J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Main halyard/sheaves

I recently replaced all of my running rigging, including changing over from rope/wire halyards to all rope. I did not inspect the sheave for the main halyard as I did not want to go up there on one ancient halyard. As the other sheaves looked OK, I rolled the dice and hoped the main halyard's sheave would be OK.

I think I lost that gamble.

On the first hoist with a new 5/16" Warpspeed halyard, the sail was binding when the head on the main was approximately even with the spreaders. Up to that point, it ran fine. With pressure, it would unbind, however no amount of normal effort would hoist the sail higher.

Whatever was binding the halyard completely chewed the cover off of the new Warpspeed in two spots. Is a sheave capable of that?The wear spots on the halyard are about where it would have contacted the sheave when it jammed.

Is there anything else that would cause that issue?

If it's most likely the sheave, is that something that can be replaced without unstepping the rig, or are they commonly held in with more than just a pin?

Is it a tapered halyard? Or does it have a larger cover added for grip in a clutch? It could be binding at the taper or or where the cover is spliced on. I had to cutdown a bolt that was holding down my windex because I thought it might catch. Maybe it is something like this?

You can replace the sheave without taking down the mast. I got a replacement from Layline a few years ago.

David
#397

[This message has been edited by dbows (edited 08-06-2007).]

[This message has been edited by dbows (edited 08-06-2007).]

Thanks David. The halyard is not tapered and I do not have cover for the clutch.

I suppose it could be something other than the sheave, though I ordered new sheaves from Layline this afternoon.

I haven't been up there for a look. The area rigging ladders aren't tall enough for masthead work.

I think I'll have to have a yard guy go up in a crane, which I hate to do as I won't be able to see for myself what's going on up there.

Whatever it is really did a number on the halyard - the cover is completely off in two 1" sections. What I can't figure out is why it did it just at those two spots (they're about 10" apart). The rest of the halyard has no indication of wear.

I'm going to send the halyard back to Layline to taper. In the meantime, I need to track down the cause of the problem.

I dont know where you are located but in Antigua I was able to raft up to a megayacht and used their electric winches to haul me up to the ht of our mast...then got my crew to lean JDoe to me so I could work on the top of the mast. I also did this with a charter boat in Tortola... You have to be rafted next door but its more stable than being on the top of our noodle... and I had plenty of time to take things apart and put them back together... In fact I plan to do this again when I go back in the water in November

Hey Red, how about coming up to Newport and changing my wind sending unit for me? It went haywire when I was cruising. I was going to get hoisted up to replace it, but you're experienced at this rafting technique!

Bill

Thanks for the advice. I took a look at a J/30 mast that was on the ground today to see how the main halyard sheaves are configured. There are two halyards: one on the mast crane and another inside the mast that's accessed by removing the mast cover plate. Inside the mast is an aluminum housing the runs fore and aft. The sheave has to be replaced by sliding it into place from the underside of the housing.

It would be a lot easier from the ground, but the best price I've got for stepping and unstepping the mast is $600, if nothing slows the process down. That's a lot of bucks to replace $30 sheaves.

I think I'll need a more stable working position than I can get swinging over from another boat. So, I'm thinking of renting a boom crane ($200) and using that to replace the sheaves and inspect the whole rig.

The photos below are of the sheave configuration for those that may find it helpful. They are from the mast I took a look at today, not the mast on Rambunctious.

I had the rig unstepped yesterday to sort out this sheave issue and do some other needed maintenance. I have a write up of yesterday's work along with a number of photos here: http://www.rambunctiousracing.com/mastwork.html

The primary reason for dropping the rig was to find out what was jamming and cutting the main halyard and to fix the problem. I assumed that it was a sheave issue. The real cause surprised me.

The main halyard runs through two sheaves and then drops into the mast. The first sheave is in the mast crane. The second sheave is in the center of the mast. The second sheave serves to guide the halyard down into the mast without chafing on anything.

At some point in the past, the secondary sheave (the one in the mast section) seized. Its bearing was caked with dirt and the sheave would not rotate. Rather than remove the sheave and clean or replace the bearing (which is nothing more than a small bronze sleeve), it was decided to simply bypass the secondary sheave. Bad, bad idea.

Rather than running cleanly into the mast, when the second sheave was bypassed, it ran against the top of the mast extrusion, inside the channel for the mainsail's luff. As it was a wire halyard, it carved a sharp-edged, v-shaped groove in the soft aluminum. Truly, I can't think of a more efficient shape for jamming and cutting line. The photos below show the groove with the messenger line caught in it. With the new sheaves in place, this groove will be bypassed, so the problem is solved. Also, the groove is far too small to have any effect on the strength of the mast.

The two photos below show the groove carved by the old wire halyard:







[This message has been edited by Jason King (edited 08-12-2007).]

Jason,

I am curious, who's mast were you looking at before steeping yours?

I may need your assistance putting my mast together in a couple of weeks.

David Erwin

Yours!

I took a look at it behind Cletus' shop (at his invitation, of course). I called him to see if he knew how the masthead sheaves were configured.

I'd be happy to give you hand; just let me know when and where.

Jason,

Nice work & documentation. I'm pulling the mast after this season to clean it up and repaint it. My NAVMAN wind instrument died a few weeks back and while in Marblehead, David Bows let me borrow his display to see if mine was bad.... unfortunately it was the sending unit at the top of the mast. I went up the mast last week and replaced it with a TackTick wireless. I still need to pull the old wires out of the mast though. Your pictures will help me get ready with sheaves, pins, etc. to do this job efficiently when the rig is taken down. Thanks for the great pictures & descriptions!

Bill