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Wet Spreaders

Cracked Tylaska

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Hmmm - this is an odd breakage. Lucky we found it before it gave way on the other side too.

 

IMG_0071.jpg

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Looks as though its seen a bit of life.....

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Yes. I can’t recall the last time I replaced it. I’m more interested in the asymmetry of the crack than the lifetime - which I can’t complain about. 

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What was it being used for and how big were the loads compared to what the shackles were rated for? I'm interested as the rig on my boat depends on a couple of them.

Tylaska seems pretty responsible about their products. Have you contacted them?

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looks as if the eye has been stretched before it failed , looks like the loads where way over design .

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Farr 30 (Mumm 30) uses a Tylaska T5 per class rules. That boat has a displacement of 2069 kg and similar size spinnaker.

J105 displacement is 3500 kg. So the J105 has a much higher righting moment (similar draft bulb type keels) and thus higher potential loads.

Tylaska suggests T5 are "ideal for J-24, Mumm 30 and similar boats"... I'd say the T5 is a bit undersized for this boat. I'd step up to a T8 or similar higher breaking load..

 

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Several years ago, an employee stole a bunch of Tylaskas from the factory before they went through final inspection.  Tylaska offered to inspect/replace for free.  They wanted to be sure to protect their reputation as to the quality of their product.  I'm betting if you contact the company, they will replace it.  

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WS I’ll second that the shackle has appearance of uneven load unless it’s deformed similarly on the other side. Let us know what Tylaska has to say, if you would 

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any chance it got hung up in the guard/bale that is in front of the 105 spinnaker sheave? This would cause some uneven loading. 

Fully agree that a T5 is a little small for a 105, especially sailing in SF

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Hmmm.... the uneven loading might do it. We had a wrap about 3 regattas ago in a blow (full on forestay/jib entanglement with the kite halyard eased a little)  that might have done it if the Tylaska was bent across the forestay tang or something like that. It can't get into the kite bale because I have a ball on the halyard to stop that. 

I expect someone with metallurgy experience could tell if it was simply overstressed or fatigued. That would be interesting to know.

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Not a metallurgist, but a semiconductor engineer, who looks at far too many Failure analysis reports... 

Your crack seems to have propagated from some etch pits, that may have been aligned to the stamping of the "T". 

Depending on the Tylaska process, the stamping may have been done as a "Quality" mark at the end, or in line. As such, if it was post heat treatment & polishing, then it would break the surface passivation layer, and be a  focal point for stress corrosion cracking, as well as a retention of moisture (note that the lettering, and various scars are all showing corrosion) 

It's a bit surprising that the failure point occurred in a larger section than the smaller  which is closer to the "..ka" though if the loading were against the small bump that houses the pin, you might have had a force that would put the crack in tension, and the smaller sections just in deflection. 

Seems to be a bit of either corrosion or deformation near the pivot pin, which would lend credence to a failure mechanism of the head ring lodging there. 

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Can't really ask them to replace it if you've under speced it. Either suck it up and get another t5 for the weight reduction whilst being away of their life expectancy or put up with the extra weight and spec it correctly to a larger unit. 

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1 hour ago, Alcatraz5768 said:

Can't really ask them to replace it if you've under speced it. Either suck it up and get another t5 for the weight reduction whilst being away of their life expectancy or put up with the extra weight and spec it correctly to a larger unit. 

I agree - the unit had been in use for a long time and did not actually fail (never dropped a sail) - I'm not interested in torturing Tylaska for a replacement. I'm more interested in figuring out what happened - whether accident, underspecced, wear-out mechanism etc -  than complaining about the part, which did its job well for a long time. The crevice corrosion idea around a stamped logo is an interesting hypothesis.

Overall, and based on the feedback, I should probably fit the T8 as the replacement. The tiny extra weight aloft probably does not matter on the downwind legs anyway.

 

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  Most of the Tylaska & Sparcraft (before them) failures involve cracking around the axle pin. I'm pretty sure your shackle got trapped with a side load on it.

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On 5/29/2018 at 12:01 PM, LionessRacing said:

Not a metallurgist, but a semiconductor engineer, who looks at far too many Failure analysis reports... 

Your crack seems to have propagated from some etch pits, that may have been aligned to the stamping of the "T". 

Depending on the Tylaska process, the stamping may have been done as a "Quality" mark at the end, or in line. As such, if it was post heat treatment & polishing, then it would break the surface passivation layer, and be a  focal point for stress corrosion cracking, as well as a retention of moisture (note that the lettering, and various scars are all showing corrosion) 

It's a bit surprising that the failure point occurred in a larger section than the smaller  which is closer to the "..ka" though if the loading were against the small bump that houses the pin, you might have had a force that would put the crack in tension, and the smaller sections just in deflection. 

Seems to be a bit of either corrosion or deformation near the pivot pin, which would lend credence to a failure mechanism of the head ring lodging there. 

I don't think so.  To me, it looks a lot like the the break started at the edge of the wear spot created by the SS ring from the kite combined wit some tourqing by being side loaded.  Below the break is also the bottom of the fork cut out for the hinger at the end of the shackle so another obvious point for a crack to start.. There would be no way Tim would be silly enough to stamp anything after heat treating the shackles

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