Low Friction Rings

[thinwater]

Thanks, that's useful for predicting friction in LFRs, but it's the effect on internal friction in a rope caused by varying the radius of a sheave that I was interested in.

Obviously, that depends on...

• material
• size.
• construction. double braid, parallel core, webbing, and single braid are very different.
• age
• presence or lack of internal lubricants (which can be renewed)

The variation will be huge.

 

[lw395]

Obviously, that depends on...

• material
• size.
• construction. double braid, parallel core, webbing, and single braid are very different.
• age
• presence or lack of internal lubricants (which can be renewed)

The variation will be huge.

Any rope with a braided cover, the stiffness and friction through blocks can also change according to the tightness of the cover relative to the core.

 

[anoccasionalyachtsman]

I'm only interested in the rope we'd normally use through blocks. I'm sure it's been done before, but possibly not with the newer types.

 

[thinwater]

I'm only interested in the rope we'd normally use through blocks. I'm sure it's been done before, but possibly not with the newer types.

^^ To "L395," yes, the tightness of the cover and the hardness of the lay matter. Hardlay can be very stiff. A tightly covered but soft climbing rope can fly through blocks. It depends.

^^ to "anoccationalyachtsman," all the types I mentioned run through blocks. All of these could be asked to run through LFRs, and sometimes are.

• Double braid is ubiquitous.
• Parallel core is common in halyards.
• Single braid is common on halyards and sheets, with the cover stripped off the forward part. Double braid with the core removed (very common in furlers) handles much like single braid (because it is single braid).
• My cunningham is Dyneema webbing; it glides through eyes more smoothly than rope.
• All materials are valid (not aramids--they don't flex well through blocks or LFRs). I have them all on my boat, each according to what it does best.

 

[lw395]

^^ To "L395," yes, the tightness of the cover and the hardness of the lay matter. Hardlay can be very stiff. A tightly covered but soft climbing rope can fly through blocks. It depends.

^^ to "anoccationalyachtsman," all the types I mentioned run through blocks. All of these could be asked to run through LFRs, and sometimes are.

• Double braid is ubiquitous.
• Parallel core is common in halyards.
• Single braid is common on halyards and sheets, with the cover stripped off the forward part. Double braid with the core removed (very common in furlers) handles much like single braid (because it is single braid).
• My cunningham is Dyneema webbing; it glides through eyes more smoothly than rope.
• All materials are valid (not aramids--they don't flex well through blocks or LFRs). I have them all on my boat, each according to what it does best.

Aramids are OK!
You better believe it if you uses lifts or is that elevators?

 

[thinwater]

Aramids are OK!
You better believe it if you uses lifts or is that elevators?

Man-lifts too. True enough if you can stand the LONG radius they use on the pulleys. Not LFRs. I've seen aramids fail from fatigue.

 

[Neeves]

My thought, practising what I preach, that maybe a row of LFRs could be used as a boom brake, or preventer. Lace cordage through the LFRs which are inserted into a simple perforated (for the LFRs) plate. Use the inherent friction as a boom brake or preventer with some give.

There are similar devices already on the market, they are used in climbing -

Just Blue Skying.

Jonathan

 

[zoidberg]

There are similar devices already on the market, they are used in climbing -

Climbers' Figure-Of-Eight 'descendeurs' are effective used as boom brakes, and an order of magnitude cheaper than the almost-as-effective chandlery products.