replacing masthead sheaves

[gasdave]

I inspected the sheaves at my (unstepped) masthead today while removing the halyards for washing. One of them (genoa) was particularly rough looking around the edges but when I lifted the masthead out to investigate how it might be removed I discovered that the pin/bolt through the sheave has no obvious means of removal. It appears to be shear with the faces of the sheave on both sides.

How do I get it out for replacement? Does it need to be drilled or can it be knocked out? Is this normal? It's a 1987 Selden mast (I think!).

Also would an 8mm halyard be adequate for my Sadler 26 genoa? The current one is 10mm but looks a bit wide on the sheave.

 

[simonfraser]

if you can get the masthead out, you're lucky, take it to an engineering shop.
the pin could be corroded in and be a right pain to remove without the right tools / experience.

the halyard is unlikely to be any where near breaking strength.

just make sure it fits your clutches / sheaves / hands.

if the halyard is controlling a luff change it to dyneema for better control.

 

[Deleted member 36384]

gasdave the whole housing may have to be replaced if its a Sheave Box. the sheave boxes have a flange on the face which is pop riveted to the mast. The sheave sits inside the box. The sheave pin is pressed in flush and is an interference fit.

If by masthead you mean a Truck (Kemp I think) or Head Box (Selden) I do have a vague memory of knocking out a sheave pin from a silver / grey cast aluminium Truck. They were tapped out with a drift. Note, tapped out. Its the flush face of the pin that is triggering this memory and it would have been late 80s.

Good luck