Pung boy

29er Trap Shackle

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Hello everyone

 

Have just acquired a 29er for our son, so this is all a rather daunting and new to us.

 

Was looking at the top section of the mast where the shackle attaches to that little Plate’ which in turn is connected via a through bolt. I have noticed that the bolt on that shackle has been rubbing on the mast and caused a small indentation into the carbon. Which is why is has been wrapped in electrical tape (tattered and loose) around the shackle. Is there any way of reducing that wear? 

 

 

 

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It's been a while but I don't recall doing anything other than wadding it up with some tape. 

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Oh ok, thank you. I was thinking about putting in a slightly longer bolt and adding two washers instead of the one. Trying to push out that bracket further away from the mast slightly. 

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On 12/16/2020 at 9:23 AM, Pung boy said:

Oh ok, thank you. I was thinking about putting in a slightly longer bolt and adding two washers instead of the one. Trying to push out that bracket further away from the mast slightly. 

The further away from the mast you put the tang the more likely you are to bend the bolt.

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Yes, that’s true. But I’m only thinking about an extra washer width. Which will be and extra 0.5-0.75mm on each side. I’m sure that wouldn’t be too bad would it?

 

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So I made these up today. I call them Aston Sleeves’ they are made from 8mm alu tubing. I used a small pipe cutter to get the 5-6mm length. They sit in the shackle to stop it gauging out the carbon. I have made a up a few sets of them as the probably wont last that long. But who cares, easy to make and crazy cheap. They work by stopping the shackle from sliding past half way, which also helps keep the loading on the pin centred. Anyway the spares sit in an empty pill bottle, which can be taken with you and changed out anytime.

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Are you doing anything to separate the aluminum from the carbon fiber? They'll react otherwise. 

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Do you think that would be an issue? I’m unsure, would that size matter? If it would then I could swap it out for something else. 

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So to the best of my knowledge, you may now use a T-Ball there.

If you secure the Key-plate in place "securly" with a electrolysis inhibitor, and then use a T-Ball your problem is goooooooone.

                jB

nb1, before the inevitable, I sail on a few yachts with 20 year old carbon masts with SS fitting which are attached with mulitpule SS bolts tapped in using a inhibitor, and there is no sign of electrolysis on any of the masts.     Do it right and it works.

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I would have to check (can't do that now, boat is away for winter), but my recollection is that I have a much "flatter" schackle there (ie pin is shorter), therefore  no rubbing between the pin and the mast.  As I never changed them, either they came stock on the (very) old boats like mine, or the previous owner made the mod. Your solution is elegant, but as warned above I would worry also about the electorlyse between the alu tube and the ss pin => I had done something similar to fix the wing extension "XX rig" style to the gunwales, and a few years later  impossible to remove the bolt from the sleeve, they had "soldered" together.

cheers

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14 hours ago, JulianB said:

So to the best of my knowledge, you may now use a T-Ball there.

If you secure the Key-plate in place "securly" with a electrolysis inhibitor, and then use a T-Ball your problem is goooooooone.

                jB

nb1, before the inevitable, I sail on a few yachts with 20 year old carbon masts with SS fitting which are attached with mulitpule SS bolts tapped in using a inhibitor, and there is no sign of electrolysis on any of the masts.     Do it right and it works.

Thank you.

can someone please explain what a T-Ball is (only had the boat a week, and come from another dinghy) so we can search that up. I’ve just found some SS Tubing as well, so could go with that too.

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image.png.691aa00b8ae5fd518956a63f3c727590.png

Std T-Ball, this one is Bluewave (Danish)

image.png.24f76196228f6fbb6ed020343519d792.png

And this is the Bluewave keyplate, but the one you would use in a lot simpler.    This one take many tonnes where you only want 100kgs max.

The shackle people are refering to is a Ronstan RF614

image.png.a4b5eaacffbbc45ccaf080659fb3c5f0.png

We have had them up to 3 tonnes, stupidly simple and stupidly strong.

Enjoy,  jB

 

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I'd make the sleeves out of some unbreakable plastic. Hard PVC (the grey stuff) ist easy to work, largely good enough for your purpose and no corrosion.

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I have noticed that using T terminals for trapeze wires often ends up with a wire failure at the lower end of the terminal stage due to friction in the socket not allowing the t terminal to not immediately align with the wire causing fatigue in the same place over a period of time. This was particularly noticeable in International 420s using 2mm trap wires, it was even worse on the rigs using hooks for the trap wires.

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