Main Halyard mast roller

[Shaneesprit]

Hi
I have an issue in that my Halyard is ridiculously heavy, please do not suggest an electrical fix.
I believe the issue is that at the top of the mast there is a single small roller so effectively turns the halyard 180 degree to lift the sail from a boom roller reef.
Any suggestions?
Boat is 25ft Cat halyard is actually suffering the strain, Halyard 12 or 14mm thick from memory and has 2 x 90 degree rollers at deck level.

[psk125]

Change the sheave? It could have gotten worn on its bearing and be jamming. Sheaves that are made out of plastic can also fail, essentially disintegrating. This leaves the halyard chafing over a clevis pin or bolt at the masthead. The halyard may also have jumped the sheave, so that it is stuck between the mast and the sheave. Time for a look-see at the top of the mast, or time to unstep the mast and investigate that way.

[Cheechako]

Yes on inspecting the sheave it may be frozen. But why are there two 90 degree blocks at the bottom?
If you just lift the main by the halyard (not through those two bottom sheaves), is it easy?

[Shaneesprit]

Originally Posted by Cheechako

Yes on inspecting the sheave it may be frozen. But why are there two 90 degree blocks at the bottom?
If you just lift the main by the halyard (not through those two bottom sheaves), is it easy?

2 x 90 one to take halyard from Vertical to horizontal and the other to direct it from Stern to Port through the block to the winch. One nearest the mast failed under the pressure and has been replaced.
Roller boom can be turned by hand, the sail track is a concern but not sure it’s that. plus no idea where to find another.
Last time I inspected the sheave (didn’t know what it was called) it was ok although admit the halyard has become heavier - I was more thinking it might it would be better to have 2 sheaves to get a true Vertical pull on the main rather than it sitting a little behind or a larger one but not the easiest place to pop up and have a look.

[Cheechako]

Originally Posted by Shaneesprit

2 x 90 one to take halyard from Vertical to horizontal and the other to direct it from Stern to Port through the block to the winch. One nearest the mast failed under the pressure and has been replaced.
Roller boom can be turned by hand, the sail track is a concern but not sure it’s that. plus no idea where to find another.
Last time I inspected the sheave (didn’t know what it was called) it was ok although admit the halyard has become heavier - I was more thinking it might it would be better to have 2 sheaves to get a true Vertical pull on the main rather than it sitting a little behind or a larger one but not the easiest place to pop up and have a look.

Yeah, a larger diameter sheave is always better if possible.

[Shaneesprit]

Originally Posted by Cheechako

Yeah, a larger diameter sheave is always better if possible.

It’s the possible i am trying to work out.
Most modern masts have a T shaped top hat, where I only have the vertical.

[Cheechako]

Originally Posted by Shaneesprit

It’s the possible i am trying to work out.
Most modern masts have a T shaped top hat, where I only have the vertical.

You mean with two sheaves? Yeah.
I suppose you could have a new masthead made. Not sure it's worth that though.
Have you tried just pulling the halyard only from below, to see how easy it it without it through the bottom two? .... as a test?

[Jim Cate]

OP, are you saying that you roll the sail around the boom when striking it, and then need to un-roll it, rotating the boom, when hoisting?

If so, I'd suggest changing the procedure to flaking the sail on the boom when lowering. The added friction of having to rotate the boom is not insignificant, even if you can move it by hand when nothing is going on. I suspect that there is considerable friction added when the sail is the force that causes the rotation because it loads the bearing in the boom rather differently than in your simple test.

You might try experimenting with hoisting a weight with the halyard... substituting a friction free load for the load presented by the sail's weight, the friction in the mast track and the rotating boom. Should help decide where the problem lies!

Good luck with it.

Jim

[maine50]

A 12mm (or 14mm?) halyard is pretty big for a 25 cat. Is it original? Try using a smaller line even if you have to borrow one. The top sheave may not be the right size and causing all sorts of friction.

[Shaneesprit]

Originally Posted by maine50

A 12mm (or 14mm?) halyard is pretty big for a 25 cat. Is it original? Try using a smaller line even if you have to borrow one. The top sheave may not be the right size and causing all sorts of friction.

That’s a sensible thought / Advice although I doubt it, my thought is never to dismiss an idea but to prove it wrong, so I will certainly try this when I have time - don’t expect a quick reply.
Is it original - no way it was replaced with like for like a few years ago, but that wasn’t original either.
and it’s only a rope so I am sure I can just buy a few meters.
I don’t like rope to be less than 12mm, poor handling but now I want to compare all of my running rigging with other similar boats.

[Shaneesprit]

Originally Posted by psk125

Change the sheave? It could have gotten worn on its bearing and be jamming. Sheaves that are made out of plastic can also fail, essentially disintegrating. This leaves the halyard chafing over a clevis pin or bolt at the masthead. The halyard may also have jumped the sheave, so that it is stuck between the mast and the sheave. Time for a look-see at the top of the mast, or time to unstep the mast and investigate that way.

From memory while hanging in the chair it’s a metal sheave but small in diameter

[psk125]

Originally Posted by Shaneesprit

From memory while hanging in the chair it’s a metal sheave but small in diameter

Could easily have gotten worn out of round and/or need lubricating.

[roverhi]

12mm line is way oversize foe a 25' boat. Wouldn't be surprised if the masthead sheave was sized for 5/16" line spliced to 3/16" wire. That would mean a lot of side friction if the line is too large for mast head opening. I'd seriously consider 5/16" dacron outer sheath line with a Dyneema core and you might find it way easier to raise that sail. That's what i'm running on my 28' monohull and 3/8" on my 35' boat.

[Shaneesprit]

Originally Posted by maine50

A 12mm (or 14mm?) halyard is pretty big for a 25 cat. Is it original? Try using a smaller line even if you have to borrow one. The top sheave may not be the right size and causing all sorts of friction.

Thanks
Took me ages to find this thread, but owed you some thanks for that great 👍 suggestion.
I guess as the halyard got worse as it got older too.
Lashed in a temporary smaller line and it lasted the rest of the season. Unfortunately pulling in its replacement the two separated and I have to go up the mast.