H35 topping lift sheave

[richk]

The sheave for the topping lift on my Hunter 35 Legend has a nick in it which causes the line to jump out of the groove and jamb. (The adjustable topping lift is something that was added to the boat. It's not the original configuration.)

I believe there's only one shaft for both this sheave and the main halyard sheave. Since this halyard is used to haul someone up to the top of the mast, is it possible to replace only the topping lift sheave without unstepping the mast?

Rich

 

[Don12364]

Yes

I had same problem but it turned out to be a much enlarged central hole in the sheave.
It can be done but the risk of dropping bits is high!
I went up in my bosun's chair as high as possible. I was carrying a spare short length of line and a 1/4" shackle. When aloft I shackled the chair to a small hole in the masthead crane which extends aft. I doubled this using the line as a safety rope. Then I called for the halyard to be slackened off and I hung on the shackle and safety line.
If your mast is Z spars it is a single 1/4" dia bolt about 4" long holding both sheaves. The main halyard sheave is between the cheeks of the casting whilst the topping lift sheave is on a stainless bracket on the port side of the mast. I cannot recall whether the sheaves run directly on the bolt or whether they are on bushes - I suspect the latter (1/2" diameter?)
In my case the securing nut which was supposed to prevent this bolt working out was loose and almost on the end of the thread - not a thing one checks regularly!
Anyway it is possible to pull both main halyard and topping lift off their sheaves and put them over the masthead out of the way.
Now it will be possible to extract the bolt and replace the sheave. I suggest putting a string tightly round each sheave first so they cannot drop into the mast.
Then use a locknut on the bolt.

 

[John Nantz]

Return to original configuration?

If the mast is an Isomat mast, your thinking is correct that there are two sheaves on one axle. What Donalex suggested is, essentially, the only way to work on it without unstepping the mast. Somehow you'd have to have a way to support yourself to take the load off the main halyard.

It'd be a good idea to make sure that however you supported yourself using an alternative method that it would be possible to go up and down using that method in the event that 'stuff' happens, f.e., the axle accidentally falls overboard.

What about the idea of reverting back to the original configuration? A cable attached to the masthead that runs down to the aft end of the boom with a small block, say, about a foot above the boom. Run a line from the end of the boom, up to the block and back down to the end of the boom, then through a sheave to the goose-neck, down to the foot of the mast, then aft to the cockpit?

 

[tkanzler]

Here's a pic of the ZSpars mast head

You can see the topping lift sheave outboard of the head casting, and the main halyard sheave buried inside on a common axle with the TL sheave. Mines chewed up pretty badly (nylon, and exposed to UV), which I discovered when I went up there a month ago, but I'll take the mast down this winter to replace it, along with some other work that needs doing.

Sorry for the poor quality, but I took this from the ground with a digital camera at high resolution, and zoomed in and cropped it.

 

[cbsailor]

Yes You Can!

Yes. I had a similar problem with my H33.5 (ZSpar Isomat mast). The topping lift sheave had broken and the line was jammed. Using the main halyard and my Mast Mate ladder I climbed aloft to see what the problem was. I was able to see the broken sheave and clear the jam. I returned to the deck and started taking the Mast Mate down when a piece of the main halyard sheave broke off and landed at my feet. Now I had two broken sheaves and the high probability of jamming the main halyard and topping lift. It was time for some research. I located a drawing (IPB) of the mast head and determined that both sheaves were indeed on the same axle. The drawing also provided me with part numbers. I contacted Hunter for parts and was referred to Rig-Rite. I checked out their website and then called and ordered new sheaves. By the time the sheaves arrived I had devised an installation plan with the help of an inquiry to owners here on this site.

On the back of my mast just below the mast head are two rectangular holes that were key to the plan. I gingerly hoisted the Mast Mate using the main halyard again. I then climbed to the top and ran a short length of line with chafe protection through the two rectangular holes and tied off the Mast Mate. Since this was a “solo” adventure, I climbed back down, released the main halyard and took the load off the topping lift line. I then tested the Mast Mate to make sure the tie-off would support my weight. It held so I climbed up again and began to remove the mast head cap. It is held in place by two “J” bolts and nuts. The nuts are located in the cap recesses and it will require a ratchet, extension and socket to remove the them (the nuts are metric, 19mm). Once the two nuts are removed, the cap can be lifted and turned ninety degrees to access the sheaves. I then pulled slack up and out of the mast for both lines (halyard & topping) and tied them off with another short piece of line. Now I could clearly see how the sheaves and axle simply drop into the mast head casting. I lifted the axle and sheaves out of the mast head, removed the broken sheaves from the axle, installed the new sheaves and set the axle/sheaves back into the mast head slot. It wasn’t easy and I was afraid of dropping parts, but I just kept telling myself “slow and sure” with each step. Releasing the halyard/topping lines and making sure they seated onto the sheaves properly was followed by reinstalling the cap and securing the nuts. Then it was another trip down to take up slack on the halyard/mast mate. Another quick weight test and it was back to the top to remove the line holding the ladder to the mast. A final descent, remove the ladder and it time for a beer. Not bad for a 62 year old if I do say so myself!

BTW, I did use the Mast Mate safety belt and the jib halyard as a safety line. I opted to install aluminum sheaves versus the “plastic” ones. Good Luck to you on your repair.


Link to ZSpar IPB http://www.zsparsuk.com/z501.htm
Link to Rig-Rite www.rigrite.com
Link to Mast Mate www.mastmate.com

 

[cbsailor]

Pics of bad sheaves

Here's a photo of the bad sheaves that I removed. The "Walls" of the sheaves just break away due to UV and element exposure over time.

 

[John Nantz]

Do work at haulout time?

cb - I'm impressed! Didn't realize it was so much work and so many places where things could go wrong.

If the J-bolts were stainless steel, how did they fair in the aluminum masthead? I'm surprised they weren't corroded with aluminum oxide and that you could actually get them apart.

Working aloft without loosing a single piece - wow! After reading this I'd recommend doing the work during haulout time in the yard with asphalt underneath. With so many parts and pieces and being aloft in a difficult working situation there is a likehood that something falls down, and ker-plunk/splash. Now it's time for the diver, or worse, trying to find a replacement part somewhere. Good luck. Now is this job getting difficult or what? (at least that's the way my jobs seem to go)

I've never replaced my sheaves but it appears the axle might (fingers crossed) just drop in a couple slots???

 

[cbsailor]

Take a look at the IPB

Take a look at the IPB link. I never took the "J" bolts out of the mast. In fact, the "J" bolts hold the mast head casting into the mast with two nuts and two additional nuts hold the mast head cap onto the mast head casting. A total of four nuts all on the same two "J" bolts. Yes there was a small amount of corrision under the second set of nuts holding the casting into the mast. I did not remove these. That's a job to be done with the mast down. I was working may way back north from FL this spring when I had to do the repairs. Unfortunately I won't be headed south this year as I promised the admiral I would remodel the master bath/bedroom and it won't be completed in time to go.

 

[Don12364]

CBSailor

Ever since new the topping lift on my H376 (1996) has frayed at the masthead. This usually takes about 3 months and if it frayed right through there would be a problem. Originally I started cutting off a yard and re-making the connection to the covered wire which comes down to the boom end.
I went to the masthead several times and eased out the hole in the masthead and filed it smooth - but all to no avail.
Eventually I spliced six feet of 1/8" stainless steel halyard wire onto the end of the rope and have an eye which connects to the covered wire. This was several years ago but, even now, the wire has become 'prickly'.

My question is; when you lifted the masthead fitting, did you see anything which could be causing all this chafe? e.g. the in mast conduit etc.

BTW my mast section is Z601 but I see all the details are common.

 

[John Nantz]

Fractional rig => can't use jib halyard

Dana - the H35 is a 7/8ths fractional rig so the jib halyard won't get you up there far enough.

And speaking of masts, my 35 has an Isomat mast and the masthead is configured differently from the ZSpar diagram.

It's nice the ZSpar people have access to on-line diagrams of their mast. I've got a hard-copy of an Isomat catalog which shows details and part numbers but can't display it without scanning it first and there's no time right now.

 

[richk]

thanks to all and another question

I appreciate everyone's response on this topic. Since I currently do not have the time to go aloft or the money to pay someone, please let me know what you think of this idea. The topping lift sheave has a nick in it. A larger diameter line would pass over the sheave without risking catching the nick and jumping out of the track.

Thanks again
Rich

 

[cbsailor]

Where is line being damaged?

Donalex

Ouch! Chaffing the line is one thing, but damage to wire rope is extreme. No I didn’t see anything that I would suspect. My topping lift is all rope and fortunately I have not experienced any problems other than the broken sheave.

IIWM, I would remove the cap and check for screws, bolts etc used to mount something to the cap or side of the mast like antennas, wind monitors and the like. I did find my wind monitor and windex mounted with SS sheet metal screws. They are now through bolted with lock nuts.

Another possibility is if the line is not entering the sheave at the proper angle. It could be wrapped on the main halyard or even behind the jib halyard further below. I’d be interested to know the answer when you find the problem. LOL with it.

 

[cbsailor]

Not recommended.

Rich,
I would not recommend using a larger line. The "plastic" sheaves usually break on the "wall" areas. Larger line will only add to the pressure on the walls and possibly break more of the wall out. If the wall is broken you can bet the main halyard sheave will be soon to follow.

 

[John Nantz]

Put block on end of existing topping lift line?

The topping lift line doesn't take a lot of force so if it's not too far gone and you want someting to get you by, what about puting a block on the bottom of the line about, say, a foot above the end of the boom.

Then run another line starting at the end of the boom, up to and through the block, back down to the end of the boom, through a sheave at the end of the boom (there should be four of them) and forward to the gooseneck, down to the base of the mast, then aft to a winch or sheet stopper. This is how the original setup went and it should work fine or at least get you by.

Just a thought of a possible work-around.