Low friction ring vs block

[UNCIVILIZED]

Finding sheaves is fairly easy, & even a search of CF will turn up plenty of sources for them. Including places where you can have custom ones turned for you, for $25-$50 each. And of course bolts are cheap.

Strictly speaking, those aren't turning blocks. But if they've worked thus far, there's little reason to change them now, unless you find some true turning blocks, cheap. And low tech blocks aren't tough to make, as can be seen from how these are built. If you decide to DIY fab' a pair yourself.

If you truly want a becket, you're probably best to build larger, longer side plates for the existing blocks, & keep the bolt in the sheave's axle. That, instead of trying to use a shackle through it's axle. Or, add a 2nd set of side plates to the block which start at the sheave's axle, & extend out past the sheave. Where you'd then have a seperate bolt for the becket's head.

[Compass790]

You could get sheaves from another manufacturer probably if you send them the dimensions from yours they miight have something close enough

[Opie91]

Try these guys out. They can build just about any sheave you like:

Zephyrwerks - The Sheave Factory

Pretty reasonable pricing too. I have used them several times.

[StuM]

Originally Posted by Dockhead

I am a big, big fan of low friction rings, but I would not use them for that application.

They are superb for any line which doesn't move much, OR where there's not much angle of deflection. A turning block -- where you have miles of sheet running in and out AND with a large angle of deflection -- is exactly the wrong place for them.

You want a nice ball bearing block for that. Which means biting the bullet and paying the cost.

My thoughts exactly.

[ramblinrod]

Originally Posted by Markhunter1097

I need to replace my turning blocks for my 70 sqm genoa, they are excellent Schaefer 12series stainless blocks, that have now just worn out.
Rather than spend the approx $1000 each to replace them, I was thinking to use low friction rings instead.
Apart from not looking right, is there any other reason not to use them?

There's no such thing as an excellent Schaefer block. Furlers are OK, but blocks are feeble. Go Harken. Properly sized and appplied, you will never need to worry about them in your life time.

[Training Wheels]

35. Just did a rough count of the number of low friction rings in use on my boat right now. I will be adding a few more, though.

[Training Wheels]

Oops, make that 37!

[Training Wheels]

Um... 38!

[Markhunter1097]

Originally Posted by Training Wheels

35. Just did a rough count of the number of low friction rings in use on my boat right now. I will be adding a few more, though.

Training Wheels, obviously you like rings. Do you use them in the application I have suggested? What issues, if any, have you had with them?
thx

[Training Wheels]

I do love the low friction rings. They're cheap, strong, light, and maintenance free. However, they're best used on low load lines that will be adjusted frequently, or high load lines that once tensioned, are seldom adjusted. I would not suggest using them on a jib sheet lead. I do use then around my jib sheet for my barber hauler, though.
The previous advice given on this thread is sound. Don't use them on high load lines that are adjusted frequently.

[Dockhead]

Originally Posted by ramblinrod

There's no such thing as an excellent Schaefer block. Furlers are OK, but blocks are feeble. Go Harken. Properly sized and appplied, you will never need to worry about them in your life time.

I agree actually.

Harken are great. The Lewmar ball bearing blocks are also very good, as are the Wichard ones.

I have these:

Lewmar 130mm High Load Single Footblock | MAURI PRO SAILING

Bulletproof and excellent. Rated for 6 tons (!) safe working load. 15 years of hard use and still flawless. Cost less than $500 each and worth every penny.

The Harken ones are probably even better.

Good deck hardware is key! Don't compromise! Spend your money on sails and deck hardware and ropes first; then think about what to do with what is left over, if any

[Dockhead]

Originally Posted by Training Wheels

I do love the low friction rings. They're cheap, strong, light, and maintenance free. However, they're best used on low load lines that will be adjusted frequently, or high load lines that once tensioned, are seldom adjusted. I would not suggest using them on a jib sheet lead. I do use then around my jib sheet for my barber hauler, though.
The previous advice given on this thread is sound. Don't use them on high load lines that are adjusted frequently.

They're fine for jib sheet leads, and are often used for that on racing boats.

Your advice is good except they are ALSO good when the angle of deflection is small, AND they are good when the line runs through them without much load on, as jib sheets while tacking.

High load lines, frequently adjusted are also fine -- as long as you don't have great lengths of lines going through them under load. That's when the friction catches up with you.

There are actually very few applications on board where they are unsuitable. Unfortunately for the OP, a sheet turning block is one of them.

[Dockhead]

Originally Posted by Training Wheels

Um... 38!

Hah, and I thought I had a lot You've got me beat by a lot.

I have 6 in use for my blade jib twing system, 2 more for the inhaulers, 2 for barber haulers, 4 more for a tackle I used to use for lifting my dinghy, that's about it so far.

[UNCIVILIZED]

Originally Posted by Dockhead

Good deck hardware is key! Don't compromise! Spend your money on sails and deck hardware and ropes first; then think about what to do with what is left over, if any

Who are you, & where is Dockhead (the old one)?

Harken rocks, BTW! Always has

[Training Wheels]

+2 for Harken!