J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment replacing wire halyard with rope, suggestions

3/8" is good. If you want low tech but good performance, try New England Ropes Sta-Set X. It has a parallel core with low stretch characteristics and costs much less than the high tech stuff. Splicing Sta Set X is a real pain, so you are better using a pro to splice on the shackle.