Rope vs Wire Braid halyards?

The SJ24 boat from the factory was normally supplied with conventional rope type sheaves. Not all boat owners actually installed wire rated sheaves at the top of the mast and it will cause damage if you run a wire rope halyard thru a rope style sheave. How to tell the difference?

• Rope type sheaves usually have a much larger diameter of the pulley, are made from plastic or metal and include a smooth half-round section profile that extends uniformly the full width of the sheave.
• Wire type sheaves are usually made from metal only, include a 45 degree flat shoulder and then a much smaller half-round section that doesn’t always have enough room for a normal sized rope. Some sheaves are dual rated for either wire or rope.

Historically the half rope, half wire rope method was a highly desired configuration for the halyards on a racing sailboat. It provided the best of both worlds: very low stretch and creep under tension between the rope clutch and the sail. And ease of handling and cleating by the crew. The technique to fabricate double braided rope to wire rope halyard is complex and is demonstrated here by Premium Ropes.

It has fallen out of favor as it difficult to maintain and requires wire type sheaves at the top of the mast. The newer double braid dyneema (HMPE) lines are just as good as wire rope and don't suffer from the difficult to service maintenance problems.

line splicing references

Line Splice Kit