Can it really be this straightforward?

[smokey73]

I need to replace the topping lift and also replace the sheave on the top of my mast. When I sent somebody up to replace the anchor light, he took a picture of the sheave. Looks like maybe the same bolt goes all the way through the masthead and holds the sheave for both the topping lift and for the main halyard? Has anyone every done this. It looks like it may be doable with the mast up but don't want to pull a bolt and drop the main halyard sheave at the same time. Any perspectives from looking at the picture.

 

[dlochner]

So, when the bolt is pulled, what happens to the halyard sheave and more importantly what happens to the halyard? Also, having 200+ lbs hanging on the sheave may make getting the bolt out difficult and even more difficult to reinsert it.

If you can find a marina with a man lift, so the person doing the job is not hanging on the halyard, then it probably can be done with the mast up.

 

[smokey73]

All good points @dlochner - If you look closely at the picture it appears (I say appears) that the masthead immediately below the sheave for the topping lift is solid and the topping lift line comes up through a hole. The boom is now supported by a rigid vang so there is no pressure on that sheave. However, as you say, if the same bolt goes through both the main halyard and the topping lift sheave then it would be nearly impossible to remove the bolt with a person hanging from the main halyard as shown in the picture.

I don't have to have the topping lift with the new rigid vang and my mast height is 64 1/2 feet above the water so finding a man-lift high enough for that might be a challenge. I was just going to use the topping lift as a spare halyard.

Any additional perspectives are appreciated.

 

[JamesG161]

Only a guess...

You need a different type line for your topping lift.
Smaller size and non-fraying type.

Jim...

PS: I need to replace mine soon.

 

[JoeWhite]

It appears that this sheeve was added by a PO. The line has fallen off the sheeve and can not be used. If I was going to replace it, I would replace the main halyard with a 1/8" line to remove the load on the main halyard sheeve. Then remove the nut from the bolt and carefully push the bolt out with an other bolt of the same size and type. Then replace the sheeve when the bolt reaches on this side. This will reverse the orientation of the bolt making it easier to replace the sheeve later. Then install the nut. I suspect it uses nylon locking nut as overtighening would prevent the sheeve from turning.

 

[LloydB]

i'd like to hear the reply of the person that took that picture. when you ask them that question

 

[kloudie1]

Ya might want to replace that sheave with a better material so it doesn't have to be done again.
Sheaves for masthead, staysails, booms, halyards — Zephyrwerks, The Sheave Factory

 

[Will Gilmore]

Did your guy take a good close look at the main halyard sheeve? Considering the wear on the topping lift sheeve, especially if it was a later addition, it may be time to replace both sheeves.

It should be easy enough to make the bosun's chair fast at the top of the mast so you can transfer the load off the halyard while you work.

-Will

 

[jssailem]

Hi Smokie.
Yes the topping sheave has lost it's shoulder. This is not an usual event for plastic sheaves.

Replacement is by removal of the bolt. It would be sweet if you could just pull the bolt. I do not think that will work. I believe you are correct about the bolt going through both the topping lift and the main halyard sheaves. I wonder what is the condition of the Main halyard sheave.

With the main halyard not usable as a lift you may need to rely on the jib halyard. Perhaps use a spinnaker halyard as back up . This would free the main halyard. The trick is to secure the main halyard sheave before you pull the bolt out so it does not fall down inside the mast. Taking the strain off the main halyard is a start. I have seen a rigger stick a piece of wood in under the sheave to keep it in place while you slide the bolt out. I would chase the bolt with a second to fill the sheave hole and keep the sheave in alignment.

Once secure you can go about removing the old topping lift sheave and replacing it.

Winter is coming to your part of the country. If it has been a few years since the mast was inspected, you might consider this a good time for such a project. Delrin is a good long lasting material for sheaves. I sourced my sheaves at Zephyrwerks, The Sheave Factory

 

[Rich Stidger]

Hi Smokie.
Winter is coming to your part of the country. If it has been a few years since the mast was inspected, you might consider this a good time for such a project. Delrin is a good long lasting material for sheaves. I sourced my sheaves at Zephyrwerks, The Sheave Factory

I think this is your best option Dan. I am certain that the topping lift and main halyard sheave run on the same bolt. Looking at my pictures I think it would be very difficult to change without dropping the mast. I will try to post all of my pictures for your reference.

 

[Rich Stidger]

@smokey73 -

Dan- Here is a link to all of my masthead pix on my Google drive. Anyone with this link can view.

Masthead - Google Drive

drive.google.com

Let me know if this link doesn't work. I don't use Google drive very much and I often have operator error problems.

 

[Jacktar]

Replace topping lift sheave with a pulley and proper sized line on a swivel.

 

[jssailem]

Looking at the image by expanding it and focusing on the Main halyard, It appears the main halyard sheave is also white. That leads me to believe the sheave is made out of the same material as the Topping lift sheave.

Sure it has been more protected from UV damage than the outside sheave. My guess is it will be needing replacement before to much longer.

Most of us wait till they break before we change them. They degrade and may make the halyards a little harder to pull before they stop.

 

[smokey73]

Just in answer to a few of your questions or comments:
1. No, this is not a PO modification. The Z-Spar catalogue for my mast shows this as an original part with the topping lift installed as it is shown.
2. The line that is there was a 3/8 double braid line/wire topping lift. It should have been replaced a long time ago and finally frayed and exposed the core. It is the core you are seeing pulled down beside the current worn white sheave.
3. I don't have to have the topping lift as I now have a Garhauer Rigid Vang. I just was thinking of keeping the existing topping lift as a spare halyard.
4. All good points regarding the condition of the main halyard sheave. The main halyard is brand new and right now the main raises and drops easily although I will explore replacing the sheave as preventative maintenance in the near future.

Thanks all for your perspectives and @Rich Stidger I'll look through your pics.

 

[smokey73]

@smokey73 -

Let me know if this link doesn't work. I don't use Google drive very much and I often have operator error problems.

Worked fine, Thanks Rich

 

[Benny17441]

Hire a rigger for a couple hours, he will have the harness, tools and experience to perform the job safely and quickly without the expense of dropping the mast. That sheave looks worn and the other one should not be far behind.

 

[PaulK]

Benny's idea about hiring a rigger would be cheaper than having the mast pulled. This is the sort of DIY project that could get you killed quite easily. A tougher material for the sheave would be desirable if you want to use it as a possible halyard. Topping lift loads are minimal compared to the pull of a halyard.