Selden Jib Halyard Sheave Box Assembly with Plain Sheave

Hi Sean It depends on the mast design, if the measurements are close you should be fine, there is a very similar exit box which hooks into the mast at its bottom end and screws at the top, the new design screws both ends and is a pretty straight forward replacement. I have also seen designs of double sheaves in tandem fitted to a rack and these will require replacement sheaves to the rack or a new mast Regards David