Masthead Cap

Posted by jerry_magic1 (jerry_magic1@…>)

Somebody posted comments some time ago, either on this board or on
the old Freedom board, that I can not find now. Some of the
discussion involved replacement of the main halyard sheave at the
top of the mast with one of larger diameter. Purpose was to further
reduce halyard friction when raising and dousing the main sail.

I’d like to know if that was done on a carbon fiber mast. If so,
how much trouble and what was involved in removing the masthead cap
to get at the sheave? Also, what diameter was the replacement
sheave and which Freedom model boat was it?

I’ll be pulling the mast next month on my F36 to completely rewire
it and I’m thinking of installing tricolor running lights. Removing
the masthead cap will make the work easier if it is not too
difficult to get the cap off.

Posted by Bay Skipper (bayskipper@…>)
Raising the main on my 1987 F-30 had become an almost impossible chore. About 3/4 the way up, the halyard was very tight and it would actually start squeeking when I would wench the rest of the way up. It put a tremendous force on the halyard. I also noticed that the main would not drop to the boom like it used to. I’d have to get on deck and tug the main down manually. It was no fun to raise and lower the main, and at times I thought the halyard might actually snap.

I was looking into a track system to make it easier to raise and lower the main and got quotes on having one installed.

I moved the boat last year by truck and was checking the mast the wiring and masthead before restepping. I noticed that the sheave at the top of the mast was frozen, It would not budge. I took the bolt out and tried to remove it and found it also to be welded by corrosion to the masthead. I could not remove it with the tools I had onhand, so I hired a rigger who was onsite to help me. It took him a half an hour to break the sheave loose from the masthead. It was frozen in there very tightly.

Once removed, he had to soak the sheave in a solution for another half an hour before he could break it open to clean it out. He washed all the bearings (which were nylon), lubricated it and reinstalled it. At this point it spun freely on the masthead, and afterwards the main went up easily as it used to. Obviously, with the sheave frozen, a track system would not have helped the problem. The sheave must, of course, spin freely.

As I recall there was not much clearance at the masthead to increase the diameter of the sheave. I would have felt more comfortable about the procedure had we replaced the sheave with a new one, but at the time that option was not available to me.

On my masthead I would like to note that there are dissimilar metals that come in contact with one another. The sheave was one metal, the mathead was aluminum, and the bolt was stainless, so doubtless in time corrosion is inevitable in a salt water environment.

This is a difficult part to get to with the mast up. I can not imagine trying to remove the sheave on my masthead (frozen the way it was) from a bosun’s chair. It required soaking the area with liquid wrench and a prybar to finally break it loose.

Removing the masthead cap was a breeze.

jerry_magic1 <jerry_magic1@…> wrote:
Somebody posted comments some time ago, either on this board or on the old Freedom board, that I can not find now. Some of the discussion involved replacement of the main halyard sheave at the top of the mast with one of larger diameter. Purpose was to further reduce halyard friction when raising and dousing the main sail.I’d like to know if that was done on a carbon fiber mast. If so, how much trouble and what was involved in removing the masthead cap to get at the sheave? Also, what diameter was the replacement sheave and which Freedom model boat was it?I’ll be pulling the mast next month on my F36 to completely rewire it and I’m thinking of installing tricolor running lights. Removing the masthead cap will make the work easier if it is not too difficult to get the cap off.

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Posted by George E. Herchenroether (g.herk@…>)

Our F45cc masthead was enlarged by Paul Dennis at his shop in Warren. We also switched to T900 halyard and a STRONG track. The result is pure silk both up and down. Paul can custom fit your masthead to the larger sheave.

Posted by tlira5752 (tlira5752@…>)

I replaced the sheaves on my 38 this past summer. I used Harken
sheaves. I believe Mark Edwards indicated that there may have been
more than one type of masthead cap used. I was able to redrill and
reposition the location of the sheaves.

The sheaves really did the job. I was ready to do the track thing.
What a simple and cheap solution to a chronic and potentially
dangerous problem. I am not even considering cars and tracks now.

I also ran PVC pipe in the mast a conduit for wiring. That seems to
have worked. I found rotten and deteriated pipe insulation in the
mast when I pulled the stick. It probably worked great for a few
years.