Replacing sheaves at base of the mast..

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Tom Boles

One of the items our surveyor noted on the survey was the deterioration (sp) of the sheaves hunter uses at the base of the Vision 32 mast. There are two groups of 3 and they look like bleached-out grey plastic of some sort. Has anyone replaced these? Any suggestions? I'll call Hunter if I need to, but I am thinking of an upgrade to reduce friction. (we're almost there-agreement to pre-final acceptance went out this evening...)
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Seco or Rig-rite

Tom: Try Seco or Rig-rite. If you check the archives you can find Seco's phone number. I think you will find Rig-rite at www.rigrite.com
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Have you taken delivery?

Tom: Did you take delivery yet? Where are you keeping the boat? Maybe we can get together sometime. We are up in the Delta. This is the place you should be during the summer (at least for a week or two). Great sailing and warm weather (you bay sailors don't know a lot about warm weather sailing in the summer, do you?)
 
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Tom Boles

We are really really close!

Hey Steve- I think we will have the final stuff taken care of end of this week, so the watch should change before the end of the month. We are in line to keep her at Coyote Point, just 5 miles from home (we are in Foster City). It's actually not too bad here in the South Bay, yes a lot warmer then the main bay for sure! We actually know the Delta a fair amount for Bay Sailors-We used to bring our Laguna 18 up to B&W, did it several years in a row. I've also sailed a Catalina 27 up to Potatoe, and one year to Lost Slough (and a Laser up the slough and under I-5!. Wy wife & I took a Catalina 34 up to Potatoe for a week before the kids were born, maybe 13 years ago. I've done the Ditch run twice, we've camped at Delta Bay & Sugar Barge and rented patio boats from Herman & Helen's. Now with our own boat, you can be sure we'll spend some time up your way!
 
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Rodger Beard

I've been there (and back actually <s>)

Tom, You'll recall that I was doing a lot of (re)rigging this spring on my V32 due to problems getting my mainsail up and down. Well, up until I got this problem solved I was going thru sheaves on the main halyard and sheet (no coincidence), especially at the base of the mast where the most line stress is, the same as on your V32. Anyway, I did call Hunter and they referred me to Layline in Raleigh, NC (800/542-5463). Layline had the sheaves in stock so I bought 10 at $4.75 each, in September of 2001. I received my shipment in about a week via standard UPS. Note that Layline is also on the web. I've attached a link. The part you need is CS48530501, acetel 50 x 14 (I copied this from my invoice.) Note that these new sheaves are made of stronger (denser) material and are a slightly different form-factor but have worked out well. More color: I tried later to replace all of my acetel sheaves with roller bearing versions. This to make all my sail halyards and sheets move smoother/easier. I called Layline twice and they said, both times, they would have to research for a few minutes and would call me back. They never did call back so I researched myself via the web and various other sources. After many, many hours I finally determined, to my satisfaction at least, that acetel is the only type sheave available in the size we need. Didn't want to change out the blocks so I gave up. (If anyone knows a source please let me know.) Hope this helps! Best, Rodger s/v Attitude Adjustment
 
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Tom Boles

Roger, your tracks make a path for me to walk!

I figured you had probably had done this already, so thanks BIG TIME for the info! I'll check in with layline & bring in the sheaves. (are there any other places on the boat that use the same size? why did you buy 10 rather than 6? Spares?)
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Rodger & Tom...

I also thought about replacing the sheaves with bearing type units. I was told by a couple of sources that this was not a good idea when you have a load like the mast halyards. They claim that they do not last very long because of the high load and the bearing are not moving so they get flat spots. Now whether this is a fact or not I really do not know.
 
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Mike Webster

Some additional thoughts. . .

Wow, a lot of good information. Steve is right on about Rig-rite. They have a wealth of information about Isomat spars, including the boom, vang, and mast. They also have the most complete listing of sheaves I’ve run across. For the high load areas such as the main halyard, you might want to replace them with an aluminum sheave with oil lite bushings. These would take the loading and run as friction free as possible for a plane bearing surface. However, and $35+ each, you probably wouldn’t want to use these sheaves everywhere. Lower load areas could probably use the stock replacement sheaves made from acetyl. I checked with Layline and the part number Rodger mentioned are in stock at $4.75 each. For the record, here are the sheave sizes for the boat: Boom, four in front and four in rear: 60mm x 14mm wide x 10mm hole size. Mast base, 50mm x 14mm wide x 10mm hole size. Mast head sheave, 85mm x 15mm wide x 22mm hole size. Vang sheaves, 85mm x 20mm wide x 22mm hole size. The boom is an Isomat NB-55. The vang is an NG2 Isovang. Garhauer has an exact replacement aluminum sheave with torlon ball bearings available that would fit the masthead. Its model number 36-MH and costs $44. I was told by Charleston Spars (who bought out Isomat and can be reached at 704-597-1502) that early versions of these sheaves failed under load, but had been redesigned and now worked well. Steve Dion’s comments about not using ball or roller bearing type blocks for high static load applications is somewhat correct. Practical Sailor is doing an article in the next issue (if you are a subscriber, you can see the next issue online before it comes out) on block testing and talks about that very issue. However, it’s a complicated issue without clear answers. You pay your money and take your chances. I’m with you guys in that I’m trying to reduce the friction in the line handling systems. If anyone finds the answer please pass it around. In the meantime, I still think the best answer , at least for raising the main, is to do it from the mast. It makes life a lot easier for those of us without an electric wench, and is a lot simpler and less expensive.
 
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Tom Boles

Mike, between you & Roger, I am way ahead of the .

...Game when it comes to this boat! I just got an email from the broker saying he has a verbal final aggrement from the owner! How is that for trust! Anyway, it looks like we will not be able to get the boat until the 27th, so I have some time to take care of a few things. Thanks for the extra info on the sheave sizes. Since I will have the mast down, I think I will R&R the masthead sheaves. You ID'd the size, Mike, but how many are there? 2, 3 or 4? Is there a crane for a spinny or not? I think I will reeve a chute halyard while I can. Any thoughts to diameter, type & length? Wow! The fun has just begun!
 
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Mike Webster

Masthead sheaves

Hi Tom, As you've figured out by now, I'm a little wordy. It comes from the Engineer in me, I guess. Since you once asked, I'm a mechanical engineer in the automotive electronics field, mostly doing Project Management. Serendipity has lead me to the Atlanta area, wonderful weather, beautiful surroundings, but a lack of big water to sail in. The masthead has two main halyard sheaves, but only one is used. I think it'd be a waste of money to change them both out. For the questions concerning the spinnaker, it would be nice to hear from someone out there that has a factory installed spinnaker package. I had Hunter send me two pages eons ago showing the factory spinnaker setup. Most of it is definitely add on. However, you should (I think) have blocks and exits already in the mast. The standard package should have an exit block for the spinnaker halyard 18" above the forestay. It should have an exit block for the topping lift 6" under the forestay. When I added my spinnaker, I checked with Isomat about using an oversized spinnaker, and while they would not endorse it, they agreed that the mast was overbuilt and would hold it. With that in mind, I added a bail at 38' above the deck (about 5' above the forstay attachment) and put an external halyard thru a block at that point. I use the spinnaker halyard as the topping lift. The drawings show the standard chute halyard & topping lifts as 3/8", but I've found 7/16 to be easier on the hands. While its down, I would try to run the chute and topping lift halyards. You might try something like an electricians snake, but it would have to be pretty long. Standard line lengths for both chute and topping lift are shown as 90', but that seems long, especially if you end them at the mast as Hunter shows and don't bring them back to the cockpit. I would probably recommend doing that, but lets hear what others have done. If you want, I have Hunter drawings of their setup and could fax them to you. Let me know.
 
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Tom Boles

Boy, are there things WE could talk about!

Mike- Thanks for the details-and no apologies necessary! I've worked on a couple of electronic projects for tier 2 folks myself! How are the new sails?
 
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