replacing sheaves on the centerboard lifting mechanism

[Gerry Connolly]

I'm trying to replace the old shaeffer sheaves on the centerboard lifting mechanism with Harken 311 2" sheaves. The problem is the bolt is 1/4" with a 3/8" expander sheave to accommodate the old shaeffer rope sheave. The harken 311 needs a1/4 to 5/16 spacer sheave.
If anyone know what I'm trying to describe and have any ideas, I'd appreciate the help.

[dave]

If memory serves me well, I just drilled the holes out to the size pin that was needed for the Harken sheaves and then installed all with the correct clevis pin. While I was at it I drilled another hole right under the mounting plate and added another pin to act as a dead end for the line.

Have you read the 2 page thread about daggerboard blocks replacement at the bottom of the page?

[Mark Rode]

I just completed the upgrade to Harken 311 sheaves. I cut a spacer out of 2" delin round stock to shim for the narrower sheaves. I left the larger holes in the main bracket as is. The smaller diameter pin for the harken sheaves will work fine, all the load is in one direction. I'll make bushings next year. I used harken 307 and 311 sheaves on the tang. I drilled out the cheek from the old scheafer fiddle block to accept the larger bolt (lower sheave only) and then shimmed out the whole block (1/2" x 3/4"x 5" aluminum bar stock) to line up with the lifting bracket. I drilled a hole to dead end the line just outboard of the upper sheave. Everything is now in a straight line and the reduction in friction is amazing. I then had to replace my sheet stopper to accept the smaller diameter lifting line (1/4" sta-set). A little more costly than anticipated but well worth it. My crew likes it.

[Gerry Connolly]

Thanks. I got the sheaves installed, the old sheaffer blocks got mangled when I drilled them out to 5/16" but the cheeks were still good, shimmed to keep the 1/4" rope in place. Makes a big difference. Did you just replace the jaw on the spin-lock line stopper or replace it with something different? I should also replace the turning block on the deck. (next year) Gerry C. Tweak'n + Tug'n

[Mark Rode]

I had Lewmar stoppers and replaced with a Spinlock to handle the 1/4" line. Works great. I haven't changed my deck block yet either. I keep saying I'll do it next week but more likely next year.