Clevis pins substitute?

[Daydream believer]

The pins I would now use a tab on one end with hole the is bolted to the plate to hold it in without a split pin and to prevent the pin rotating

Bolt through the hole in the tab

So what stops the 2 plates separating?
Or is this another expensive complicated F U by "engineers" to justify their existence?

 

[rogerthebodger]

So what stops the 2 plates separating?
Or is this another expensive complicated F U by "engineers" to justify their existence?

First This arrangement would be used where a fork type connecter is used as on lifelines and wire rigging that I used on my backstay using a single triangle plate with for end in the rigging wires

The Blue wave shown by yhe OP is a costly way of using a triangle divider plate . You only need one plate of a thicker material to dothe same job as I did at my backstay connecting at the top of my mast and mot halfway down the single backstay

Hence Rotex comment about Engineers can do to 50 pence what would cost a pound done you others

This type of rigging fitting I have all over my boat we know the split ring can be pulled out and so the clevis pin can the fall out and don comes the rig.

Welf a tab on the ecistig pin and drill and tap a hole in one side of fork and secure the pin in without any snag points.

The fork end on hydraulic cylinders do have a spring attached to the clevis that clips into the round screwed section as below

what you must understand is the Engineering designer and Production Engineer need to design and make components the most cost-effective way especially when large number of the same component are needed as an extra 10 pence on the manufacturing cost eats into the profit of the company.

Where only one or two are manufactures cost per item is not such an issue.

You also need to loke at the loading of the item and is there a way to change the design to make manufacturer simpler and cheaperwith out affecting the functionality and reliability.

All I did was to demonstrate various ways of designing different ways of clevis pins design. Nut and bolt being one of them

 

[Poignard]

Neeves said [post #2] :

"Split pins do catch sails but quite why your sails are going to get wrapped round the back stay is a question you might ask yourself".

That's the question I ask too.

I can't imagine any circumstances where any part of a mainsail, or mizzen, would touch a backstay.

The only type of backstay I can think of that comes into contact with a sail is a running backstay, and that is not what the OP is talking about.

Is the OP perhaps looking for a solution to a problem that doesn't exist?

 

[zoidberg]

Is the OP perhaps looking for a solution to a problem that doesn't exist?

Just a poor example....

Split pins do catch on things and slice them - f'r example, fingers.

Should I chose to use bolts I'll use locknuts. Should I use clevis pins with holes, I'll use aviation-standard wire locking.

 

[Daydream believer]

Should I use clevis pins with holes, I'll use aviation-standard wire locking.

But is putting the wire through the split pin hole is actually the correct use of the wire? I understood that the wire was to go through correctly torqued nuts etc. to help retain them. Placing the wire against a moving plate, or fork, or whatever does not sound right. This is because it can wear through the wire as the face of the retained part will move against the wire as the clevice moves. There is a shearing action between the retained part & the hole the wire goes through. It stands to reason that it will never be a tight fit so there will always be room for movement .
Plus, I am not sure that buying a large quantity of specialist wire for a 6 inch length is really worth the bother. Unless one has a source of small quantities.

 

[Neeves]

Just a poor example....

Split pins do catch on things and slice them - f'r example, fingers.

Should I chose to use bolts I'll use locknuts. Should I use clevis pins with holes, I'll use aviation-standard wire locking.

Your backstay plate should not need much or any attention. I don't see why you cannot smother split pins with silicone or amalgamating tape. If you do need to take it apart silicone or amalgamating tape is easy to remove. Similarly you don't need nyloc nuts you can use Loctite, blue, but you could use red as the backstay plate will not need attention.

You are unlikely to wrap a sail round the backstay plate and if the plate is high enough you will not be able to reach it (and/or) if you use wire - 3 pieces of wire is likely to scratch hands or tear sails (and be less secure).

I'm still not sure how, why a sail will get wrapped round the back stay plate any way.

You must be getting old and are starting to worry far too much.

Jonathan

 

[Stemar]

I had a similar setup on my Snapdragon, but with a single plate and the wires ended in the kind of fork Rogerthebodger illustrates above. Clevis pins with split pins. It was never an issue, even though I used the plate as a cleat to make off my ensign halyard. I don't think I ever disturbed it in the 18 years we had the boat, as I'd disconnect the stay from the chainplates when taking the mast down.

 

[zoidberg]

First This arrangement would be used where a fork type connecter is used as on lifelines and wire rigging that I used on my backstay using a single triangle plate with for end in the rigging wires
You only need one plate of a thicker material to dothe same job

I agree - that would be a more efficient approach.

Had I been starting 'from a clean sheet' I'd most likely have adopted that. However, I had the existing rigging-wires simply copied and replaced. These had swaged eyes. Only recently have I been looking askance at the existing 'twin triangled plates and clevis pins' arrangement and thought it underspec'd.

 

[rogerthebodger]

I agree - that would be a more efficient approach.

Had I been starting 'from a clean sheet' I'd most likely have adopted that. However, I had the existing rigging-wires simply copied and replaced. These had swaged eyes. Only recently have I been looking askance at the existing 'twin triangled plates and clevis pins' arrangement and thought it underspec'd.

Starting with a clean sheet does make it easier. Pictures of what you currently will help to recommend various way using what you already have

The suggestions that I made are just various different designs I have used in the past mainly when making new and all have advantages and disadvantages. You need to use which one suits you and the current setup.

 

[thinwater]

Just a poor example....

Split pins do catch on things and slice them - f'r example, fingers.

Should I chose to use bolts I'll use locknuts. Should I use clevis pins with holes, I'll use aviation-standard wire locking.

I think this is an interesting point that merits discussion. I've done this a few times (turnbuckles), generally when original clip is gone, the cotter pin is not usable. A few thoughts:

• Cotter pins are NOT designed for re-use. Once they have been bent once the chance of cracking goes up. But we've all done it.
• New split rings (corrected) are not subject to snagging. Old split rings (corrected) that have become spread can snag. We should (but don't) carry a small bag of rings to replace them every few uses.
• Locking wiring breaks too. Often, this is do to incorrect installation (over tension and too tight twists). Like soldering, most people have not been trained.
• Shear strength. A safety wire is only to prevent rotation (turnbuckle or nut). A cotter pin may be expected to carry some shear load, which wire is less well suited to, even with many passes. The size of the hole is a clue. The pin or wire should mostly fill the hole.
• IME monel is easier to work with and more reliable around seawater than SS. WM used to carry it, but SS is cheaper and thus easier to sell at a profit.

And there are endless youtube videos showing incorrect ways.

In this case, the problem is that he is missing a washer and that his cure is not manufacture recommended. Add the washer and the fit will be correct!

Aviation wiring. Do NOT over tension or over twist.

Please discuss.

---

Side note. The leading cause of dismasting on most trailerable boats is some variation on pin failure, simply because they are designed to be quick. Split pins are are relatively fast, but after use become spread open enough to snag.

 

[penberth3]

• New split pins are not subject to snagging. Old split pins that have become spread can snag. We should (but don't) carry a small bag of rings to replace them every few uses.

---

Side note. The leading cause of dismasting on most trailerable boats is some variation on pin failure, simply because they are designed to be quick. Split pins are are relatively fast, but after use become spread open enough to snag.

I don't understand what you're saying here. In use, the legs of split pins are spread or turned back anything up to 180 degrees. There's always potential for snagging on the ends of the legs, new pins or re-used pins, it makes no difference.

Can you explain what you mean?

 

[thinwater]

I don't understand what you're saying here. In use, the legs of split pins are spread or turned back anything up to 180 degrees. There's always potential for snagging on the ends of the legs, new pins or re-used pins, it makes no difference.

Can you explain what you mean?

I miss-typed. I meant to say split rings. My bad, I apologize.

New split rings are tight and difficult to snag, but with use they open up. Also, some are made with bend ends to make them easier to open. Good ... and bad.

Cotter pins weaken with repeated bending. They are intended for single-use ... but we all reuse them sometimes. You should keep a pile of replacements on-hand. You won't see a good rigger re-use them.

My point is that re-using split rings and cotter pins can be hazardous.

---

But the topic I was hoping to start was about the viability of wiring in some of these cases. I believe (let's discuss) that some applications could be either, but some really need the strength of a pin.

 

[thinwater]

Bump.

How do you decide when a cotter, split ring, or wire, or other is best?

• Strength and wear. Cotter or split ring. Not as good as threads, but something. Note that shackles secured with cotters instead of the threads are not rated for side loads. Not for controlling rotation, but can if they will strike something or with castellated nuts (cotters).
• Snagging. New split rings and wiring are good. But wiring takes some training and will generally be weaker than a cotter.

Also note that cotters and rings are most snag-prone when they are worn or installed incorrectly. Always point cotters down. Don't spread the legs to far, unless only one is carefully bent over a bolt end. Also, trim to length; extra does not really help. Stuff mechanics know.

Actually, wiring is just to prevent rotation, not to provide shear restraint. Or am I wrong?

[Those that have described using MIG wire or similar are a different, interesting case. Seems like a great answer for turnbuckles.]

Round Pin Shackles can be used in tic down, towing, suspension or lifting applications where the load is strictly applied in-line. Round pin shackles should never be used in rigging applications to gather multiple sling legs, or where side loading conditions may occur.

 

[Neeves]

Bump.

How do you decide when a cotter, split ring, or wire, or other is best?

• Strength and wear. Cotter or split ring. Not as good as threads, but something. Note that shackles secured with cotters instead of the threads are not rated for side loads. Not for controlling rotation, but can if they will strike something or with castellated nuts (cotters).
• Snagging. New split rings and wiring are good. But wiring takes some training and will generally be weaker than a cotter.

Also note that cotters and rings are most snag-prone when they are worn or installed incorrectly. Always point cotters down. Don't spread the legs to far, unless only one is carefully bent over a bolt end. Also, trim to length; extra does not really help. Stuff mechanics know.

Actually, wiring is just to prevent rotation, not to provide shear restraint. Or am I wrong?

[Those that have described using MIG wire or similar are a different, interesting case. Seems like a great answer for turnbuckles.]

Round Pin Shackles can be used in tic down, towing, suspension or lifting applications where the load is strictly applied in-line. Round pin shackles should never be used in rigging applications to gather multiple sling legs, or where side loading conditions may occur.

If your clevis pin is a bit, or worse, a lot too long then the split pin (if that is what you are using to retain) will stand proud and will be an issue. The first thing you need to do is ensure that hole (for whatever you are going to use for retention) is flush with the plate in which the clevis pin is used. Clevis pins appear to come in standard sizes, diameter and length. They tend to be cheap - so its worth having a cross section of sizes. But if the clevis pin is too long you might need to cut it back (angle grinder) and drill a new cotter pin hole flush with the plate through which the clevis pin is housed.

If the cotter pin (split pin) is housed flush to the 'device' you can bend the legs only slightly and then silicone flush to the surface of the device. I find the cicular cotter pins, the ones like as used on a key chain, can be fiddly to open, especially in the dark on a wet night but are a good answer for small blocks. Small split pins are also difficult to manipulate (and easy to drop/lose).

I don't think there is a one size fits all - horses for courses both split rings and split pins have their places.


Shackles don't have a place now in the lifting industry - there are far superior options. Lifting assemblies are commonly made up using a master link with 'connectors' namely Omega links or Hammerlocks.



The master link and the connectors will be the same size, generally 6mm and larger, and same specification G80, G100 and G120. Commonly it is physically impossible to use an, say, 8mm connector with a 6mm or 10mm chain - they simply will not fit (unlike a shackle). Much lifting equipment is colour coded, all yellow or all red - so you can see at a glance that everything matches. The size, specification and WLL is commonly part of the lifting device all forged into the surface.

Sailing/Yachting components are in the dark ages - a stainless shackle is defined only by size and even that can be a guess, is it 3/8th" or 10mm and no-one has any idea of its WLL nor even what specification of stainless it is made from. Alloy shackles, bow shackles are called 'Anchor' shackles in the lifting industry, are an exception - they will be marked with size, commonly imperial, WLL and maybe a batch code. There are few quality bow, anchor shackles, Crosby, Peerless, Campbell (larger Van Beest) and Yoke. Really the only application for alloy shackles is in the rode and because you can use any chain (almost) with any shackle mismatches are common place. The photo below shows the problem - its common place (but keeps anchor makers in business)





A 3/8th", Yoke, G80 shackle with a WLL of 2t - all clearly marked. The shackle also has a batch code.


There is little point in securing (neatly ? ) your bow, anchor, shackle with wire if you don't know its, the shackle, specification - in this case the pin pulled out of the threaded eye, the wire did what it was meant to do, but the anchor was lost.


Jonathan

 

[zoidberg]

'But wiring takes some training.....'

Faulty wire locking very nearly killed me, and my pilot, when a plug on a hyd reservoir at ~3000psi came out in flight - followed by nearly all the hyd fluid on the Puma helo.
That a/c was supposed to be completly uncontrollable without hyd services. Both he and I learned something that day...

The wire-locking had been done using an approved tool by a qualified aero-technician - then inspected by another, more qualified, and signed off. It should not have been possible, but it came undone.

My pilot was awarded a neat little medal for his efforts - and a fair few beers from me.

It wasn't my job to inspect wire-locking, but I did make it my task to learn how - and what a duff job looked like.

 

[Neeves]

Faulty wire locking very nearly killed me, and my pilot, when a plug on a hyd reservoir at ~3000psi came out in flight - followed by nearly all the hyd fluid on the Puma helo.
That a/c was supposed to be completly uncontrollable without hyd services. Both he and I learned something that day...

The wire-locking had been done using an approved tool by a qualified aero-technician - then inspected by another, more qualified, and signed off. It should not have been possible, but it came undone.

My pilot was awarded a neat little medal for his efforts - and a fair few beers from me.

It wasn't my job to inspect wire-locking, but I did make it my task to learn how - and what a duff job looked like.

It would be almost complimentary to call my example Post 34 as 'duff' but the failure, not mine, was actually caused by a poor choice of anchor shackle - presumably sourced from the nearest hardware store (rather than failure of the wire securement).

Inappropriate shackles choice is common place, with inevitable results, this one is/was a member of YBW and lost a Rocna anchor


I was giving a lecture on ground tackle at Manly, near Brisbane, and the owner gifted me his failed shackle, the one in Post 34. He had just bought an appropriately sized Anchor Right Excel, I'm guessing around 25kg, roughly stg600 - lost because he did not pay stg10 for a shackle.

If you are N Am based all of the manufacturers I list (for G80 alloy shackles) have a US base, you can buy Crosby shackles from Tecni in the UK and Yoke have recently opened an office, also UK. Peerless and Crosby are now all part of one large company and you might be able to source their shackles through Gunnebo (another section of Kito Crosby). Yoke have distributors in Australia (but they are pretty useless with a focus on lifting) and I buy direct from Taiwan. Campbell, part of Apex Tools, are also N Am based. You can buy reasonable alloy shackles from a few reliable Chinese manufacturers - but they want to sell 100s, not 2 so are not so easy to work with.

Jonathan

 

[Neeves]

Shackles are 'different' and split pins or rings don't come into the equation - so Thinwater's mention and my detail is a bit of thread drift. For shackles, anchor shackles, I'd be happy with Loctite - but Loctite really is not a replacement for a split pin - different requirement. Loctite can replace wire (or used as well as wire)

For a discussion on split pins/rings then a simple bolt and nut comes into the equation - with the nut being a Nyloc nut or secured with Loctite.

Jonathan

 

[Stemar]

Now I'm concerned, because I don't know the provenance of my anchor shackle. What conditions caused the failures in posts 34 & 36?

 

[Neeves]

Now I'm concerned, because I don't know the provenance of my anchor shackle. What conditions caused the failures in posts 34 & 36?

Take a picture of your shackle, one of each side. Post here.

You anchor shackle should have a means to identify who made it. They are usually embossed with the manufacturers name, the ones I list. If there is no name it has probably never been tested (and if it was tested it would be found to not meet the WLL stamped on the shackle - been there done that).

The shackle that bent was insufficiently strong. The shackle that broke apart similarly - for different reasons. Both may have been side loaded (which would reduce their WLL).

There are 2 problems - all 3/8" shackles look the same - though many are missing some or all of the embossed details. 3/8th" shackles are commonly available from any hardware store - excellent for securing a dog, an accident waiting to happen if used in the anchor rode. Many are marked WLL or 1t or 2t (common specifications for 3/8th" shackles) - but are actually not tested rigorously. Grade B alloy 3/8th shackles from the manufacturers I list will have a WLL of 2t, are sometimes described as G80 shackles. You can source 3/8th" shackles with a WLL of 1t, these shackles might be rigorously tested but if side loaded at 45 degrees have a WLL of 3/4t and if side loaded at 90 deg have a WLL of 0.5t - so why would you buy one when you can source a 2t 3/8th shackle so easily (Tecni in the UK or other sources). A 3/8th" shackle will commonly be used with a 8mm G30 chain which has a WLL of 750kg - side loading the shackle means the shackle is the weak link.

I omit CMP Titan from my list - they make a Black Pin shackle - the 3/8th" version is said to have a WLL of 2t (Imperial). I would not buy one, once bitten twice shy. You can source a 3/8th" shackle in the UK, mail order, easily (again Tecni) - why would you take a risk for a couple of Stg....? For completeness here is a link to CMP Titan shackles High Strength, Forged, Hot Dipped Galvanized Shackles - I reiterate I would not buy them and would priorities sourcing from Crosby, Peerless, Yoke, Campbell. CMP are the same people who make the Rocna anchor.

I am sure there are other sources, other than Tecni, of 3/8th" shackles with a WLL of 2t that are reliable but being based in Australia its difficult for me to search...of UK sources.

This is a link to the Crosby shackles that I am describing. Bow not 'D' shackles, bow through the shank, pin through the chain.

Crosby® 209A Alloy Screw Pin Anchor Shackles | Crosby®

Note they make an almost identical shackle with a WLL of 1t.

You will note that the smallest shackle that Crosby make is their 3/8th" shackle. Peerless and, I think, Yoke make smaller shackles to the same quality. Gunnebo, a Scandinavian maker of lifting chains is now owned by Kito Crosby and may stock some Crosby components, or be able to access them. I think Gunnebo have a UK office. Kito now own Peerless Peerless | Peer-Lift® Screw Pin Anchor Shackles. Yoke have recently opened an office in the UK https://www.yoke.net/english/wb_product02.asp?url=032&cid=138&nid=66. You can buy Campbell shackles, 'Orange Pin shackles', from US distributors, Defender - not sure if they do mail order to the UK - but commonly American are not interested in offshore sales and prices are prohibitive. If you have friends relatives in the US.... Link to Campbell grade B alloy bow/anchor shackles 5410695

Most shackle failures are caused by the operator, using a shackle too small, not wiring the pin nor using Loctite (better - wire and Loctite ). You would be unlucky to load, even, a nefarious shackle at 90 degrees. But with a bit of application it is not difficult to source a decent shackle - and removes one weakness in your rode.

If you use 6mm chain you can upsize the chain by adding a 6mm G100 hammerlock or Omega link. You chain will be at best a G70 chain, more commonly G40, or even G30 - the G100 link you source (any supplier of lifting kit) will be stronger than the chain. You can then fit a 3/8th" shackle. These links will not be galvanised - buy 2 and when the first one is a bit grotty retire it and use the new one (and buy another 2). Omega link and Hammerlocks are cheap, relatively. The link you retire you can clean and paint and it will be ready for another day.

Jonathan

 

[Neeves]

If you do use 6mm chain and the anchor is smaller than 15kg then a hammerlock works well, once you get it all connected. A 6mm hammerlock will fit a small anchor quite neatly (though may not fit a 15kg anchor and 6mm chain). There is a bit of trial and error needed to get everything that fits and is the appropriate strength, made slightly more difficult as anchors of the same weight from different manufacturers have a different shackle hole size in the shank.

Unlike shackles Omegas and Hammerlocks are bit of a faff to assemble but once fitted are secure (and are usually neater than a shackle). Disengaging an Omega or Hammerlock needs a punch and hammer (you can buy punch sets quite cheaply). The locking in pins on Omegas usually need to be drilled out but then you can punch the clevis pin out but you need to bodge up an anvil to rest the connector on when you punch out with the punch pin (I used a big old socket resting on a chopping board but now have a piece of 12mm steel plate with a 10mm hole drilled right through).

Jonathan

A 10kg Viking with 6mm chain and a hammerlock connector