J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Halyard Loads

I'm wondering if you guys know how much load our haylards (and uphaul) need to be able to handle.

Looking at the equipment and line i'm currently using, I'm guessing that sheaves and line that could handle 700Lbs working load should be good for a replacement spinnaker halyard.

I also want to replace my uphaul sheaves, and I'm guessing that they should be ok with significantly less (even though the recommendation seems to be 3/8" line).

Check out this old thread for a good discussion on loads.

Thanks Bill,

Since the spinnaker doesn't generate lift the same way the foils do, I can't use the formula they talk about there to calculate spinnaker loads. I sent harken an email asking for info. Using the compu-spec tool for a J/30, they recommend a mast base block with a working load of 792 lbs, which is in-line with what I was guessing. Disqualifies that harken ball-bearing sheave everyone's been talking about...

-g

I emailed harken about the sheave loads, and here's what they gave me:

> Halyard sheave blocks are going to see a little more load because they turn at a greater angle. I would think the spinnaker halyard sheave would see just under and the jib halyard just over 1,000 pounds maximum working load.

It is really a non issue, though, because as far as I can find, rig-rite is the only place selling replacement sheaves that'll fit my jib-box. They need to be 31/64" wide...

Find an approprate oversize sheave and a friend with a lath or a small machine shop and make it fit instead of giving money to a business that doesn't seem to care about serving their customers. There are no suppliers in the middle of the Pacific ocean.
Last flingiv-Hawaii

31/64 is seriously precise measurement ... you sure its not half inch? don't think Kenyon worked to that level 30 years ago. now everthing is confused by metric options.

Unless of course a PO revamped your mast.

http://rigrite.com/Spars/SparParts/Sheaves.html#2

I tried to put a harken 1/2" sheave in my pole lift exit block (which uses the same sheaves as the jib halyards) and it wouldn't fit. It also had a much smaller OD which would have required me to drill a new axle hole in an impossible location.

search the rigrite link you sent me for "K-198-8A". This is the top spin halyard sheave.

-g

so OK ... is a wire grove what you are looking for?

or does their

2" Nylatron Sheave - 31/64" wide, 3/8" ID: K-11638:
Heavy-duty Nylatron Sheave is 2" OD x 1/2" (.484") wide x 3/8" ID. As used on Kenyon Jib Boxes, K-11590 and K-11591 (upper Sheave), and in other applications. With Rope Groove.

work for you?

I think there is a move away from wire ...

if you are talking .016 in. as a problem oversize ... you could sand it down?

I was just pointing to that sheave to illustrate the size precision. I have wire halyards right now, but plan to move to rope when I replace them.

Also, I found a local company that custom cuts delrin sheaves: http://zephyrwerks.com/. Their prices are competitive and the guy was pretty nice and helpful on the phone. I'll post some photos whenever they come in.