Failure of 316 D Shackle

[Rogue Wave]

Originally Posted by Polwart

Stu - are you suggesting that every shackle the leisure boater uses should be tested and certified? This shackle was being used in place of a hook on a trailer winch - not for some lifting operation. The original hook was probably not individually certified, nor I suspect will the bow eye it was connected to.

You pays your'e money and you takes your choice! But yes that's the way I'd go if possible.

If you've ever had a winch strap fail on you whilst under load then you'll know they find their way to your head area very quickly, If that shackle failed but was still attached to the strap when it came to meet your face it could be serious. I've always overspecced my straps shackles cos I like to take my risks on the water not on the slipway.

I don't think snap shackles are very good at all and prefer to replace them with proper shacles or Carribaeneers mmm Shiney.

By the way my buddies who have known me a long time call me lucky stu, cos when the stuff hits the ventilation I'm normally standing close by so I have learnt to be cautius

But in my world if it ain't tested then it's worthless and I have found that out the painful way. 1 would suggest that going the extra expense for tested harware to me sems a very sensible use of budget

[jwalker]

Originally Posted by Rogue Wave

If you've ever had a winch strap fail on you whilst under load then you'll know they find their way to your head area very quickly, If that shackle failed but was still attached to the strap when it came to meet your face it could be serious.

I agree and I use carabiners for winch rope connection just for ease of clip on but I use two of them, one on a short extension rope so if the first should fail the second will hold back the released rope.

That shackle looks like a flexing stress crack and there looks to be a piece missing too. Stainless is very poor at flexing and easily cracked.

[Simon B]

All the shackles I've used for towing etc have a safe working load on them. If they havent dont use them. A lot of eBay cheapy jobs simply have the material spec 316 - food grade (I think).

A cautionary tale! If used with cable or a rope that stores a lot of kinetic energy they are lethal.

[Searider]

Good macro photo of the fracture surfaces needed to give an opinion on how / why it failed.

[Bigmuz7]

Originally Posted by jwalker

looks to be a piece missing

Agreed .. but it can look deceptive, without a repositioning to tell

[Pikey Dave]

Last year, one of the square "U" bolts that secures the winch post to the drawbar on my 1 year old SBS trailer failed whilst I was recovering the boat on a steep slip in France. The boat, post & winch went south with a bang, the winch nearly took my fkn head off Since then I have reviewed every part of the boat & trailer that is subject to load, particularly anything that has the potential to release a lot of energy sharpish. I would NOT use anything, especially in the winch area, that was not rated. Sorry if I sound a bit preachy, but the incident scared the sh1t ot of me.

[Bigmuz7]

Originally Posted by Pikey Dave

Last year, one of the square "U" bolts that secures the winch post to the drawbar on my 1 year old SBS trailer failed whilst I was recovering the boat on a steep slip in France. The boat, post & winch went south with a bang, the winch nearly took my fkn head off Since then I have reviewed every part of the boat & trailer that is subject to load, particularly anything that has the potential to release a lot of energy sharpish. I would NOT use anything, especially in the winch area, that was not rated. Sorry if I sound a bit preachy, but the incident scared the sh1t ot of me.

I think thats actually a good point, in that a lot of trailers are set up by the boat yards them selves when a boat is sold as a new craft, or placed on a different trailer, and IMO the trailers I've had , have been very poorly configured, and not correct for supporting the boat at all, and in particular some of the u bolts and check plates have been severely over torqued and have been deformed so much I have ended up replaceing some of them, because they will already have been weakened.

Similarly, such poor set ups and poor support by way of roller placement etc, have lead to poor towing experiences, and have had implications for loadings in the events of emergency stops etc, or resulted in excessive drawbar bounce when under way for example,.. so I think its good practice to have a logical think about the way the boat sits on the trailer, and to examine mountings for weakness or over tightened bolts, or rusted through ones for that matter, because as you say, there could be nasty consequences, even with fairly new kit