[Public-List] Mast Sheave

[Glennb]

Hi Randy,

The bolt and tube on Dolce were stainless steel and aluminum respectively.  Seven years ago they came apart with difficulty when I replaced the sheeve.  This past year they did not, and were solidly frozen together due to aluminum corrosion. Same with the  nut on the bolt holding the spreader tangs.  My crewman had to torque the spreader bolt with enough force to sheer the nut off at the bolt.  i had planned anyway to have a rigging shop cut off the masthead and replace with a new five sheeve welded aluminum ocean service masthead, so didnt care about salvaging the old masthead bolt and sheeve.  We also reinforced the spreader support with external plates fitted to the mast and put in a new compression bolt to distribute the spreader load.  

Not sure if this info helps your situation.  If the bolt and reinforcing tube are frozen in place, its awfully hard to impossible to free them up.  I guess work on them with lots of heat cycles and WD40 or other penetrating oil  enuf to extract the bolt.  If not, i suppose you would need to takeoff the mast head and cut the sheeve and bolt out from inside the mast, then replace with new parts and reinstall the masthead.

I did save my old cast aluminum mast head if you need it.   I cleaned off the surface corrosion at the tangs and found them to be in excellent condition.  A local foundry owner told me cast aluminum fittings like the  mast head get stronger with age.  So I suppose the original mast head could be serviceable for many years into the future.

Glenn
Dolce 318

Sent from my iPad

On Jul 10, 2013, at 10:33 PM, "randall weatherspoon " <rlwspoon at earthlink.net> wrote:

> I have been trying to change the sheave for the main halyard - I don't know
> if it is froze up hard and don't know how much force I can put on it. Also
> it looks like there is a tube that keeps the mast from being crushed - is
> that fixed or will it come out if I get the sheave bolt out? Any information
> would be helpful---
> 
> Thanks,
> 
> Randy     Marisel #385
> 
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