12 replies to this topic

[quasi-expert]

here is one for the carbon/composite gurus

our whole rigging is connected to the mast with eye terminals and stainless steel pins.
Would it be possible to replace them with carbon rods?
can carbon cope with the shear stresses?

[sailman]

The short answer would be no, carbon's high properties are in tension and compression. The pin would be relatively large compared to it's stainless counterpart.

[bammiller]

We just made up 4 barrel pins out of 13-8 stainless steel; probably could knock 50% of the diameter out of them, compared to 316 stainless, especially after they are hardened. A bit pricey though.

Bam Miller
 IMG_2677.JPG   289.41K   23 downloads

[quasi-expert]

The short answer would be no, carbon's high properties are in tension and compression. The pin would be relatively large compared to it's stainless counterpart.

Thanks for the link. Pretty useful for quick estimations.
But IMO one important information is missing to evaluate this. All the data regarding the shear refer to the fabric plane (so IMO the given shear strength is a result of the resin used, not so much the fibre). For a UD carbon pin the strain would be vertical to the fibres. Anyone have data for this loadcase?

[quasi-expert]

We just made up 4 barrel pins out of 13-8 stainless steel; probably could knock 50% of the diameter out of them, compared to 316 stainless, especially after they are hardened. A bit pricey though.

Bam Miller
 IMG_2677.JPG   289.41K   23 downloads

The diameter would have to remain constant to use the old rigging. I just thought this would be an easy way to save weight aloft as UD rods are pretty cheap (~20$/m for 8mm).

[sailman]

The short answer would be no, carbon's high properties are in tension and compression. The pin would be relatively large compared to it's stainless counterpart.

Thanks for the link. Pretty useful for quick estimations.
But IMO one important information is missing to evaluate this. All the data regarding the shear refer to the fabric plane (so IMO the given shear strength is a result of the resin used, not so much the fibre). For a UD carbon pin the strain would be vertical to the fibres. Anyone have data for this loadcase?

Shear is still shear though.

[Overbored]

Look at it this way. I can shear of a piece of 8mm carbon rod with a wood chisel and a light blow with a hammer. try this with a 8mm stainless steel pin. carbon pins are just plastic with the carbon as reinforcement and the shear strength of either does not change when you cover the carbon with the plastic..if you want to save weight then go to titanium. in racing, he who spends the most money wins.

[vmg]

Carbon is not good with abrasion, the pin will wear very quickly

[Remodel]

here is one for the carbon/composite gurus

our whole rigging is connected to the mast with eye terminals and stainless steel pins.
Would it be possible to replace them with carbon rods?
can carbon cope with the shear stresses?

No, this is a bad idea.
How is that for succinct?

[BFD]

Sure you can use the carbon pins. Just make sure the insurance is paid in advance and have lots of video cameras around the first time you go sailing. Make sure to post the video here. We will enjoy the show.
PS You might want to issue hard hats to the crew and be more than one mast length to weather of any other boats in the area.

[Oxygen Mask]

in racing, he who spends the most money wins.

Does money spent on beer count?

[pickles]

Didn't some boating magazine in theuk use fiberglass rod as rigging pins to try and break the rig and didn't they in the end have to use a lot smaller fiberglass pins in the end to make it fall over? There was a video of it.

I would not recommend it though!

[Presuming Ed]