Wire block
I am going to make a block for my old Merlin on which the jib halyard goes up around near the hounds and then running back down the line of the forestay around a turning block and then cleated off. In your opinion(s) would a nylon sheave be OK for taking a wire halyard or will I have to get a brass sheave? There is not a vast amount of tension on this - really a wear and tear matter. I have a nylon block so it would save sourcing a metal one!!
there is nylon....and nylon.....some of the stronger vairiants would be fine....but the cheaper ones will fall apart pretty soon.
in my experience, nylon is fine until the block gets sticky and then the wire rips it to shreds in a matter of seconds, potentially in one hoist of sail....so if you go with nylon you really have to keep checking that block is nice and loose.
It also has to be totally straight as if the wire is coming down over the side of the nylon, then again it won't last long.
Personally....as it is for your nice boat (arn't they all) you will never regret the work taken to find a brass one.....but will always be annoyed by a plastic bit!
cheers
eib
in my experience, nylon is fine until the block gets sticky and then the wire rips it to shreds in a matter of seconds, potentially in one hoist of sail....so if you go with nylon you really have to keep checking that block is nice and loose.
It also has to be totally straight as if the wire is coming down over the side of the nylon, then again it won't last long.
Personally....as it is for your nice boat (arn't they all) you will never regret the work taken to find a brass one.....but will always be annoyed by a plastic bit!
cheers
eib
Ed Bremner
CVRDA
Jollyboat J3
Firefly F2942
IC GBR314 ex S51 - 1970 Slurp
MR 638 - Please come and take it away
Phelps Scull
Bathurst Whiff - looking for someone to love it
CVRDA
Jollyboat J3
Firefly F2942
IC GBR314 ex S51 - 1970 Slurp
MR 638 - Please come and take it away
Phelps Scull
Bathurst Whiff - looking for someone to love it
Have to agree with Ed, except that I don't think even best quality Nylon will cope for very long. Of course, if you don't plan on much rig tension, you could use Spectra (Dyneema) for your Halyard and solve the problem that way. Not sure it would look right, though, having plastic fittings on the foredeck!
Rupert
I have to confess to a small pulley block in black plastic at the foredeck level but then there will only be about a foot (30cm) of wire running through that as the halyard will be wire spliced to rope (the gospel of Merlin according to Chris). But up the mast where you can't see what's going on is another matter as it would be wire all the way and doing a 360 degree turn the nylon is likely to get minced. Last year I had an all rope halyard in red and it really looked naff.