I need to replace some 2-inch sheaves in my boom and will be doing it myself.

Current sheaves are Aluminium with bronze bushings, fitted around 10mm stainless pins. I include a photo of one of the sheaves.

I would prefer to replace these with synthetic sheaves - and have read that you can use Nylatron, or Delrin, or Acetal, or Acetal with "Oilite" bushings.

Since I may be running spectra/dyneema through these, perhaps Delrin or Acetal will be too soft. I understand Nylatron is a very robust plastic that can handle even steel wire halyards.

So my question - has anybody replaced sheaves in the last few years, and what did you choose for replacements? Or any other recommendations?

Ramona said..

Easy to make if you have the stock.

... and a Lathe. No Ramona I'm planning to buy off the shelf. Will Delrin/acetal go brittle exposed to UV over say, 5+ years? I'm not sure.


Thanks Lazzarae, checked out that shop but none of my sizes available there (OD 50mm and 60mm & width 12mm or half inch)

Karsten said..

Ramona said..

Easy to make if you have the stock.

... and a Lathe. No Ramona I'm planning to buy off the shelf. Will Delrin/acetal go brittle exposed to UV over say, 5+ years? I'm not sure.


Thanks Lazzarae, checked out that shop but none of my sizes available there (OD 50mm and 60mm & width 12mm or half inch)

The Delrin sheaves on my yacht are 30 years old. If they have sharp edges they do chip but are easy to replace. I do have a lathe and Delrin is a pleasure to work with. I have made sheaves turned up in an electric drill though.

I would check out Bias or Whitworths. Delrin is not always white. There are usually some on eBay but seem to be absent at the moment.