Which way round should the shackle be?

[IslandHopper]

Originally Posted by Dockhead

Chains with enlarged end links can! I had my anchor chain made that way, and it's fairly common practice here.

That doesn't help me, however, as my bow roller is the limiting factor.

I started using the same as you some years ago when running my own 16m fishing boat, the ears on the shackle always snagged on the rim of the hawse pipe, when i renewed the chain I got the enlarged link and flush pin shackle, problem solved....

I still use the same set up today on my sail boat, although I did use two flush shackles until it came time to replace the chain.....

[noelex 77]

Originally Posted by Dockhead

Now someone on here cuts the ears off of a Crosby shackle and welds the pin in place.

I would be reluctant to weld the pin. The heat treating involved in making the shackle G8 could be compromised.
I am no welding expert. I suspect it would be possible to weld the pin without significantly reducing the strength, but with a small component like a shackle that heats up easily it would be difficult and better avoided.

The shackle pin could be secured by peening and/or the use of some of the heavy duty Loctite 271. (I would do both)

The pin head could then be cut off.

Your original plan of using HR shackle with Loctite (probably medium strength) 242. is a very common and successful practice (many swivel pins are also secured this way), but makes me a little nervous. There is only one shackle pin holding the boat and I am a belt and suspenders type of guy.

The HR shackle I think is perfectly safe, but the above approach gives you a connection with greater strength (reassuring give the risk of side loading), removes the use of disimilar metals underwater. It also removes the controversial problem of using stainless steel especially 630 SS in this situation. (The HR shackles are made from 630 stainless steel which is less suitable for prolonged immersion than the more common 316L ). Finally it would be cheaper.

[bobsadler]

We're operating in 1500m and all our supply vessels and anchor handlers are DP1 or 2 as well

[Andrew Troup]

If I was forced to weld a heat treated high-grade shackle, which was galvanised, I would proceed very carefully indeed.

Noelex was exactly right (again ! )

It's both possible, AND difficult.

Given that you're cutting the other end off, I guess you're taking some measures (including regular inspection) to avoid corrosion of the bare alloy steel.

So you could power wire brush around the end thread of the pin, to clear away as much zinc as possible, then grind or (preferably) machine a chamfer on the end of the pin, deep enough to clear any zinc away from the weld.

Similarly, countersink the threaded hole in the shackle body to a suitable chamfer to provide a symmetrical V when assembled.

Using a TIG welder with a small electrode and a suitable filler rod for 800 MPa alloy steel*, make three SMALL welds, just tacks, spaced at 120 degrees, in the middle of the V.

Allow to cool between each tack.

This way, the metallurgy of the welds (hopefully! if you cleared the zinc far enough away ....) will not be subject to cracking, and the heat treatment of the shackle, to which it owes its very high stress rating, will not be destroyed.

Forget about doing autogenous welds (ie with no filler rod) - they will crack in this high-alloy steel. Forget about stick welding: you will destroy the strength of the entire shackle. And gas welding or brazing are completely off the menu.

TIG is the only welding method with a sufficiently small, intense weld pool.

* On further reflection: use a 309 (Stainless) filler rod, which is constituted for welding high alloy and dissimilar grades of steel, and has a remarkably degree of metallurgical compatibility. Or RSP would be OK, too.

Neither of these will corrode to anywhere near the same degree as high alloy, non stainless steel. And there will not be enough area to create galvanic corrosion issues for the zinc.

And they may even tolerate a bit of zinc melting into the pool - I would not swear to this, because it's a "passed down" piece of conventional practical welder's lore, rather than based on deep metallurgical insight. They're certainly not fussy the way a high tensile filler rod is.

Whoever does the TIGging, if they know what they're about, will be able to see if the weld is OK as they're making it. But make sure they make each weld SMALL ! Just a circular spot, to fill the chamfers.

- - - - -

I would not personally trust to Loctite alone, in this particular application. The unscrewing forces on a shackle, by a combination of the nutating action of the heavily loaded chain and the cyclical tugging of a chain at a slight angle, can be prodigious.

We once had to let a friend raft up to us who had lost his anchor on a filthy night, and I know for a fact that same shackle pin had been profoundly immovable just a week earlier when he went to change it for a new one, the way galv shackles get after 10 years or more of regular long term immersion - it looked as though the pin had become one with the shackle, and as if the galv had coupled across the interface, and in places the little barnacles had sealed the deal.

Peening, as suggested by Noelex, (and in conjunction with "High Strength Retaining Compound" Loctite) is probably the best plan, bit it would probably pay to drill a dimple or a deep countersink in that end of the pin, and then put a bearing ball or round-ended punch in the dimple and whack it relatively seldom with a VERY heavy club hammer, to efficiently splay the end of the pin, without having to wale into it the way a Grade 80 pin would otherwise require, which might damage the shackle.

Il faut bien souffrir pour être bien costaud, et puis léger comme diable, en même temps.

[Dockhead]

Originally Posted by Andrew Troup

If I was forced to weld a heat treated high-grade shackle, which was galvanised, I would proceed very carefully indeed.

Noelex was exactly right (again ! )

It's both possible, AND difficult.

Given that you're cutting the other end off, I guess you're taking some measures (including regular inspection) to avoid corrosion of the bare alloy steel.

So you could power wire brush around the end thread of the pin, to clear away as much zinc as possible, then grind or (preferably) machine a chamfer on the end of the pin, deep enough to clear any zinc away from the weld.

Similarly, countersink the threaded hole in the shackle body to a suitable chamfer to provide a symmetrical V when assembled.

Using a TIG welder with a small electrode and a suitable filler rod for 800 MPa alloy steel*, make three SMALL welds, just tacks, spaced at 120 degrees, in the middle of the V.

Allow to cool between each tack.

This way, the metallurgy of the welds (hopefully! if you cleared the zinc far enough away ....) will not be subject to cracking, and the heat treatment of the shackle, to which it owes its very high stress rating, will not be destroyed.

Forget about doing autogenous welds (ie with no filler rod) - they will crack in this high-alloy steel. Forget about stick welding: you will destroy the strength of the entire shackle. And gas welding or brazing are completely off the menu.

TIG is the only welding method with a sufficiently small, intense weld pool.

* On further reflection: use a 309 (Stainless) filler rod, which is constituted for welding high alloy and dissimilar grades of steel, and has a remarkably degree of metallurgical compatibility. Or RSP would be OK, too.

Neither of these will corrode to anywhere near the same degree as high alloy, non stainless steel. And there will not be enough area to create galvanic corrosion issues for the zinc.

And they may even tolerate a bit of zinc melting into the pool - I would not swear to this, because it's a "passed down" piece of conventional practical welder's lore, rather than based on deep metallurgical insight. They're certainly not fussy the way a high tensile filler rod is.

Whoever does the TIGging, if they know what they're about, will be able to see if the weld is OK as they're making it. But make sure they make each weld SMALL ! Just a circular spot, to fill the chamfers.

- - - - -

I would not personally trust to Loctite alone, in this particular application. The unscrewing forces on a shackle, by a combination of the nutating action of the heavily loaded chain and the cyclical tugging of a chain at a slight angle, can be prodigious.

We once had to let a friend raft up to us who had lost his anchor on a filthy night, and I know for a fact that same shackle pin had been profoundly immovable just a week earlier when he went to change it for a new one, the way galv shackles get after 10 years or more of regular long term immersion - it looked as though the pin had become one with the shackle, and as if the galv had coupled across the interface, and in places the little barnacles had sealed the deal.

Peening, as suggested by Noelex, (and in conjunction with "High Strength Retaining Compound" Loctite) is probably the best plan, bit it would probably pay to drill a dimple or a deep countersink in that end of the pin, and then put a bearing ball or round-ended punch in the dimple and whack it relatively seldom with a VERY heavy club hammer, to efficiently splay the end of the pin, without having to wale into it the way a Grade 80 pin would otherwise require, which might damage the shackle.

Il faut bien souffrir pour être bien costaud, et puis léger comme diable, en même temps.

It wasn't me that used this technique, so I don't know for sure, but I think they were small tack welds just intended to immobilize the pin, not weld it together with the body of the shackle.

As far as regular inspections are concerned -- it seems to me that it's best just to replace shackles regularly. That's what I do with mine. At least once a year I re-Loctite the pin; every other year I just replace it, and retire the old one to utility duty in my box of old blocks, sheaves, shackles, and other rigging stuff.

Seems to me that there still isn't a really ideal solution out there. Someone should make a high grade galv shackle, it seems to me, with no "ears" on the pin, and with some really bomb-proof mechanism for locking the pin. I am also not entirely comfotable with Loctite as the sole locking mechanism, although it seems to be ok and is used by people respected by me (Vyv Cox was a long-term liveaboard in the Aegean besides being a good engineer). I have never heard of a Loctited shackle coming undone, although there are many stories about shackles secured in other ways coming undone.

[twoblocktom]

I was a tube welder for 20 years. And am now a CWI currently inspecting welds for a large construction company. And I have an opinion too! The heat of welding will effect the hardening of a shackle and the zink used to galvanize will contaminate a weld. Also when welding it is customary to use the same alloy filler as the base metal being welded. However growing up on a farm taught me to make due with what I had. So, Zink can be removed by grinding, 309 SS filler can be used to join carbon steel, if the weld were small enough the amount of strength lost may not enough to cause a problem, and two shackles should be joined "bell to bell". But I also know that if you screw up one thread enough you will never get that shackle apart, not in this lifetime! That could be done by welding without a much of a heat effected zone, but also a good center punch and a 4lb. Hammer to the last thread showing. If I were hanging off one 300' in the air I would beat hell out of it, that would do it!

[Pelagic]

I am curious..... Has anyone ever experienced a well tightened galvanized anchor shackle pin coming easily undone?

[boatman61]

For all you techies talking Loctite and welding... try something that's been done since shackles were invented.. tighten the pin till its sticking well outa the other side then peen it with a ball pin hammer.. that's means beat the crap outa it till it mushrooms..
6 pages and 82 posts.. sheesh..

[Andrew Troup]

Originally Posted by Pelagic

I am curious..... Has anyone ever experienced a well tightened galvanized anchor shackle pin coming easily undone?

http://www.cruisersforum.com/forums/...ml#post1530110

near the bottom ..

[sparrowhawk1]

Originally Posted by boatman61

For all you techies talking Loctite and welding... try something that's been done since shackles were invented.. tighten the pin till its sticking well outa the other side then peen it with a ball pin hammer.. that's means beat the crap outa it till it mushrooms..
6 pages and 82 posts.. sheesh..

Boatman you're obviously an experienced skipper. But I've never had a shackle were the threads extend past the body. And zip ties have served me well. Edit. I understand the talk about cutting off the ear and welding is for it to go over the bow roller

[boatman61]

Originally Posted by sparrowhawk1

Boatman you're obviously an experience skipper. But I've never had a shackle were the threads extend past the body. And zip ties have served me well.

Use more muscle.. not just finger tight plus one n a half turns.. a marlin spike and adjustable will get you there..

[Jim Cate]

Ya know, if I was all that worried about the pin coming unscrewed, and about any welding technique stuffing the heat treatment, and the pin did not extend far enough to allow good peening, I would do the following:

At the meeting edge between pin and shackle body, drill a small (~1 mm) hole axially into the shackle after tightening to max torque. Make it perhaps 3-4 mm deep. drive a bit of round stock that is an interference fit into the hole (like a bit of welding rod) and saw it off flush. Done. No chance of pin unscrewing, no significant weakening of the shackle assembly. Essentially no cost.

What's not to like?

Jim

[model 10]

Originally Posted by Jim Cate

Ya know, if I was all that worried about the pin coming unscrewed, and about any welding technique stuffing the heat treatment, and the pin did not extend far enough to allow good peening, I would do the following:

At the meeting edge between pin and shackle body, drill a small (~1 mm) hole axially into the shackle after tightening to max torque. Make it perhaps 3-4 mm deep. drive a bit of round stock that is an interference fit into the hole (like a bit of welding rod) and saw it off flush. Done. No chance of pin unscrewing, no significant weakening of the shackle assembly. Essentially no cost.

What's not to like?

Jim

You could do that the more normal way which is drill a hole all the way through the boss it and put a pin through that you could tap out again someday.
A really old way of doing this is; the shackle pin sticks out far enough for a wood cotter pin through the metal shackle pin. You can always get the pin out in a hurry.

[Wotname]

Originally Posted by boatman61

For all you techies talking Loctite and welding... try something that's been done since shackles were invented.. tighten the pin till its sticking well outa the other side then peen it with a ball pin hammer.. that's means beat the crap outa it till it mushrooms..
6 pages and 82 posts.. sheesh..

Well I do like simplicity, but this still sounds like hard work; I (perhaps) might just knock a like of the galv. off and let the rust do it's work as the poor man's Loctite.

Originally Posted by Jim Cate

Ya know, if I was all that worried about the pin coming unscrewed, and about any welding technique stuffing the heat treatment, and the pin did not extend far enough to allow good peening, I would do the following:

At the meeting edge between pin and shackle body, drill a small (~1 mm) hole axially into the shackle after tightening to max torque. Make it perhaps 3-4 mm deep. drive a bit of round stock that is an interference fit into the hole (like a bit of welding rod) and saw it off flush. Done. No chance of pin unscrewing, no significant weakening of the shackle assembly. Essentially no cost.

What's not to like?

Jim

Nice idea Jim but still a lot of work . Oh, I forgot cruisers have more time than us non-cruisers .

Dockhead could rework this concept slightly for his dilemma concerning the protruding ear of the pin. Cut the ear off and radially drill though end of the shackle (and pin), and insert suitable pin. This would also secure the pin from turning.


Me, I just mouse in the usual way and hope for the best! Sometimes I use soft galv. tie wire and sometimes I use SS lockwire. I'm sure both are unsuitable in one way or another but I haven't been game to date to ask for a CF opinion on the matter.

[JonJo]

Originally Posted by Wotname

Well I do

Me, I just mouse in the usual way and hope for the best! Sometimes I use soft galv. tie wire and sometimes I use SS lockwire. I'm sure both are unsuitable in one way or another but I haven't been game to date to ask for a CF opinion on the matter.

I cannot think why you feel reticent, I'm sure now that you have made mention you will enjoy some good advise.

One key in all of this is simply to monitor your attempts at security each time prior to deploying your anchor - even the best mousing (which seems to be the preferred option) can degrade. If you sit at anchor for weeks at a time your solutions will not necessarily be the same as someone who anchors a few times a year.

Jonathan