Converting to synthetic standing rigging, what to do about the D2s…

[fxykty]

Originally Posted by Benz

A closed thimble with Dyneema shroud...
This is DM20 with an Dyneema cover, but DUX will go on it as well.
Thimble cost about $8 USD at US Cargo Control.

An open thimble like that is OK for a smaller boat like yours and relatively low loads. That kind of thimble will be crushed by the loads on a 44 foot boat. That’s why thimbles designed for synthetic rigging are solid.

[fxykty]

Originally Posted by The Yacht Rigger

Thanks, all good feedback. Yeah we are working on expanding the size range in the US. Already have some rope eyes that will take up to 16mm. Other fittings to follow.

Good to hear. We have 18mm DUX shrouds and there’s nothing for us from Blue Wave. We had to go Colligo when we made the change to synthetic four years ago. Plus, what about covered shrouds?

[The Yacht Rigger]

Originally Posted by fxykty

Good to hear. We have 18mm DUX shrouds and there’s nothing for us from Blue Wave. We had to go Colligo when we made the change to synthetic four years ago. Plus, what about covered shrouds?

Thankfully the Blue Wave design allows for covered shrouds already, currently our challenge is developing something in a similar style that allows for the larger line sizes without the weight getting out of control. We already have aluminum fittings, but they get pretty large to keep the strength up there.

Testing is underway with a new design. Hopefully we bring something to market in the next 6 months. The great thing about Blue Wave is the engineering team is always ready to try out new designs for us.

[Benz]

Originally Posted by fxykty

An open thimble like that is OK for a smaller boat like yours and relatively low loads. That kind of thimble will be crushed by the loads on a 44 foot boat. That’s why thimbles designed for synthetic rigging are solid.

No it won't. It's meant for wire rope pulled to the rope's break load.

Unless you have crushed one yourself, or can show published engineering data, please don't muddy the waters.

[s/v Jedi]

Originally Posted by Benz

No it won't. It's meant for wire rope pulled to the rope's break load.

Unless you have crushed one yourself, or can show published engineering data, please don't muddy the waters.

Likewise, you should show the citations to back your claim.

[Benz]

Originally Posted by s/v Jedi

Likewise, you should show the citations to back your claim.

From the vendor:

" the strength is equal to the wire rating they are intended for."

I asked this specifically about the thimbles I'm using, and are in the picture.

[Lee Jerry]

Originally Posted by s/v Jedi

... So Lee Jerry is right (he normally is )

Ha! Thanks, but maybe you could tell that to my wife and kids.

[Lee Jerry]

Originally Posted by fxykty

An open thimble like that is OK for a smaller boat like yours and relatively low loads. That kind of thimble will be crushed by the loads on a 44 foot boat. That’s why thimbles designed for synthetic rigging are solid.

A couple thoughts:

The typical purpose built ones for synthetic rigging (like from Colligo) are aluminum. The one(s) Benz referenced is SS. The modulus of elasticity of SS ~3x that of aluminum, which for the same shape makes them three times stiffer (stronger?).

If it were to fail, as you say, it would simply elongate, putting some slack in the shroud but shouldn't be catastrophic with the mast coming down (at least not immediately).