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Old 18-11-2010, 16:41   #1
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How to Thread-Lock Anchor Swivel ?

Hi anchoring experts

I have a snazzy new SS Anchor Swivel which has two Allen head bolts which are flush when fully in place. similar to this Anchor Swivel

This is going to replace a unidirectional glavanized swivel which is moused with monel wire.

What (if anything) do other members use to stop the bolts coming adrift ?

Should I use locktite ? Any particular type ? I remember a particular prop nut lock which required a specific locking compound for underwater use.

Perhaps they just don't if you tighten them well enough ? (BAd day in store though if they do)

I'm sure I'll get at least one reply that some of the Kong swivels have a locking mechanism (perhaps others too) - but this is what I've got to work with.


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Old 18-11-2010, 16:57   #2
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After getting the proper "locktite" I would look into putting on an adhesive sleeve. That swivel looks nice, but I really don't like my anchor coming loose even on a "lunch break". I definately wouldn't be able to sleep with that.
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Old 18-11-2010, 17:29   #3
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I was told many years ago not to mix stainless shackles (or swivels) on a galvanized chain. Apparently, in the past, there were a lot of commercial fishing boats in this area that broke loose overnight because of this practice with some fatal results. We need to heed the past. Galvanic corrosion of the chain was the cause.

Good rigging practice requires a wire mouse through the eye of regular shackles. However, typically anchor shackles are designed with a hole in the end of the pin that takes a cotter pin to ensure the shackle pin, and nut, is retained. If you overtighten the nut on shackles that have a nut on the end of the pin you run the risk of stressing the pin and shackle. If that pin is stainless there is a greater chance of doing damage since stainless tends to stretch more easily than galvanized steel with resultant corrosion cracks forming that eventually come back to bight you. Never use just `any bolt' as shackle pins are typically tougher and are `proofed' fastenings designed for the loads they must handle.

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Old 18-11-2010, 17:32   #4
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I use locktite on my swivel.
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Old 18-11-2010, 17:59   #5
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I have a similar swivel and I removed the pin and replaced it with a slightly longer pin such that I could screw the pin into the swivel and when tight there was enough thread sticking out to put on a nyloc nut
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Old 18-11-2010, 23:22   #6
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Quote:
Originally Posted by duncan_ellison View Post
Hi anchoring experts

I have a snazzy new SS Anchor Swivel which has two Allen head bolts which are flush when fully in place. similar to this Anchor Swivel

This is going to replace a unidirectional glavanized swivel which is moused with monel wire.

What (if anything) do other members use to stop the bolts coming adrift ?

Should I use locktite ? Any particular type ? I remember a particular prop nut lock which required a specific locking compound for underwater use.

Perhaps they just don't if you tighten them well enough ? (BAd day in store though if they do)

I'm sure I'll get at least one reply that some of the Kong swivels have a locking mechanism (perhaps others too) - but this is what I've got to work with.
The Kongs don't have a locking mechanism, but they should. It's really a complete cop-out to have to use Loctite.

In the inadvisable situation that you have no mechanical locking options, then yes you must absolutely use Loctite / Never-Seez / equivalent, appropriate for underwater usage and resistant to flushing. Re-apply every time you action the pin.

There is no issue with stainless connectors amongst galvanized components. For anything other than permanent submersion it's fine.

Don't mount any swivel directly on the anchor shank.
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Old 19-11-2010, 04:33   #7
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Craig

Thanks for the reply. Like you, I'm inclined to think that Bruce's comment is valid for continuous immersion, but for occasional cruising use, I don't think there would be enough immersion time to be a problem here.

<<Don't mount any swivel directly on the anchor shank. >>

Hmmmmm ... the swivel I have is clearly desigmed with a long throat for this purpose. What's the issue here ?

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Old 19-11-2010, 05:04   #8
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Can someone explain to me the VALID purpose of using this fitting. Its not a true universal, which allows the 360*distribution of alignment forces. If it is attached directly to the anchor stock, and does not swivel into alignment as it comes over the bow roller, it will experience huge, side, distortional loads. It does not have built in facility for safety wiring. How is the swivel male mushroomed(?) inside the female ?
Don't meen to offend anyone, but I tend to get a little bit "nerdy" about this type of thing.
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Old 19-11-2010, 05:05   #9
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They may be 'designed' for it in the sense that it looks elegant and eliminates the need for a shackle, but they're certainly not designed to be true to their WLLs when used in that mode. The failure mode of swivels is almost always when the jaws are levered open by a lateral load, typically during anchor retrieval.

The rated strengths of swivels is for a linear force down their axis, no other scenario.

This is why you don't attach directly to the anchor:

Photo from John Harries.

Failed in gusty winds with boat veering.

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Old 19-11-2010, 05:12   #10
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Can someone explain to me the VALID purpose of using this fitting.
If you mean what's the point of a swivel, it prevents kinking of rode if boat does multiple 360s in some scenarios, and allows the anchor to self-align on retrieval without the chain causing problems (if chain alignment is lost). Some boaters use them because they provide a lower profile connector than conventional shackles, but as above it's inadvisable to use without a shackle anyway. If you don't know you need a swivel, you probably don't.

Quote:
Originally Posted by Blue Stocking View Post
Its not a true universal, which allows the 360*distribution of alignment forces. If it is attached directly to the anchor stock, and does not swivel into alignment as it comes over the bow roller, it will experience huge, side, distortional loads.
True but a bit out of perspective, the loads from the weight of the anchor on the roller are nothing compared to the loads on the rode during use.

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It does not have built in facility for safety wiring. How is the swivel male mushroomed(?) inside the female ?
They are either essentially bolted together then welded to form two single-piece components, or the female section is in two halfs bolted together around your 'mushroom' by the user. In either case, the pin or bolt is vulnerable to mechanical loosening and loss, a not uncommon scenario, unless mechanically stopped. Hence the OP's question re Loctite.
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Old 19-11-2010, 05:16   #11
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Quote:
Originally Posted by craigsmith View Post
They may be 'designed' for it in the sense that it looks elegant and eliminates the need for a shackle, but they're certainly not designed to be true to their WLLs when used in that mode. The failure mode of swivels is almost always when the jaws are levered open by a lateral load, typically during anchor retrieval.

The rated strengths of swivels is for a linear force down their axis, no other scenario.

This is why you don't attach directly to the anchor:

Photo from John Harries.

Failed in gusty winds with boat veering.

Swivels (Rocna Knowledge Base)
Yep!!
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Old 19-11-2010, 05:16   #12
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Craig

Thanks for the reply. Like you, I'm inclined to think that Bruce's comment is valid for continuous immersion, but for occasional cruising use, I don't think there would be enough immersion time to be a problem here.

<<Don't mount any swivel directly on the anchor shank. >>

Hmmmmm ... the swivel I have is clearly desigmed with a long throat for this purpose. What's the issue here ?

Duncan
First -- there is only one locktite to use -- RED, and plenty of it. You will need to heat with a blow torch to remove it (don't recall the temperature, perhaps 300F is enough).

If you're not planning to anchor in one place for an extended period (e.g. more than a week at a time) then just skip the swivel and use a galvanized HT rated shackle of the max size that will fit your chain. You can get those at Welcome To Hamilton Marine . (I use a 3/8" HT alloy shackle WLL rated 2T on 5/16" HT chain also WLL 2T.)

The problem with stainless barrel swivels on the anchor shank is that any large side-loads will cause the shank to act as a lever on the jaws holding the swivel pin, and with enough side-force that will (not "can") cause them to bend apart at the weakest point (the place where the pin runs through). Recipe for disaster: 1) bend 2) stress crack 3) salt water corrosion within cracks 4) failure.

The hinged design you showed is an improvement over the straight version and an attempt to reduce the lever-arm. It can't be fully effective if you analyze the design. If you want to use a swivel like that, you should still run the curved side of a D-shackle through the anchor shank and attach the swivel between that shackle and the chain, so the shackle pin runs through the swivel (or chain if you don't use a swivel). That will eliminate the spreading leverage at the pin. (This is why all anchors are made with an elongated shackle hole -- so the shackle jaws can fit through and you won't be forced to position the pin through the shank.)
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Old 19-11-2010, 05:22   #13
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People use swivels mostly, in my experience, for anchor behavior issues on the roller, not rode kinking while in use. That aside I second the recommendation to go with a shackle unless otherwise required.

The articulated swivel type removes lateral loading from the swivel joint itself but does nothing to deal with the leverage on the forks. They're a waste of time.
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Old 19-11-2010, 05:28   #14
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They may be 'designed' for it in the sense that it looks elegant and eliminates the need for a shackle, but they're certainly not designed to be true to their WLLs when used in that mode. The failure mode of swivels is almost always when the jaws are levered open by a lateral load, typically during anchor retrieval.

The rated strengths of swivels is for a linear force down their axis, no other scenario.

This is why you don't attach directly to the anchor:

Photo from John Harries.

Failed in gusty winds with boat veering.

Swivels (Rocna Knowledge Base)
The swivel in your photo looks like it was bent after the pin was already out, because the bend is below the pin -- so I suspect it was "staged" for illustration. I have one (or had one) that was on my boat when I bought it, that was bent right at the pin, and I expect that weakness would have lead to a failure eventually.

Anyway, your point is effectively made and is welcome: These swivels (if used) should be placed between a conventional shackle and the chain (not attached to the shank) so the load is always straight-line.
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Old 19-11-2010, 05:54   #15
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It wasn't staged, it was a real world failure. There is no reason to expect the fork arm to bend exactly at the pin although obviously it could.

The type above is junk, there is an example in the UK of the same model failing at low level linear tension from stress corrosion cracking across both forks where the pin reduces the section size. In any case the argument applies to any swivel.
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