Shackle bending

I suppose it depends on how the shackle was manufactured. If it was originally shaped hot, further heating may not change much. If it was cold forged originally then heating to reshape it may cause softening and reduce it's strength, depending on the temperature it gets to. Iirc, re-heating grade 300 stainless steel is not always a good idea because it can increase probability of pitting and intergranular corrosion.
 
Neeves said:
I cannot tell from your picture but I assume the 2 shackles are the same size, simply a different width.

The original shackle has clearly demonstrated it was of adequate strength (it was well, over, specified originally), its possibly been cyclically loaded and the fact that it lasted 40 years should give you comfort that the new shackle should last as long. I suspect it is unlikely you will keep the yacht for another 20 years (unless you were 10 years old when you bought the yacht) - stop fretting and go for it.

You will need to over bend the shackle to compress to the size you need, I'd do it slowly (bit by bit) as you don't know how much over bend you will need - it will spring back. I'd do it in a vice with wood in the 'slot' and wood either side of the shackle, to protect the shackle from any possible point load in the jaws. I'd have the whole shackle in the slot, not just the crown. When you squeeze the shackle just make sure it is in the vice 'square' and does not pop out (and hit you). I assume there is a shackle pin 'inside', the thread will now not be long enough - you will need to extend the thread. I would not use the old pin - it will have been stressed even though you might not see any evidence.

Whereas it would be interesting to know why the original failed the damage may have been caused, much, earlier - maybe you can recall some disaster that befell you 18 years ago - and have all the precise details?

Sorry nothing new here - I'm just reiterating good advise already posted.

I just wish other sailing kit would last as long as your failed shackle - imagine having an anchor chain, sails, halyards with a life of 40 years! I've had shackles fail, not unlike yours, supplied and specified by Ronstan and they lasted a few years.

Jonathan
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Do not bend or attempt to reshape the shackle.
Shackles are made in the various dimensions that is length, diameter, thickness etc, not by accident but by engineering design, to suit a particular purpose.
DIY adjustment for a variety of reasons, heated or not, the very act of doing so itself changes the manufacturers desired final construction.
To think of this shackle as just a piece of randomly arranged metal is very wrong.
Worse I would consider is the approach that it is fine as it should last you the rest sailing life?
What about considering the next owners life?
And for what.... a few £’s in finding the correct one.
 
VicS said:
But surely you cannot harden or soften 300 series stainless steels by heat treatment as you can with plain carbon steels because the FCC austenitic structure, only stable at high temperatures in carbon steels, is stable down to room temperatures .

.
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OK ... I'm not so expert ...

I still don't like the idea ...
 
It's a strip shackle.
Cold stamped out or maybe even drop forged and then bent to the required dimensions that just happen to be a bit wider than you need.
Bend it a tadge more! Live life dangerously!:)
Come on all you experts and tell me I'm wrong and that the boats going to sink if you you "adjust"it slightly.
?
 
Your right, fitting a shackle in the full knowledge and afore thought that is possibly dangerous (unnecessarily endangering others lives) is the same as crossing the road? Do you do so with ears plugs and a blindfold? Or knowingly when dangerous to do so?
This dreadful crossing the road analogy trotted out once again.
More akin would be if you arrange your brake fluid to slowly leak prior to doing long motorway journeys, has the same dangerous element, not knowing when your going to need the fluid leaking away, as to when a deformed shackle is going to give way.
 
greeny said:
It's a strip shackle.
Cold stamped out or maybe even drop forged and then bent to the required dimensions that just happen to be a bit wider than you need.
Bend it a tadge more! Live life dangerously!:)
Come on all you experts and tell me I'm wrong and that the boats going to sink if you you "adjust"it slightly.
?
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Fair enough but given the amount of cheap Chinese items on the market - are you so confident. Brand label is no longer any guarantee of quality .... given the outsourcing prevalent today. I prefer not to tempt the gods.
 
Adjusting the throat of a shackle is not unknown ... but the amount that I consider safe - is an eyeball ratio of the original throat.

One post says its only 3mm ... well my answer there is - 3mm is nothing on a large shackle - but is significant on a shackle as this. It could be enough to cause minute fracture lines in the upper U of the throat - with potential for another break.

The fact that the old shackle has fractured and broke as shown in photo - says to me that a force was applied that overcame the shackle. It does not appear to be corroded or worn down ..

Sorry but in the interests of good order - I would source a correct sized shackle .. or as I posted earlier - MACHINE the slot to fit the new shackle.
 
Personally I would squeeze the shackle slightly and put in position and use. I suspect that getting a shackle to fit the old IYE is impossible nowadays, as presumably the traveller is imperial size and the shackle metric. Maybe the slots on the traveller could be widen but that may then cause other problems.
May be the old shackle just gave up after 40 years ?
You mention interesting results when the shackle failed. In what way ? There is only a few people looking at this forum ..................
 
Yes and luckily some with an understanding of engineering.
Perhaps a word with a manufacturer, if there isn’t an acceptable quorum here for you, would clear matters up. I feel convinced their reply would be an honest one with a reputation to defend rather than motivated by the sale of a single shackle as some may infer.
 
So what do the more risk averse members think the op should do when he spends the next few weeks not sailing, trying to source one that fits and then finds he can't source the correct size shackle for his 40 yr old traveller. Buy a complete new track and traveller?
Or maybe apply good judgement and skill and buy a decent shackle and bend it slightly to fit.

"Practical Boat Owner's reader to reader"? I do wonder sometimes. :)
 
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