My solution...(s)
The sheave will easily handle up to 1/4 inch diam. You cannot put wider sheaves in the slot because of the mastead fitting restrictions. That's why the high tech line was on your boat in the first place. The rigger should have know that Cat 27's have limited clearance for larger sheaves.Three solutions without replacing sheaves: 1)Replace with a 3/8x1/8 rope to wire halyard. You can purchase these from Defender.com for about $65.00. West Marine charges $119 for the same halyard.2)Replace with higher rated smaller diam line like 1/4 sta-set X.3) build a "tapered" halyard. High tech core with polyester cover. I tried second method, halyard works fine but the line is too small to handle comfortably. The are cleating problems also.I settled on building a tapered halyard. 3/16 technora (tech 12) single braid, and covered the handling part with 5/16 Samson LS. Total cost, including thimble was about $85.00 The eyesplice on the single braid is very simple, and the taper part (burying the cover into the core) was not difficult either. There are types of cordage made that are designed especially for this application... Samson "warpspeed" for example. The core is UV treated, you simply strip off the cover where you won't need it. It is expensive though.My next halyard, however will be a wire to rope, as I am going to install roller furling. Check the Annapolis Performance Sailing website (link below) for some examples and price estimates.