Boom preventer: Antal low-friction ring vs turning block opinions?

[allene]

I just read the original post again. You want to make a boom preventer by going from the boom end to the foredeck and back to a winch. I have tried this using StaSet and it didn't work for me. The problem was the stretch of the line. Work out the geometry yourself calculating the total length when prevented and the total length it would have to stretch to to flip to the other side. Part of the problem is that this geometry has a lot of "gain" or leverage on the load so your line is going to be heavily loaded and thus stretch a lot. I would suggest you use dyneema for most of the preventer and splice some staSet just for the last bit. Use interlocking eye splices. That is what I ended up doing.

That said, the ring is fine. I use my foredeck cleat as the turning block.

[JohnV]

Thanks to you all for your thoughts.
Re: the stretch that allene mentioned, I'm using sta-set x in order to reduce stretch, and the portion of the line from the boom to the foredeck is Amsteel blue.
I will research more the effect of such a sharp, low-radius turn in the line before I make up my mind. The times this system will be put to hardest use will be to withstand a sudden and significant load from a back-winded 353 sq ft mainsail, so I guess the numbers will have to determine my course forward.
I've also seen that Colligo sells a similar part to Antal's that has a larger radius.
Thanks again for the help with this.
John V.