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

[benz]

Hi John,

Antal rings are great for any application where you're not heaving lots of line though under load: I'd not use one for a mainhalyard, for instance. But for your purposes, they're perfect. I run my Stay'sl and jib sheets through Antal rings rather than blocks, and it works perfect (high load/short run).
Ben

[Ian McColgin]

I can see the rings for fairleads and lizards but what's the effect of turning modern cordage through ninety or more degrees over such a small radius?

[JohnV]

Thanks for the replies--
Ben, those gizmos are such a break with tradition that I think most of us--at least true of myself--are hard-wired to overlook them.
Ian, that question was one of the reasons for my post. A bigger radius would be preferable, but in this application, is such a small radius still a problem even though the actual load is static, momentary and infrequent? I don't know the answer to that.
John

[benz]

The small radius won't be a problem for Sta-set, especially since I doubt you're loading to anything near it's working load.
It's neat how many uses there are for very simple things on boats. I think for many years (and still as well), manufacturers have duped consumers into thinking that something more complex must be better. It has been the source of much profit for them, and much unnecessary clutter for sailors.

[Stumble]

Actually modern high tech stuff is less prone to bending issues than older lines. Dyneema has been shown to retain full breaking strength at 1:1 bend:size.

[allene]

Originally Posted by Stumble

Actually modern high tech stuff is less prone to bending issues than older lines. Dyneema has been shown to retain full breaking strength at 1:1 bend:size.

That is not actually true. Dyneema loses half its strength at 1:1 bend radius. You are probably thinking that 1:1 is OK for an eye splice, which it is but an eye has 2x strength of the line so 2 x .5 = 1.

I did some tests with a 90 degree bend and some Amsteel and some StaSet. I lost 20% with the Amsteel and 40% with the StaSet. It is my opinion that low friction rings are really only good with Dyneema or other slippery line. Use a block with double braid.

You might find this interesting.
http://L-36.com/more_low_friction_rings.php

[Stumble]

Allene,

Wow what a dumb mistake. I was looking at the sizing chart for minimum diameter bails for eye splice load not the D/d chart. Thanks for the correction.