Low Friction Rings

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Neeves

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I had a thread on LFRs a few months ago - this is picking up on a comment made by someone who appeared to have actually used them.

I recall, possibly inaccurately, that what was said that the orifice, the hole in the centre of the ring, through which the working rope passes, should be 50% larger (and maybe larger still) than the rope itself.

I wondered the reasoning behind this - and any other comments on the relationship between rope and the size of the LFR.

A secondary comment was on the materials used for LFRs. Most appear to be made from an aluminium alloy (the 7075 alloy? as it is hard, and then hard anodised. How does the anodising stand up - and the what happens when the aluminium alloy is exposed. And finally - does anyone have any comment on using polished stainless for an LFR.

I'm thinking of an application where the rope is turned almost back on itself and constantly doused in seawater. I have an infinite ability to size the LFR, it can be as big as I want (I have them custom made) and can be hard anodised aluminium or stainless. Movement of the rope through the LFR is not great and does not need to be instantaneous. Then rope is nylon (for its elasticity). I have been using both hard anodised aluminium and stainless LFRs - but don't really have the long term exposure - so am seeking the experiences of others.

This is a novel application - that works surprisingly well , so no need to suggest that turning through 300 degrees, with nylon, is not ideal (it works) - I'm looking for a short cut to better focus next year's usage :)

Jonathan
 
What's the question exactly?
I think the answer's about 1.6.

In my experience, LFRs are light and trendy.
They do somethings quite well, other things half as well as a block at twice the price.
The anodising wears off.
The ropes going through them wear, but that's OK because bimblers love changing rope.

I thought the anodising was PTFE-soaked, but that might be wishful thinking on my part.
You can also apply wax or PTFE or your favourite snake oil to the rope.
 
One of the questions, now, is - why 1.6. Why not 2 - or is that because they are extortionate? Or is there a technical reason - like they look ugly if too big :)

I agree that they are very trendy, must haves - a bit like soft shackles

Jonathan
 
alahol2 said:
I use them for the lazy jacks. It was so long ago that they were just called stainless rings (and probably cost about 1/10 as much as an LFR). They work exceedingly well.
Click to expand...

That's the same as how I did mine. I also threaded a line through the lower rings back to the mast so I could pull that line to pull the lazy jacks toward the mast. The prevents the main sail to jamming when raising. They stay at the mast to reduce chafe on the sail and only bet released when I with to drop the main into the stat pack.
 
Rogershaw said:
That's the same as how I did mine. I also threaded a line through the lower rings back to the mast so I could pull that line to pull the lazy jacks toward the mast. The prevents the main sail to jamming when raising. They stay at the mast to reduce chafe on the sail and only bet released when I with to drop the main into the stat pack.
Click to expand...

I don’t have a stack pack, but yes, that’s my intention.
 
For some years I just had 30mm plastic rings on my 34M2 mainsail lazy jacks. Now I have 25mm SS ones. i do not see the point of 10 * 80mm ones which are just a lot of weight swinging about aloft. The line hardly moves through them once set. My lazy jacks work perfectly well. Rarely get in the way & once set stay set all season.
 
Should hold up reasonably well. I've used them on bobstays. Like your use, the near unbreakability of LFRs has considerable value in some applications. A block with the same WLL is generally huge and $$$.

There will be a lot of friction. As much as 30% of the tension will be lost around the bend.

I suspect they do bad things to double braid rope. The friction will try to milk the cover.

The diameter ratio is probably even larger. The general 1.6:1 minimum (more is better) recommendation is for Dyneema single braid. I've used then with polyester DB, and you really need a greater radius than Dyneema.
 
I'd think for lazy jacks, plastic rings would do the job fine.
Or another cheap trick I've used is to splice an eye, with the eye part of the line covered in adhesive-lined heat shrink.
It's cheap, easily done and fairly low friction. It's also painless to sit on, doesn't damage anything etc.
I've used it on things like the system which tidies up the slack in control lines.
I intended to use PTFE tube instead of heatshrink, but it didn't 'fall to hand'.
 
Hopefully not tons, but certainly 100s of kgs.

I had threaded LFRs made, same design, same size, in both anodised aluminium and polished stainless. The costs were surprisingly similar. The stainless versions, 316, look stunning the aluminium ones (anodised in black, not my choice - you get what you can for small lots) look pretty boring. In terms of use - I cannot see the difference. My aluminium ones were made in the same factory used by Ronstan (so mine are Ronstan black). The stainless ones feel substantial, the aluminium ones 'feel' less robust.

It is amazing how weight influences ideas. Maybe that's why aluminium anchors have a bad press.

Under tension there is lots of friction and the ropes don't move, though they may slowly creep or maybe more accurately - slip.. If you remove the tension they will then move, noting I am turning through 300 degrees. Having said that I had them under tension for around 8 hours - and they did not move - even though the tension one side was different to the other. this, maybe, has implications for lazy jacks that might be under tension on a large sail (depends on the functions of the lazy jacks (ours originally also replaced a topping lift and ours used little shackles (before LFRs were fashionable). We now have a topping lift and still use the small shackles (works fine).

My rings are obviously a bit small for the ropes I am using, hence the question, and I need to have bigger ones made - and it sounds as if I should go larger than 1.6 - maybe 2 times. I'm also thinking of making the length of the shaft (very short normally but longer when threaded) to be a bit longer - and then instead of a turn through 300 degrees I'll have 2 turns of 150 degrees). I might also think of sleaving the rope with a dyneema cover for critical locations.

Slippage of the cover over the core is another issue (that same issue with dyneema halyards).

I was concerned at the anodising wearing off - it sounds as if it might be an issue - though whether it impacts performance I don't know. Stainless seems to be a better option.

Jonathan
 
Would the diameter of the material the ring is made of make much difference? A larger section would be kinder to the rope and may be easier to pull with the rope being turned round a larger radius? Is there a recommended maximum angle a rope should be turned through a ring, not turned back on itself but at a wider angle?
 
Lucy52 said:
Would the diameter of the material the ring is made of make much difference? A larger section would be kinder to the rope and may be easier to pull with the rope being turned round a larger radius? Is there a recommended maximum angle a rope should be turned through a ring, not turned back on itself but at a wider angle?
Click to expand...
People commonly use them turning the rope 180deg in a cascade tackle.
Not sure about 300degrees, that's turning it into a climber's descender. Where friction becomes a 'good thing'.
Other applications are more about deflecting a rope a little, such as a barber hauler or spinnaker guy tweaker.
There is much friction within rope when you turn it through a tight radius relative to its diameter. So people use the thinnest dyneema which is strong enough. I think that some thin lines with non-braided, parallel filament cores taking the load can be best.

But every application is different. On my boats, I use anything from a lorry rope hitch to a Harken block, whatever does the job well enough.

'1.6' was just a random number in my first post BTW, like the meaning of life being '42'.
 
LW395 - the 1.6 was a joke, I, now, know, but I did not laugh.

Much of what you had said previously in this and other threads has a degree, had a high degree ,of credibility

Anyone who sails a LW395 , in my book, commands respect - its a twitchy, high performance yacht that is exhilarating if sailed well

Suddenly, in my book, you have undermined your own position.

Well done.

Unfortunately your figure of 1.6 did appear to fit with a figure quoted by another member here of 1.5, or 50% larger. Now we understand your idea was a simple fiction.

Thanks for having the honesty and integrity to own up.

People read these threads and accept them as near gospel, maybe (if it is possible) you can amend your original post. sadly people do not red all of a thread and your post and your, fictional, 1.6, are the gospel and until you modify the comment, it is cemented - with your name - in the ether.

Other people make unsubstantiated comments - and don't have your integrity - I can commend you, but I can also understand how 'internet truths' develop, that are not truths.

I'll get off my high horse now.


In the, my, application for the LFRs the high friction under high load is actually advantageous. I want to understand, or learn, about usage (as I have no, zilch, experience of using LFRs, which is why I asked).

Jonathan
 
Last edited:
lw395 said:
I'd think for lazy jacks, plastic rings would do the job fine.
Or another cheap trick I've used is to splice an eye, with the eye part of the line covered in adhesive-lined heat shrink.
It's cheap, easily done and fairly low friction. It's also painless to sit on, doesn't damage anything etc.
I've used it on things like the system which tidies up the slack in control lines.
I intended to use PTFE tube instead of heatshrink, but it didn't 'fall to hand'.
Click to expand...
Yes nylon thimbles are what I used, just a few pence each. The spicing was covered with heat shrink electrical insulating tube. Quick, easy, cheap; Which Was What Was Wanted or 'W5' as my old maths teacher used to say.
 
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