrosion.

[Kanani]

I used 3/8" high tensile shackles on my 5/16" HT chain. I used a 1/2" swivel.

More important than the shackle/swivel that you use is the seizing of the shackle pin. I used 4 wraps of molly seizing wire, twisted it for about 1/2", tuck it into the wraps and checked it often.

I have seen more boats go aground from a lack of shackle seizing than any other reason. Often in calm weather, after a blow. In all my years of cruising, I never saw a failed shackle, either on my boat or anyone else's boat. I sat at anchor in over 100kts of wind on Stewart Island NZ for 3 days. No issues.

I did see a chain snap on a neighbor yacht while anchored in boulders off of Raoul Island in the Kermedek Islands, north of NZ. We were all on shore when it happened and thankfully, the boat just drifted out to sea and we were able to take the skipper out to retrieve it. Boy was he shocked when we headed back to the boats and his yacht was about a mile off-shore .

S/S is not a good medium for ground tackle IMO. It is a soft material and bends easily. I know that they make S/S alloys that are stronger than 302 or 316 S/S but I would not use it myself.

[Acadia]

Thanks for the great replies, I think I will go with alloy steel.

I tried getting a bigger shackle than 5/16th on there but with no luck.

Happy Holidays

[Jmolan]

We stopped using shackles over ten years ago in the trawling industry in Alaska.

We use what we call a "hammerlock" It runs about 3 times the strength of a shackle for the same size.
I have had a heck of a time this morning trying to find some examples on line. Here are the two I came up with.

Läs publikation

http://www.highlandrigging.com/15.html

If you are on either coast check with a comerical fishing outfit.

The Gunnebo is what we use. The highlandrigging does not give a very good presentation. Crosby and Campbell chain also make hammerlocks. On Gunnebo they call them "Coupling Link G'

It always baffled me how you had all this high strength chain and anchor and then use a shacle that is so much lower in working load.

[Cheechako]

If the fishermen use it in AK then take heed! Has anyone tried using Quicklinks? I used them on a couple of my boats, bought the high quality 316 ss ones (Wichard?). As I remember they are rated far above the chain strength. They go through the roller easy. I just seized back and forth around the nut with monel wire. I always monitored how the link looked when pulling the anchor as it was a bit of an experiment for me. I saw not problems. Held in 70+mph (short duration) winds. I dont think they are made with any welding... but not sure.

[Kanani]

Originally Posted by Acadia

Thanks for the great replies, I think I will go with alloy steel.

I tried getting a bigger shackle than 5/16th on there but with no luck.

Happy Holidays

I am confused about what size/type chain that you have .

A 3/8" shackle bolt should go through a 5/16" HT chain link with no problem.

If the shackle bolt won't go through the last link in the chain, try cutting that link off and using the next link. Maybe the last link is distorted.

[perchance]

If it's good enough for the guys who make their living from the sea it's good enough for me.

[btrayfors]

The CM alloy shackles have pin sizes larger than the shackle size. For example, the 5/16" shackle has a pin diameter of 3/8" (which does fit nicely in 5/16" HT chain), and the 3/8" shackle has a pin diameter of 7/16".

I forget which is the largest size to fit my 5/16" HT chain (with a nominal inside diameter of .49"), but I'm on my way to the boat right now and will measure it.

Bill

[GordMay]

Originally Posted by Cheechako

If the fishermen use it in AK then take heed! Has anyone tried using Quicklinks? I used them on a couple of my boats, bought the high quality 316 ss ones (Wichard?). As I remember they are rated far above the chain strength...

I don't think I've ever seen a (threaded) "Quick-Link" rated anywhere near the same as an equivalent diameter chain.
The Quick Link wire diameter is smaller than it's threaded diameter, so requires a larger chain opening.

[btrayfors]

OK, here's some real world data.

First, my anchor chain is 3/8" HT, not 5/16" HT.

This chain is rated at 2.7 tons WLL. Each link measures .60" inside, slightly over 1/2". So, it will easily take a 1/2" pin, which is what the 7/16" CM Steel Alloy shackles have and which is what I have fitted to the chain and anchor.

These 7/16" shackles have a measured pin size of .48", and are rated for 2.6 tons working load. Their breaking strength is FIVE times that, or 13 tons....26,000 lbs. I could almost pick up my 27K lbs displacement boat with a single shackle :-)

I also have several 3/8" CM red-pin steel alloy shackles aboard. These have pins measuring .423" (nominally 7/16") and are rated at 2 tons WL or 10 tons breaking strength. They will easily fit into 5/16"HT chain which, BTW, is also rated at 2 tons WLL.

Got a couple of 1/2" CM red-pin monsters, too, for a rainy day. They have a pin size of .85 (less than 5/8") and are rated at 3.3 tons WLL or 16.5 tons breaking strength. Probably good enough for the towline on my 9' Caribe inflatable :-)

Merry Christmas, all!!

Bill

[rebel heart]

Just in case anyone finds this thread:

I have a 60lb Manson Supreme and 5/16th HT chain. This shackle goes through the anchor and sits inside a standard (not oversized) link. It's high quality and looks great:

Anchor Shackle - High Test - Galvanized - 3/8"* - *Shackles - High Test* - *Anchoring Hardware* - *Anchoring & Docking* - *Main Deck

[Livia]

Originally Posted by rebel heart

Just in case anyone finds this thread:

I have a 60lb Manson Supreme and 5/16th HT chain. This shackle goes through the anchor and sits inside a standard (not oversized) link.

Super helpful RH and I did find this in a later search - Downwind changed their site around so I am including an updated link here. 3/8" is the size RH originally linked to:

Anchor Shackles - Galvanized High Test - Shackles - High Test - Anchoring Hardware - Anchoring & Docking - Downwind Marine