Inspection of the masthead sheave (pully-wheel-thing inside the top of the mast) shows that it is somewhat worn. Though it still seems to be mechanicaly sound I would like to replace it along with the spreaders and spreader bases that i now have parts for. Dwyer aluminum mast company has aluminun replacements (were I purchased two spreaders thanks to Commanderpete). Does anyone have any experience replacing the sheave, or any suggestions?
Funny enough, I looked into this recently. I have my mast down, and I removed the bolt that holds the upper stay tangs on. That bolt also holds the masthead sheave (but I wasn't thinking about that).
Anyway, a few weeks later I came back and found that the masthead sheave had disappeared. I figured it fell down the mast. After cursing for a while, I started thinking about a replacement/ upgrade. I didn't see any large sheaves at Dwyer (did you see any?) I found some at Harken
http://www.harkenstore.com/uniface.u...&409Z56LC5HLRU
look under "Big Boat sheaves" and "high load sheaves"
I don't even think they have the right size, and the prices were outrageous. I think our sheave is 6 1/2", I forget.
So, I decided to fish the old sheave out of the mast. Actually, it turned out the old one had fallen out of the mast and onto the ground and rolled away.
I pulled out the aluminum cheeks that are on each side of the sheave and I'm cleaning them up a bit. The sheave should roll more smoothly. Otherwise my phenolic sheave is in good shape and I'm going to re-use it.
How bad is yours?
There's a little bit on page 21 of the Manual about installing a bronze bearing. Still thinking about that.
Last edited by commanderpete; 03-31-2005 at 11:03 AM.
My sheave is somewhat worn but its also original which means that its 40 years old. As a kid my first job was in a rope mill (Wall Rope) and there were similar sheaves on some of the machinery which needed replacing every so often. Dwyer Aluninum Mast has them, click on hardware at the top of the web page;however, none of them are the right size though cheaper than Harken, Mike Goodwin says the original sheave in my mast should be alright.Mike and I went to a used boat parts auction last week, Mike said that there were some sheaves there the right size but we didn't wait for that lot to be auctioned off it would have been hours. I hate not replacing it but "she who must be obeyed" wants the boat back in the water so she can fish. The big Commander cockpit has plenty of room for a little fishing. Also replacing the damaged back stay tang with one that is thicker and a little longer so I can add an extra bolt as you know mine was completely bent over and had some hairline cracks.
Last edited by Robert Lemasters; 03-31-2005 at 01:59 PM.
The masthead sheave on 338 is 6.50"d x 1/2", grooved for wire. It has been frozen in the box. Someone fabricated a nice s.s. tang over the aft side of the dead sheave box for a halyard block.
If you wanted to restore the original external halyard over the sheave why not cut a circle of 1/2" delrin and find someone with a lathe to pare in a groove? Any ideas on this?
Any thoughts on a smaller offset sheave or two or three that would go internal? Someone is trying to persuade me to do this.
That's what I got--6 1/2" by 1/2", rope groove.
You should be able to get that sheave working ebb. You just jiggle those aluminum cheek plates out of the mast.
I scrubbed everything up and sanded off the corrosion on the cheeks where the sheave rides against them. I'll spray everything with McLube.
If you wanted to get two sheaves up there you would have to widen the slot in the mast.
If you wanted to use smaller diameter sheaves then the line might chafe on the bottom of the slot where the line enters.
Going internal would just complicate matters.
I did run across this guy who'll make you any size sheave you want
http://www.zephyrwerks.com/pricing.asp
Wow, the COSTS!
Don't even know if your guy goes up to 6 1/2" - 82 bucks for a 6". Another 1/2" and it'll skyrocket.
Extra for UV Delrin, Hell, HAS to be UVed up there.
With a router and appropriate bits, and given the large diameter of our sheave, it would be a piece of delrin to make one! Wouldn't be science, but close enough.
This someone one I mention cannot be questioned. He's a national treasure. I think the mast has enough in it with the electrics, and pointy fasteners. And there is a strong arguement for foaming at least the top of the mast as a safety measure. If you get flattened the mast could fill.
Cruisers, maybe everybody except racers, also like the ability to visually check the halyards and ease of replacement. Maybe my authoritive friend was just floating a comment to see what reaction he would get. Certain tricksters around here do it all the time!
Last edited by ebb; 04-01-2005 at 09:21 AM.
Don't try to goad me into taking on yet another project this year ebb.
All of my projects result in at least one crazy snafu.
That might amuse you guys, but its very painful for me.
like probably said already:
it's not the snafu itself.
it's how you go from the snafu to your next snafu!
Here are some recent photographs of my Commander #105 (Sparkey) renamed Njord, that was damaged in hurricain Isebel. I am now sailing, it was worth the effort, thanks to all of you with your kind advise and insights.
Last edited by Robert Lemasters; 11-14-2005 at 01:31 PM.
Nice mooring bitt. Did that come with the boat?
Nathan
Dasein, Triton 668
www.dasein668.com
No, I found the old bronze bit on good ol' Ebay, I have an arthritic condition in one hand, and the bit makes it easier to tie up. It is solid bronze, about 100 years old, so I'm told. I also found three Wilcox and Crittonden 5" portholes, I had two already, my stock portlights were dameged in Isebel and needed to be replaced, they open and let in air and are very water tight. Note the thicker stainless steel back stay chainplate, the old one was bent over and cracked.
Last edited by Robert Lemasters; 11-16-2005 at 12:11 PM.
Robert, I said this before when you posted another picture, but those round portals look fantastic! And your boat looks even better in the water too!
Have you redone the interior at all? Because, you know we'd all love to see some pictures of that too...
Mike
Totoro (Sea Sprite 23 #626)
Photo #126 shows what appears to be an upgraded stern chainplate. And, an indication of some past forward movement. High tension on the backstay or the Gene Roberts effect (hitting something while moving causing the mast to spring).
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