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What part is this? Mystery masthead part

crznhwy1

Member II
I've taken my mast down to replace the rigging and other worn out items. I have a mystery part that I don't know how to identify. I have a '73 E27 with what I understand is a Sparcraft masthead. There are two bolts that run through the masthead that have a fiberglass or ceramic sleeve over them. These are not the pins that run through the sheaves. I need to replace those sleeves as they are pretty worn out. Does anyone have any idea what these sleeves are called so I can find replacements? Are they masthead rollers or sleeve bearings?

I am attaching photos of the mystery sleeves and where they are located on the masthead.

Thanks,

Mike
1973 Ericson 27 #359
 

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mherrcat

Contributing Partner
That's what they look like to me, too. But I really don't see any reason for them. From the pictures of the masthead it looks like there is a spinnaker halyard block attached to one and a static topping lift attached to the other.

Now that I look at it again, if that block were for the spinnaker halyard shouldn't it be outside the forestay? Maybe it is for a spinnaker pole topping lift?
 
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CSMcKillip

Moderator
Moderator
Well, My guess is that its a spacer so that the compresson of the nut and bolt do not bend the masthead in, and keep a tollerence.

My:egrin: 2 cents
 

crznhwy1

Member II
I don't know about the spinnaker halyard. When I got the boat there was nothing there but the block. I was wondering if these sleeves were for chafe protection for the wire/rope halyards and then the block and the topping lift were added later.

Mike
 

Randy Rutledge

Sustaining Member
Chris you are exactly correct they are compression tubes to prevent distortion of the masthead when the nut is tightened on the bolt.
 

CSMcKillip

Moderator
Moderator
Chris you are exactly correct they are compression tubes to prevent distortion of the masthead when the nut is tightened on the bolt.

Agree, but why not a aluminum sleeve, i think they also double for chafe because of the rigging is attached, i would hate to see that bolt after years of service without it installed.
 

crznhwy1

Member II
I was wondering the same thing. I've just replaced the aluminum compression tubes inside the mast. That's why I was thinking it might be for chafe protection for the halyards. They pass right under these bolts.

Mike
 

tadslc

Member III
I'd also agree with Chris, a compression spacer.

Also, I'd add I wouldn't use phenolic for this purpose.
 

tadslc

Member III
I'm no expert, I was just stating that I wouldn't use it.

With that being said, I wouldn't think phenolic tubing has much strength when used for this purpose (compression spacer). I've seen plenty of this type spacer built out of aluminum so that would be my first choice. Aluminum would also work fine for chafe protection.


Tad
 

crznhwy1

Member II
Thanks!

I appreciate everyone's input. Now I can get busy getting this mast back up and have everything ready for spring!

This forum is such a great resource. I'm learning a lot.

Mike
'73 Ericson 27 #359
 

mherrcat

Contributing Partner
I still fail to see the need for a "compression spacer" in that application. The forestay appears to be attached with a clevis pin (you can see the cotter pin) and my guess is the backstay as well. The only purpose for those bolts is to attach that block and the boom topping lift; why would you need to apply so much torque to the bolt to require some kind of spacer? My guess is there was nothing there to begin with and a previous owner added the bolts.

I found bolts replacing clevis pins on my boom vang blocks; who knows why...
 

crznhwy1

Member II
Mark, those are good points. I'll bet that's what happened. I've been searching for a break-down drawing of the old Sparcraft mastheads, or even pictures, but no luck.

With Loren's help I found the original material at McMaster-Carr and ordered some. The last ones lasted 20 or so years, that's good enough for me!

Mike
 
Don't break your masthead

Mark et al,

That compression sleeve was needed on a bolt here because the situation is not to enable so much torque, but to prevent any deflection of the masthead casting while tightening the nut. Cast aluminum is brittle, and very little effort is required to deflect it enough to break it. Bolts usually have a lock washer that needs snugging to stay in place, and the casting can fail before you realize it. I like a clevis pin here myself.

I learned this a bad way, while at the top of a 221' tower.
 

lindaloo

Member II
Make sure you use a new nyloc nut, and snug it up no more than the bare minimum. The sleeve could be there to match the ID of the block clevis, so it doesn't rattle around. A 2" length of hose slipped over the clevis/swivel might save the nice new paint you'll apply from getting scratched up.

Rob Lesnie
E34 Alia
Vancouver BC
 

crznhwy1

Member II
I've decided to go with clevis pins with a phenolic sleeve. I ordered some phenolic material from McMaster-Carr and got it in three days! I was impressed by their service. I'm just now ordering the clevis pins. I appreciate all of the advice.

Mike
 
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