Shackle bolt in shank or chain?

[psneeld]

How does the hive feel about swivels?

I have always felt they are a weak link, add moving parts not easily inspected and can be of questionable origin and not really necessary.

Comments

The old cheapo galvanized are easy to inspect and the one I use is rated higher than the chain I believe. So not really a weak link any more than shackles.

You could easily upsize one by using a shackle on the chain. The larger ones probably swivel even easier.

 

[Tom.B]

I'd like you to tell us what the "chain motor" is and what is meant by "find its center"? If you put the pin through the last chain link the shackle will almost always be not lined up .. the chain link will go to one side of the gap between the shackle arms .. not on center. It would seem one shackle arm will be loaded more than the other.

Fair enough. I am not enough of an expert to say one way or the other. My question is: Wouldn't that be true both directions?

 

[SCOTTEDAVIS]

The old cheapo galvanized are easy to inspect and the one I use is rated higher than the chain I believe. So not really a weak link any more than shackles.

You could easily upsize one by using a shackle on the chain. The larger ones probably swivel even easier.

Interesting, I know the one you are talking about and you are right it is easier to see the link then the high dollar stainless ones.

I was told (perhaps wrongly) that chain is rated at about 1/3 of it's breaking strength (working load V breaking) but the connections and swivels are rated at closer to actual breaking strength.

I don't use one but can see it helping for when the anchor snubs up to the pulpit and needs to flip over to do so. Is that the reason to have one or is there some advantage when engaged to the bottom?

May look at an over-sized galvanized one.

 

[Nomad Willy]

Tom.B,
Yes both ways.
But the deciseive element of which way is correct hasn't been mentioned yet that I can recall. It's what your'e presented with. If you have an anchor w a round hole in the shank ..... or if you're rigging a spreader bar w round holes in it .... Or if the ends of the shackle won't fit through the last link of a chain ... . First thing first .. what will fit where. Some anchors have slots too narrow because the anchor is under under sized and some skippers have under sized chain and a big anchor cuse someone on TF said size matters.

It's interesting to explore things that are usually not considered.
So yes the gap between the shackle ends is usually much bigger that the pin or shackle head so the chain, bolt or pin used there will hold to one side and turn the shackle off the CL of the shank and rode. Either way isn't perfect.

I see some now using plastic tie wraps instead of metal wire.
What think of that?

 

[sunchaser]

I see some now using plastic tie wraps instead of metal wire. What think of that?

IMHO a bad idea. SS seizing wire is much preferred. I use multi colored plastic ties to mark anchor feet. They wear out frequently just due to being dragged around on the seabed.

 

[sunchaser]

I was told (perhaps wrongly) that chain is rated at about 1/3 of it's breaking strength (working load V breaking) but the connections and swivels are rated at closer to actual breaking strength.

When buying chain or alloy shackles on line from Crosby or 1st Chain Supply they show WLL and breaking limit/strength. Rigging supply house catalogs do the same. This lifting stuff we (should) use is based on science, not an art. I've been involved with non-destructive testing for shovel and mine hoist rope and attachments. Fun stuff and vitally necessary in the real world.

 

[Peter B]

The old cheapo galvanized are easy to inspect and the one I use is rated higher than the chain I believe. So not really a weak link any more than shackles. You could easily upsize one by using a shackle on the chain. The larger ones probably swivel even easier.

Hey Psn, you never answered the question...

Originally Posted by psneeld
Have thought about it and went out and played around with anchor chain and shackle. On my set up, and others I have used...but not all..... I do think one way is a little better.

My question was...
And that way was...?
__________________
Pete

 

[psneeld]

Pin in chain...


Manyboats answered it saying which "camp" I was in and I thought it clear back in post #3...


Post #3 "depending, I too would say pin through chain and round part in anchor...there should be no way for the anchor tackle to change 90 degrees and exert an uneven force on the shackle...it should all rotate with pull on the chain. "


However, it is more about how the shackle will function. If the anchor only has a tiny hole for a shackle pin...then there's you answer...but most anchors have a slot that allows a large shackle to be rigged either way.


If so then it is best to use a shackle that the pin end is just barely wider than the chain allowing little rotation and the round part goes in the anchor.


After reading 3 0r 4 safety articles and watching several videos on safe shackle use, it is pretty clear the best way to use them.

 

[Nomad Willy]

"Clear the best way to use them"

Not at all clear as there are many anchors that have a round hole on the anchor shank. That was the reason for the thread .... because it wasn't clear. Is it clear because that's what you see? Show me a large ship anchor w a slot in the end of the shank for the rode.

 

[ranger58sb]

How does the hive feel about swivels?

I have always felt they are a weak link, add moving parts not easily inspected and can be of questionable origin and not really necessary.

Don't think I've seen consensus, but I do think there have been a couple (or more) semi-recent swivel threads either here and/or on Cruisers Forum.

My first take-away has been: there are swivels, and then there are swivels. Some brands/models good (or at least acceptable), some not so much... and you (probably) get what you pay for. (Single-directional vs. multi-directional articulation, jaw design, clamping mechanisms, metal alloy, etc., all in play.)

Second is about actual implementation. Attachment method to anchor shank and to chain important, especially to reduce/mitigate side-loading.

Third is that I'd likely not use one if our anchor would always present itself properly to the roller upon retrieval... but that'd mostly just be about avoiding the expense, not an indictment of swivels per se.

As with most things boat, I can't bring myself to consider any one/single ground tackle component without seeing all of them (rode, anchor, shackles and so forth) -- plus environmental factors like holding ground, setting technique, weather, etc -- in system together.

-Chris

 

[sunchaser]

I'd likely not use one if our anchor would always present itself properly to the roller upon retrieval... -Chris

When we got rid of our swivel I was leery of "presentation" to the bow roller. At times it is necessary (and easy) to rotate the anchor with a boat hook and then all was well. But, there were times I had to do the same even with the high end swivel!

Our anchor area and working over the side is easy, some vessel not so and this is where a swivel becomes important. But at several hundred bucks a pop for the larger ones it is another "can I do without it" decision. The breaking strength limits on the cheaper ones are scary

 

[Nomad Willy]

On a swivel thread some time ago the "hive" decided the swivel was (to varying degrees) not necessary and a weak link.
It should be w all chain that the anchor would come up exactly the way it went down if the roller had a groove. But passing the chain/line junction on a combination rode it could come up any which way.
A boat on our float has a swivel attached to the shank such that heavy side loads would be certain. Looks like a high end barrel shaped thing.
I hand pull the last of the rode so could care less about swivels. Frequently I'm glad I own a smaller boat.

 

[psneeld]

Well...clear to me which way and all the "ship anchoring" studies I have read clearly show how ship anchoring due to their proportionately smaller tackle is a different animal and not comparable to pleasure boating for numerous reasons..so I really don't care how they rig their anchors.

As far as swivels rigged improperly...well...like shackles ya just gotta figure them out.

 

[Nomad Willy]

I have.

 

[woodscrew]

Pin through the chain, bow through the shank so the bow is free to swivel side to side with changing angles of pull. The other way has the pin locking up in the shank when the angle of pull gets far enough away from in line.

 

[Nomad Willy]

woodscrew wrote;
"so the bow is free to swivel side to side with changing angles of pull."

You present this as if that was an advantage.

Many anchor manufacturers provide a round hole obviously intended for a shackle pin. No shackle end would fit through the hole. They see no advantage to allowing the shackle to rotate or "swivel" as you say. Most shackles called anchor shackles have a larger "bow" as you say w a much larger main shackle ID. The last chain link may be attached to the "bow" (if the pin end of the shackle will fit through the chain link) or a smaller additional shackle is employed. In either event the 2nd shackle or the last chain link will move around the shackle "bow".

In the pic is an example of an extremely large dia anchor shackle on an old flying boat anchor. The shackle bolt of the anchor shackle is permenantly attached to the anchor therefor the intent was obviously that the chain (or line) be attached by the additional shackle. The photo of the anchor is as I bought it.

Most anchor manufacturers now offer their anchor shanks w a slot so the shackle can be attached either way. Over many many decades anchor manufacturers have offered both attachment options so it's impossible to say that one is right. If you put the pin to the chain the chain link will slide to one side loading the shackle unevenly causing a slight weakness. If you put the pin through the hole in the end of the shank the sideways pull on the shackle will be a slight weakness. Either way is not structurally not ideal. But only not ideal when the anchor and rode are not aligned. And the only time when there is high loads on the rode to shank attachment is when the rode and shank are aligned. However w the pin through the chain the shackle will be slightly mis-aligned and the chain link will be over to one side not only when the rode and anchor are mis-aligned but when they are lined up. So the slight disadvantage will always be present unless washers or bushings were employed to center the chain link on the pin.

Looks to me like there's very slight advantage to pin in the shank .. especially if the pin and shank hole were a snug fit. I consider the pin in the shank as shown in post #1 whereas the shackle is of high quality high strength manufacture and of a U shape w no "bow" at all to be the best arrangement. Another advantage to this this arrangement is that the shackle is small w a minimal width so the shank's bottom penetration is not unnecessarily impeded by the anchor shackle.

 

[psneeld]

If people read technical writings on the use of shacles, the recurring theme is using a bow shackle to spread a load and more importantly, maintaining the line of pull so the pin swivels the least.

In some cases that would be pin in chain, some pin in anchor. If a particular way is desired but play is possible, bushing the pin is recommended.

Understanding why things are done is important if you see conflicting ways with no apparent reason.

 

[Nomad Willy]

The anchor and anchor rode insure that probably well over 99% of the time the anchor and rode are in perfect alignment.

When given a choice I'm quite sure it dosn't matter which way the pin goes. But if somebody would like to make case for one I'll be interested.

psneeld I do like your idea (if it's your idea) about bushing the pin in the shank. But a bushing will require a considerably larger hole to be drilled in the anchor shank thus weakening it so I'll pass. Drilling slightly over and just using a slightly larger pin would'nt wear over 50 years as well but almost certainly be stronger.

 

[psneeld]

That's the whole point...a bushing isn't my idea or a WAG...like so many posts here.


Plus it is not a bushing for wear on the pin...it is to ensure there is only straight pull on the pin. Try looking it up.


Having read numerous articles, PDFs from riggers manuals, OSHA safety bulletins, etc...it is pretty clear what to do...if anyone just want to wag it fine...but then all the arguments of anchor holding power and chain/anchor selection, weak links such as swivels and connector links are all hilarious.

 

[woodscrew]

So, I never thought about this until I read an article somewhere a couple of years ago. It doesn't make much difference either way. Unless your anchor is stuck somehow ( in a rock/coral crevice, buried way deep in hard bottom) and will not pivot around with a wind shift or tide change. With the shackle pinned to the anchor the chain will be side loading the shackle and potentially bending it. Whereas if the shackle is pinned to the chain the bow part of the shackle can slide around in the shank, no unfair loading on the shackle. Then you only have to worry about bending your anchor.

 

[psneeld]

So, I never thought about this until I read an article somewhere a couple of years ago. It doesn't make much difference either way. Unless your anchor is stuck somehow ( in a rock/coral crevice, buried way deep in hard bottom) and will not pivot around with a wind shift or tide change. With the shackle pinned to the anchor the chain will be side loading the shackle and potentially bending it. Whereas if the shackle is pinned to the chain the bow part of the shackle can slide around in the shank, no unfair loading on the shackle. Then you only have to worry about bending your anchor.

If the shackle is held pretty straight in either the anchor or the chain link...according to rigging best practices that I have read it shouldn't matter.

However a long pin in either chain link or anchor shank and the shackle can twist and be compromised..pick your poison.

Without adding anything...whichever way the shackle can twist the least is the best way.