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

I need to replace the Main Halyard Sheaves. Does anyone know where I might find drawings or dimensions for them? I have a crew memeber who is machinist that is going to make them out of Stainless Steel with Ball Bearings pressed in. Would like to only have to go up the mast one time to remove old and replace new.
Capt Bob

here are photos of current model available from Rigrite. Which I am supposed to change out but am having trouble finding a rigger here who has enough insurance to work at city dock.

I am thinking they just might be the same size as the turning blocks at the base of the mast. at least that would make engineering sense that all sheaves on the mast be the same size and all the pins the same size.

but then maybe that is too optimistic. also note they are grooved for wire.

I would look at this thread.

https://j30.us/ubbthreads/ubbthread...h/true/Re_main_halyard_sheave_delrin.htm

It has all the info you need. I would suggest you go with Delrine not SS and just buy it for $20.

DB

Bob,

The stock sheaves are shown on the Rig-Rite J/30 page. From this old post you can get critical dimensions for Clevis pin diameter that goes through the bushing.

I believe that these are the Harken Ball Bearing Sheaves that are now class legal.

Edit: I see David beat me to the punch with the old post!

ps - Welcome Bob! He's got J/30 Hey Jude in FL that we're trying to find the hull number on so he can be included in the class database.

Bill if those harken sheaves at that price fit at the bottom of the mast i am really interested. They are a touch wider at 1/2 in. than what the rigtite measures . but close.

Those harken sheaves appear to be too small re diameter. Rigtite one pictured is 1.75 in.

http://rigrite.com/Spars/SparParts/Sheaves.html#2 OD Sheaves
These are the choices that size that rigrite offers in that size:

1 3/4" Delrin Sheave - 1/2" wide, 5/16" ID: PP-S7D8-5:
Molded Delrin Sheave for use with rope. Sheave is 1 3/4" OD x 1/2" (.490") wide x 5/16" ID. With Rope Groove.

1 3/4" Aluminum Sheave - 1/2" wide, 3/8" ID: K-9951W-6:
Black Anodized aluminum Sheave is 1 3/4" OD x 1/2" wide x 3/8" ID. With wire/rope V-groove.

1 3/4" Aluminum Sheave w/ Integral Bronze Bushing - 1/2" wide, 1/4" ID: K-198-7AB4:
Anodized Aluminum Sheave with integral Oilite Bronze bushing. Sheave is 1 3/4" OD x 1/2" wide (w/ bushing) x 1/4" ID. With wire/rope V-groove.

1 3/4" Aluminum Sheave w/ Integral Bronze Bushing - 1/2" wide, 5/16" ID: K-198-7AB5: Anodized Aluminum Sheave with integral Oilite Bronze bushing. Sheave is 1 3/4" OD x 1/2" wide (w/ bushing) x 5/16" ID. With wire/rope V-groove.

1 3/4" Aluminum Sheave w/ Integral Bronze Bushing - 1/2" wide, 3/8" ID: K-198-7AB6: Anodized Aluminum Sheave with integral Oilite Bronze bushing. Sheave is 1 3/4" OD x 1/2" wide (w/ bushing) x 3/8" ID. With wire/rope V-groove.

Vic - now that I look at the Harken specs, it's only rated for 300#. I don't think that's high enough for the safe working load on the main halyard. So it isn't just the diameter that's different. The class measurer approved the use of ball bearing sheaves, but didn't pass judgment on any particular model number.

Thanks to all for your imput. I think I am going to go with custom made Stainless Ball Bearing Sheaves.

Capt Bob just be aware that mine were so stuck that it took me a good 30mn to drive them out and my mast was down... Also, you need to have you main halyard free (that is not buckled to your harness:-) to remove them...

For the sheaves, I arrive to the same conclusions. I just sent to Harken just in case I missed something and in case they have plan to increase their narrow sheave selection (http://www.harkenstore.com/uniface....409Z56LC7FV66&CATEGORY=409Z56LC5HN32 and http://www.harkenstore.com/uniface.urd/SCCYSPW1) to smaller ones...

I found this one (http://www.harkenstore.com/uniface.urd/scpdinw1.ShowProd?B4RPMEB9Y9BAO) but that would mean for me getting back to wire... :-(

I will forward any useful answer they can give me.
Good luck.
-- Georges

Garbled URL sorry: I meant
http://www.harkenstore.com/uniface.urd/scpdinw1.ShowProd?B4RPMEB9Y9BAOW
and http://www.harkenstore.com/uniface.urd/scpdinw1.ShowProd?B4RPMEB9Y9BIG0

Works for 1/4 line still... 1/4 crystaline can sustain an impressive load... food for thought.
-- Georges

Has anyone installed a main halyard sheave using the ball bearing option? If so what part number did you use?

I was just looking at the RigRite website and see that the J/30 sheaves on this page are the same as the J/24 sheaves on this page.

That means that the "standard" Sparcraft Delrin sheaves also offered on the J/24 page at Annapolis Performance Products should work on the J/30 main halyard.

The most accurate way is to take precise measurements of the old sheaves before removing them from the mast. This includes the sheave diameter, groove diameter (if applicable for wire rope), sheave width, and pin diameter. If you know the manufacturer of your boat, reach out to their customer service department. They might have spare parts catalogs or technical drawings that include the halyard sheave specifications. Stainless steel with ball bearings sounds like a great choice for durability and low friction. Make sure the chosen stainless steel grade is appropriate for marine use to withstand corrosion.

I replaced my main halyard sheaves to accommodate 3/8 line and got rid of the wire to rope splice a few seasons ago. So far so good. Dan #409